174 results on '"Stefanović, Andrea"'
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2. Influence of ultrasound probe treatment time and protease type on functional and physicochemical characteristics of egg white protein hydrolysates
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Stefanović, Andrea B., Jovanović, Jelena R., Balanč, Bojana D., Šekuljica, Nataša Ž., Tanasković, Sonja M. Jakovetić, Dojčinović, Marina B., and Knežević-Jugović, Zorica D.
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- 2018
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3. Controlled enzymatic hydrolysis for improved exploitation of the antioxidant potential of wheat gluten
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Elmalimadi, Mohamed B., Jovanović, Jelena R., Stefanović, Andrea B., Tanasković, Sonja Jakovetić, Djurović, Sanja B., Bugarski, Branko M., and Knežević-Jugović, Zorica D.
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- 2017
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4. Production of enzymes by a newly isolated Bacillus sp. TMF-1 in solid state fermentation on agricultural by-products: The evaluation of substrate pretreatment methods
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Salim, Abdalla Ali, Grbavčić, Sanja, Šekuljica, Nataša, Stefanović, Andrea, Jakovetić Tanasković, Sonja, Luković, Nevena, and Knežević-Jugović, Zorica
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- 2017
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5. ENHANCEMENT OF THE BIOACTIVE AND NUTRITIONAL PROPERTIES OF SOY PROTEIN CONCENTRATE THROUGH THE USE OF ENZYME TECHNOLOGY
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Mijalković, Jelena, Stefanović, Andrea, Pavlović, Neda, Šekuljica, Nataša, Jakovetić Tanasković, Sonja, Gazikalović, Ivana, Knežević-Jugović, Zorica, Mijalković, Jelena, Stefanović, Andrea, Pavlović, Neda, Šekuljica, Nataša, Jakovetić Tanasković, Sonja, Gazikalović, Ivana, and Knežević-Jugović, Zorica
- Abstract
Soybean, a protein-rich leguminous oilseed, is often unacceptable due to its taste, appearance, and smell. Enzymatic technologies offer an alternative to conventional chemical procedures for protein modification, allowing for accurate oversight and adjustment of reaction flow to desired nutritional and bioactive properties due to the high sensitivity of protease under mild reaction conditions. Herein, the feasibility of implementing a one- or two-step biotechnological process, triggered by commercial endo- and exo-peptidases, to enhance the nutritional and bioactive characteristics of soy protein concentrates (SPC), was investigated. Two nutritionally valuable fractions, the hydrolysate (liquid stream-fraction) and the ocara (solid stream-fraction), have been separated. The hydrolysates were characterized by examining the crude protein content, protein recovery, and free amino group content. The antioxidant activity was quantified by measuring superoxide radical inhibition, and metal-ion chelation. Commercial peptidases led to different reaction kinetics and protein recovery, resulting in different peptide profiles determined by dead-end ultrafiltration (3, 10, and 30 kDa) and subsequent gel-filtration chromatography using the Toyopearl HW40F resin. Enzymatic hydrolysis seemed to enhance the hydrolyzate's protein content while decreasing the ocara's protein content. The percentage of soluble protein recovered from SPC ranged between 68 and 82%, revealing that Flavourzyme was most suitable to solubilize SPC. The highest yield of hydrolyzed peptide bonds, correlated with higher antioxidant activity, was shown by Alcalase- Flavourzyme (~20%) as well as Neutrase-Flavourzyme (~21.5%), with a tendency to favor Neutrase due to more sensory-acceptable product. Each produced hydrolysate's amino acid content, sulfhydryl groups, and surface hydrophobicity have been examined, and substantial correlations with antioxidant activity have been found. Because the quantity of phytic
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- 2023
6. Impact of Different Enzymatic Processes on Antioxidant, Nutritional and Functional Properties of Soy Protein Hydrolysates Incorporated into Novel Cookies
- Author
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Knežević-Jugović, Zorica, Culetu, Alina, Mijalković, Jelena, Duta, Denisa, Stefanović, Andrea, Šekuljica, Nataša, Đorđević, Verica, Antov, Mirjana, Knežević-Jugović, Zorica, Culetu, Alina, Mijalković, Jelena, Duta, Denisa, Stefanović, Andrea, Šekuljica, Nataša, Đorđević, Verica, and Antov, Mirjana
- Abstract
Soy protein concentrate (SPC) was hydrolyzed using several commercial food-grade proteases (Alcalase, Neutrase, papain, Everlase, Umamizyme, Flavourzyme) and their combination to obtain promising ingredients in the manufacture of functional bakery products. In all cases, the hydrolysis caused nutritional, sensory, and rheological changes in SPC, as well as protein structural changes like increased surface hydrophobicity and content of exposed SH groups with the magnitude of these changes depending on enzyme specificity. The hydrolysis with the combination of Neutrase and Flavourzyme (NeuFlav) increased essential amino acid content by 9.8% and that of Lys by 32.6% compared to SPC. This hydrolysate showed also significant antioxidant activities including ABTS and superoxide anion scavenging activity and metal-chelating ability. The addition of all hydrolysates in wheat flour decreased water adsorption and increased development time to some extent due to gluten network weakening, but also decreased the rate of starch retrogradation, contributing to the increase of the shelf-life of bakery products. The NeuFlav tasted less bitter than other hydrolysates, while E-nose provided a discrimination index of 93 between control and hydrolysates. It appeared that the addition of the NeuFlav hydrolysate in a cookie formulation improved protein content and nutritional quality and directed to its higher general consumer acceptability than cookies formulated with only wheat flour.
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- 2023
7. Potato stillage and sugar beet molasses as a substrate for production of lactic acid and probiotic biomass
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Mladenović Dragana, Pejin Jelena, Kocić-Tanackov Sunčica, Stefanović Andrea, Đukić-Vuković Aleksandra, and Mojović Ljiljana
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lactic acid ,potato stillage ,molasses ,probiotics ,animal feed ,Agriculture - Abstract
Distillery stillage is abundant industrial waste with a great potential for utilization as a substrate in production of valuable bio-based products. Processing of distillery stillage on cost effective way can significantly decrease the price of bioethanol as alternative fuel and provide a considerable benefit to the environment. In this paper, combined potato stillage and sugar beet molasses substrate is evaluated for integrated lactic acid and probiotic biomass production by Lactobacillus rhamnosus ATCC 7469. Waste substrate based on potato stillage and sugar beet molasses enabled lactic acid and biomass production with maximal volumetric lactic acid productivity of 1.11 g L-1 h-1 and maximal number of viable L. rhamnosus ATCC 7469 cells of 1.1×109 CFU mL-1. Residue after removal of lactic acid could be recommended as probiotics and betaine-enriched animal feed.
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- 2016
8. Immobilization of horseradish peroxidase onto kaolin by glutaraldehyde method and its application in decolorization of anthraquinone dye
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Šekuljica Nataša Ž., Prlainović Nevena Ž., Jovanović Jelena R., Stefanović Andrea B., Grbavčić Sanja Ž., Mijin Dušan Ž., and Knežević-Jugović Zorica D.
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horseradish peroxidase ,immobilization ,wastewater ,dyes ,Chemical technology ,TP1-1185 - Abstract
The problem of environmental pollution day by day becomes more worrisome, primarily due to the large amounts of wastewater contaminated with various harmful organic compounds, discharged into the environment untreated or partially clean. Feasibility of use of horseradish peroxidase (Amoracia rusticana) in the synthetic dyes decolorization was approved by many researchers. Among a number of supports used for the immobilization, it was found that natural clay, kaolin has excellent features which are a precondition for obtaining biocatalysts with the excellent performances. For this reason, a horseradish peroxidase was immobilized onto kaolin using glutaraldehyde as a cross-linking agent. Obtained biocatalyst was applied in the decolorization of anthraquinone dye C. I. Acid Violet 109. Under determined optimal conditions (pH 4.0, hydrogen peroxide concentration 0.6 mM, dye concentration 30 mg L-1, temperature 24ºC) around 76 % of dye decolorization was achieved. Reusability study showed that resulting biocatalyst was possible to apply four times in the desired reaction with relatively high decolorization percentage. [Projekat Ministarstva nauke Republike Srbije, br. III-46010 i br. 172013]
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- 2016
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9. Improvement of antioxidant properties of egg white protein enzymatic hydrolysates by membrane ultrafiltration
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Jovanović Jelena R., Stefanović Andrea B., Žuža Milena G., Jakovetić Sonja M., Šekuljica Nataša Ž., Bugarski Branko M., and Knežević-Jugović Zorica D.
- Subjects
antioxidant derived egg white peptides ,membrane ultrafiltration ,ultrasound pretreatment ,hydrolysis ,alcalase ,Chemical technology ,TP1-1185 - Abstract
The production of bioactive peptides from egg white proteins (EWPs) and their separation are emerging areas with many new applications. The objective of this study was to compare antioxidant activity of three distinct EWP hydrolysates and their peptide fractions prepared by membrane ultrafiltration using membranes with 30, 10 and 1 kDa molecular weight cut-off. The hydrolysates were obtained by thermal and ultrasound pretreated EWPs hydrolyzed with a bacterial protease, Alcalase. It appeared that the pretreatment significantly affected peptide profiles and antioxidant activity of the hydrolysates measured by ABTS, DPPH and FRAP methods. The hydrolysate prepared using Alcalase and ultrasound pretreatment at 40 kHz - 15 min has shown to be the most effective in scavenging both DPPH and ABTS radicals (28.10±1.38 and 79.44±2.31%, respectively). It has been noticed that this hydrolysate had a nutritionally more adequate peptide profile than the other hydrolysates with a much lower amount of peptides
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- 2016
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10. Production of egg white protein hydrolysates with improved antioxidant capacity in a continuous enzymatic membrane reactor: optimization of operating parameters by statistical design
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Jakovetić Tanasković, Sonja, Luković, Nevena, Grbavčić, Sanja, Stefanović, Andrea, Jovanović, Jelena, Bugarski, Branko, and Knežević-Jugović, Zorica
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- 2017
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11. Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins
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Stefanović, Andrea B., Jovanović, Jelena R., Dojčinović, Marina B., Lević, Steva M., Nedović, Viktor A., Bugarski, Branko M., and Knežević-Jugović, Zorica D.
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- 2017
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12. Impact of Different Enzymatic Processes on Antioxidant, Nutritional and Functional Properties of Soy Protein Hydrolysates Incorporated into Novel Cookies
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Knežević-Jugović, Zorica, primary, Culetu, Alina, additional, Mijalković, Jelena, additional, Duta, Denisa, additional, Stefanović, Andrea, additional, Šekuljica, Nataša, additional, Đorđević, Verica, additional, and Antov, Mirjana, additional
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- 2022
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13. Immobilization of horseradish peroxidase onto kaolin
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Šekuljica, Nataša Ž., Prlainović, Nevena Ž., Jovanović, Jelena R., Stefanović, Andrea B., Djokić, Veljko R., Mijin, Dušan Ž., and Knežević-Jugović, Zorica D.
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- 2016
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14. Covalent Immobilization of Enzymes on Eupergit® Supports: Effect of the Immobilization Protocol
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Knežević-Jugović, Zorica D., primary, Grbavčić, Sanja Ž., additional, Jovanović, Jelena R., additional, Stefanović, Andrea B., additional, Bezbradica, Dejan I., additional, Mijin, Dušan Ž., additional, and Antov, Mirjana G., additional
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- 2016
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15. Effects of sonication and high-pressure carbon dioxide processing on enzymatic hydrolysis of egg white proteins
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Knežević-Jugović Zorica D., Stefanović Andrea B., Žuža Milena G., Milovanović Stoja L., Jakovetić Sonja M., Manojlović Verica B., and Bugarski Branko M.
- Subjects
Egg white proteins ,alcalase ,antioxidant activity ,ultrasound pretreatment ,high-pressure carbon dioxide processing ,Technology (General) ,T1-995 - Abstract
The objectives of this study were to examine the effect of sonication and high-pressure carbon dioxide processing on proteolytic hydrolysis of egg white proteins and antioxidant activity of the obtained hydrolysates. It appeared that the ultrasound pretreatment resulted in an increase in the degree of hydrolysis of the enzymatic reaction while the high-pressure carbon dioxide processing showed an inhibition effect on the enzymatic hydrolysis of egg white proteins to some extent. The antioxidant activity of the obtained hydrolysates was improved by ultrasound pretreatment of egg white proteins at the pH 8.3. Thus, the combination of ultrasound pretreatment at the pH 8.3 and subsequent enzymatic hydrolysis with alcalase at 50°C and pH 8.0 could offer a new approach to the improvement of the functional properties of egg white proteins and their biological activity. [Projekat Ministarstva nauke Republike Srbije, br. E!6750]
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- 2012
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16. Impact of ultrasound on egg white proteins as a pretreatment for functional hydrolysates production
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Stefanović, Andrea B., Jovanović, Jelena R., Grbavčić, Sanja Ž., Šekuljica, Nataša Ž., Manojlović, Verica B., Bugarski, Branko M., and Knežević-Jugović, Zorica D.
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- 2014
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17. An approach for the improved immobilization of penicillin G acylase onto macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) as a potential industrial biocatalyst
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Knežević-Jugović, Zorica D., žuža, Milena G., Jakovetić, Sonja M., Stefanović, Andrea B., Džunuzović, Enis S., Jeremić, Katarina B., and Jovanović, Slobodan M.
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- 2016
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18. Extraction of phenolic compounds from agro-industrial wastes and evaluation of their antioxidative potential
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Jovanović, Jelena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, Gazikalović, Ivana, Stefanović, Andrea, Grbavčić, Sanja, Luković, Nevena, Knežević-Jugović, Zorica, Jovanović, Jelena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, Gazikalović, Ivana, Stefanović, Andrea, Grbavčić, Sanja, Luković, Nevena, and Knežević-Jugović, Zorica
- Abstract
Constant world population growth imposes the need for the production of more food, and as a consequence, has an increase in the organic-rich wastes. These agro-industrial wastes represent problem from the environmental viewpoint, and their utilization as the raw materials for the production of value-added products has become one of the main topics of the biorefinery. The aim of this research was to use soybean meal, co-product of dietary oil production, as a model agro-industrial by-product for optimization of phenolic compounds extraction. In this paper, ethanol influenced microwave-assisted extraction is chosen since it is recognized as eco-friendly and food-safe. Optimization of the extraction included finding the optimal liquid/solid ratio, extraction duration, and microwave power. The same method was applied for the extraction of phenolics from apple pomace, apple pomace mixed with soybean meal, ultrasound-treated soybean meal, and wheat bran. Antioxidative potential of all extracts was evaluated using a fixed reaction time 2,2-diphenyl-1-picrylhydrazyl (DPPH) method as well as a steady-state measurement DPPH method. 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) i.e., ABTS and ferric reducing antioxidant power (FRAP) methods were applied as well. Under optimized conditions (liquid/solid ratio of 15 mL/g for 70 s at a microwave power of 300 W) 3.87 mg gallic acid equivalent (GAE)/g was extracted from soybean meal, which represented a substantial increase compared to 2.46 mg GAE/g obtained before optimization. Results showed that extracts had different behavior towards different radicals depending on the type of the extracted phenolics. Apple pomace extract was the most potent towards DPPH• radical, while the most effective extract towards ABTS•+ radical was obtained from apple pomace and soybean meal mixture. The soybean meal extract showed the highest reducing power assessed via the FRAP method. Results obtained in this study show that optimization of
- Published
- 2021
19. Extraction of phenolic compounds from agro-industrial wastes and evaluation of their antioxidative potential
- Author
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Jovanović, Jelena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, Gazikalović, Ivana, Stefanović, Andrea, Grbavčić, Sanja, Luković, Nevena, Knežević-Jugović, Zorica, Jovanović, Jelena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, Gazikalović, Ivana, Stefanović, Andrea, Grbavčić, Sanja, Luković, Nevena, and Knežević-Jugović, Zorica
- Abstract
Constant world population growth imposes the need for the production of more food, and as a consequence, has an increase in the organic-rich wastes. These agro-industrial wastes represent problem from the environmental viewpoint, and their utilization as the raw materials for the production of value-added products has become one of the main topics of the biorefinery. The aim of this research was to use soybean meal, co-product of dietary oil production, as a model agro-industrial byproduct for optimization of phenolic compounds extraction. In this paper, ethanol influenced microwave-assisted extraction is chosen since it is recognized as eco-friendly and food-safe. In this paper, we used soybean meal, co-product of dietary oil production, as a model agro-industrial by-product for optimization of phenolic compounds extraction. Ethanol influenced microwave-assisted extraction is chosen since it is recognized as eco-friendly and food-safe. Optimization of the extraction included finding the: optimal liquid/solid ratio, extraction duration, and microwave power. The same method was applied for the extraction of phenolics from apple pomace, apple pomace mixed with soybean meal, ultrasound-treated soybean meal, and wheat bran. Antioxidative potential of all extracts was evaluated using a fixed reaction time 2,2-diphenyl-1- picrylhydrazyl (DPPH) method as well as a steady-state measurement DPPH method. 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) i.e., ABTS and ferric reducing antioxidant power (FRAP) methods were applied as well. Under optimized conditions (liquid/solid ratio of 15 mL/g for 70 s at a microwave power of 300 W) 3.87 mg gallic acid equivalent (GAE)/g was extracted from soybean meal, which represented a substantial increase compared to 2.46 mg GAE/g obtained before optimization. Results showed that extracts had different behavior towards different radicals depending on the type of the extracted phenolics. Apple pomace extract was the most potent towa
- Published
- 2020
20. Enzymatic treatment of soy protein concentrate: Influence on the potential techno-functional and antioxidant properties
- Author
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Jovanović, Jelena, Stefanović, Andrea, Culetu, Alina, Duta, Denisa, Luković, Nevena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, Knežević-Jugović, Zorica, Jovanović, Jelena, Stefanović, Andrea, Culetu, Alina, Duta, Denisa, Luković, Nevena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, and Knežević-Jugović, Zorica
- Abstract
In recent years, there has been an unprecedented de-mand by both consumers and industry, for inexpensive plant-derived protein hydrolysates as potential dietary sources of antioxidants. This is a particular refers to the protein from agricultural crop, such as soybean flour and/or flakes, especially from the soy protein concentrate (SPC). However, insolubility of SPC in water limits its more extensive use as food-protein ingredient, but it can be overcome by applying various enzymatic and non-enzymatic treatments. In order to expand the application of SPC, the influence of the one-step enzyme modification by using the commercial food-grade en-doprotease from Bacillus licheniformis on the antiox-idant and functional properties has been considered. For this purpose, SPC under the various dry matter contents (DM) were pre-incubated at the optimal temperature and hydrolyzed in a mechanically stirred batch reactor. The bioactivity was evaluated using rad-ical-scavenging and metal-chelating assays. The ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sul-phonic acid)) radical-scavenging ability reached higher values at DM 8% and smaller hydrolysis degree (DH) 12.85%, then a decreasing for higher DH and the minimum reducing power was observed after hydrolysis of SPC with DM 2% and DH~18% (64.2%). It appeared that the all prepared hydrolysates had the high yields of bioactive peptides which had the ability to strong-ly chelating prooxidant ferrous metal ions ( gt 95%). The techno-functionalities of SPC hydrolysate (DM 8%) with relatively higher antioxidant activities were remarkably higher compared to the untreated SPC. Namely, this hydrolysate had excellent solubility over a pH range of 2-12 which was improved compared to untreated SPC-8%. The oil holding capacity was also enhanced, while enzyme treatment was damaging to both of emulsifying properties, activity and stability, and water holding capacity. The results obviously show that enzyme treated SPCs were superior to the
- Published
- 2020
21. Modification of emulsifying properties and metal-ion chelating ability of gluten hydrolysates by partial enzymatic hydrolysis
- Author
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Jovanović, Jelena, Stefanović, Andrea, Šekuljica, Nataša, Gazikalović, Ivana, Luković, Nevena, Jakovetić Tanasković, Sonja, and Knežević-Jugović, Zorica
- Subjects
Optimization ,Enzymatic hydrolysis ,Wheat gluten protein ,Emulsification activity ,Emulsification stability ,Experimental design ,Metal-ion chelating ability - Abstract
Wheat gluten represents the major protein fraction present in wheat flour and as protein-rich material posses cohesive and viscoelastic properties which permit the retention of gas bubbles in the dough. It could be obtained as a by-product during the separation of starch from wheat flour and as such may be utilized like a functional protein additive in various non-bakery foodstuffs due to its desirable structure-enhancing properties. However, wheat gluten is hardly soluble in water, which limits their expanding utilization. In the regard, the aim of this research was to investigate the correlation between process parameters of wheat gluten hydrolysis and emulsification activity and stability of the prepared hydrolysates. The hydrolysates showing the greatest enhancement of the emulsifying properties which are closed correlated with solubility improvement was further separated by sequential ultrafiltration to obtain molecular weight distribution profile and peptide fraction with higher metal-ion chelating ability. The hydrolysis was performed by using commercial endopeptidase from Bacillus licheniformis and process was followed by monitoring the degree of hydrolysis, emulsifying properties and metal-ion chelating activity. The effects of some relevant process parameters such as gluten concentration (1-9% w/v), temperature (40-60 °C), pH (7-9), enzyme/substrate ratio (0.25-0.75 AU g-¹ of protein) and their interactions were investigated by the means of the four-factor Box-Behnken experimental design with 29 experimental points (5 central points). The obtained results showed that the second-order models developed for emulsification activity and stability of gluten hydrolysates were significant (p
- Published
- 2019
22. Enzymatic treatment of soy protein concentrate: Influence on the potential techno-functional and antioxidant properties
- Author
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Jovanović, Jelena, Stefanović, Andrea, Culetu, Alina, Duta, Denisa, Luković, Nevena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, Knežević-Jugović, Zorica, Jovanović, Jelena, Stefanović, Andrea, Culetu, Alina, Duta, Denisa, Luković, Nevena, Jakovetić Tanasković, Sonja, Šekuljica, Nataša, and Knežević-Jugović, Zorica
- Abstract
In recent years, there has been an unprecedented de-mand by both consumers and industry, for inexpensive plant-derived protein hydrolysates as potential dietary sources of antioxidants. This is a particular refers to the protein from agricultural crop, such as soybean flour and/or flakes, especially from the soy protein concentrate (SPC). However, insolubility of SPC in water limits its more extensive use as food-protein ingredient, but it can be overcome by applying various enzymatic and non-enzymatic treatments. In order to expand the application of SPC, the influence of the one-step enzyme modification by using the commercial food-grade en-doprotease from Bacillus licheniformis on the antiox-idant and functional properties has been considered. For this purpose, SPC under the various dry matter contents (DM) were pre-incubated at the optimal temperature and hydrolyzed in a mechanically stirred batch reactor. The bioactivity was evaluated using rad-ical-scavenging and metal-chelating assays. The ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sul-phonic acid)) radical-scavenging ability reached higher values at DM 8% and smaller hydrolysis degree (DH) 12.85%, then a decreasing for higher DH and the minimum reducing power was observed after hydrolysis of SPC with DM 2% and DH~18% (64.2%). It appeared that the all prepared hydrolysates had the high yields of bioactive peptides which had the ability to strong-ly chelating prooxidant ferrous metal ions ( gt 95%). The techno-functionalities of SPC hydrolysate (DM 8%) with relatively higher antioxidant activities were remarkably higher compared to the untreated SPC. Namely, this hydrolysate had excellent solubility over a pH range of 2-12 which was improved compared to untreated SPC-8%. The oil holding capacity was also enhanced, while enzyme treatment was damaging to both of emulsifying properties, activity and stability, and water holding capacity. The results obviously show that enzyme treated SPCs were superior to the
- Published
- 2019
23. Enzymatic hydrolysis as a tool for enhancing antioxidant capacity and sensory qualities of soy proteins
- Author
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Knežević-Jugović, Zorica, Culetu, Alina, Duta, Denisa, Mohan, Gabriela, Jovanović, Jelena, Stefanović, Andrea, Šekuljica, Nataša, and Đorđević, Verica
- Subjects
Optimization ,Enzymatic hydrolysis ,Soy proteins ,Bioactive peptides ,Antioxidant capacity ,Sensory quality - Abstract
Introduction: Soy proteins are widely used in several food products in the forms of soy flour, soy protein concentrate (SPC) and soy protein isolate (SPI) to improve water and fat binding ability and improve nutritional content. Recent research efforts in this field continue to look at novel functional properties of soy proteins through physical, chemical or enzymatic modifications [1]. Although it has been demonstrated that the enzymatic hydrolysis of SPI is a suitable route to improve its antioxidant properties, there is a general lack of knowledge about the potential for beneficial effects of protease hydrolysis on soy products other than SPI, such as soy flour or SPC. The aim of this study was to investigate the antioxidant activities, and color of spray-dried hydrolysates of SPC obtained with several proteases. Materials and methods: A commercial SPC (protein content 71.24%) was a gift from the SOJAPROTEIN, Bečej. The proteases used were: alcalase® 2.4L, neutrase® 0.8L, papain, everlase 16.0 L (Sigma) and umamizyme (Amano Enzyme Inc). The antioxidant activity was tested by using several methods: DPPH, ABTS, and linoleic acid emulsion system [2]. Results: Process parameters like substrate concentration, E/S ratio, temperature, and DH have been optimized for each selected enzyme or their combination. The five proteolytic enzymes used for hydrolysis of SPC led to different reaction kinetics resulting also in different peptide profiles determined by gel filtration chromatography using Sephadex G-50. Conclusions: The alcalase hydrolysate seemed to be the most effective antioxidant determined by DPPH, ABTS, and linoleic acid emulsion system assays. The enzymatic hydrolysis in all cases resulted in an increase in the antioxidant activity of hydrolysate and all hydrolysates showed significantly changed color compared to SPC.
- Published
- 2018
24. Influence of soy protein hydrolysates on the rheological characteristics of wheat dough
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Culetu, Alina, Duta, Denisa, Knežević-Jugović, Zorica, Jovanović, Jelena, Šekuljica, Nataša, and Stefanović, Andrea
- Subjects
Wheat dough ,Rheological characteristics ,Soy protein hydrolysates ,Mixolab ,Protease - Abstract
The use of protein hydrolysates in bakery products is gaining importance due to the presence of bioactive peptides in their composition. Soy protein hydrolysates (SPHs) have gained interest due to the lack of antinutritional factors and presence of various bioactivities (antioxidant activity, cholesterol-lowering activity or immunoregulatory properties). The aim of the study was to evaluate the dough rheology parameters of wheat flour replaced by 5% withdifferent SPHs. SPHs were obtained by enzymatic hydrolysis of soy protein concentrate with different proteases: Alcalase® 2.4L, Everlase 16.0L, Neutrase® 0.8L, Papain and Umamizyme. The rheological behavior of flour mixtures was evaluated using a Mixolab analyzer (Chopin Technologies) with the “Chopin+” protocol. The SPHaddition in the wheat flour resulted in decreases in water absorption with almost 3.9% as compared with control dough. Dough development time increased with SPH addition, with the highest value registered for umamizyme hydrolysate (5.9 min towards 1.4 min for control). Thus, SPHs prevented gluten network development.Stability and C2 value (which represents the beginning of the protein destabilization and unfolding) decreased with the SPH addition in the dough formulation, which proves the weakening of the gluten network. In the same trend, starch gelatinization (C3), stability of the starch gel (C4) as well as starch retrogradation (C5) were reduced by the addition of SPHs. These values were decreased in the order: control > alcalase ≈ everlase ≈ umamizyme > neutrase > papain. In conclusion, dough characteristics provided by Mixolab are the results of the interaction of SPHs components with the flour constituents.Papain hydrolysate could contribute to the increase of the shelf-life of bakery products.
- Published
- 2018
25. Production of wheat gluten hydrolysates with improved functional properties: Optimization of operating parameters by statistical design
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Jovanović, J., Stefanović, Andrea, Šekuljica, Nataša, Knežević-Jugović, Zorica, Jovanović, J., Stefanović, Andrea, Šekuljica, Nataša, and Knežević-Jugović, Zorica
- Abstract
Native wheat gluten is a deluxe bread improver and may be utilized as a functional protein additive in multifarious non-bakery foodstuffs due to its desirable structure-enhancing properties. Also its utilization would be economically interesting, but lack of some desirable functional properties limited their expanding utilization in foodstuff formulations. This study was designed to examine the relationship between process parameters and functional properties of the obtained hydrolysates using Box-Benken experimental design and response surface methodology (RSM). The hydro-lysate showing the highest improvement of solubility and foaming ability was further separated by sequential ultrafiltration to obtain molecular weight distribution profile. The progress of wheat gluten hydrolysis was followed by monitoring the degree of hydrolysis (DH) using the pH-stat method and functional properties were measured by our methods already adopted. The effects of process parameters (pH, T, [S], [E]/[S] ration) and their interactions were investigated by the means of the four-factor Box-Behnken experimental design with 29 experimental points (5 central points). Experiments were carried out in triplicates and expressed as means with SD. The effects of different parameters under the significance level of p < 0.05 were examined using one-way analysis of variance (ANOVA) and Student t-test. The coefficients of the response function and their statistical significance were evaluated by the response surface regression analysis, using the Design software. Non-significant terms (p ≥ 0.05) were deleted from the second order polynomial and a new polynomial has been recalculated. The Fisher test (F-value) was used to determine whether the second-order model was adequate to describe the obtained data while the goodness of fit of the model was evaluated by the determination coefficient (R2). The obtained results showed that the second-order models developed for DH, solubility and foaming prop
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- 2018
26. Production of egg white protein hydrolysates with improved antioxidant capacity in a continuous enzymatic membrane reactor: optimization of operating parameters by statistical design
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Jakovetić Tanasković, Sonja, Luković, Nevena, Grbavčić, Sanja, Stefanović, Andrea, Jovanović, Jelena, Bugarski, Branko, Knežević-Jugović, Zorica, Jakovetić Tanasković, Sonja, Luković, Nevena, Grbavčić, Sanja, Stefanović, Andrea, Jovanović, Jelena, Bugarski, Branko, and Knežević-Jugović, Zorica
- Abstract
This study focuses on the influence of operating conditions on Alcalase-catalyzed egg white protein hydrolysis performed in a continuously stirred tank reactor coupled with ultrafiltration module (10 kDa). The permeate flow rate did not significantly affect the degree of hydrolysis (DH), but a significant increase in process productivity was apparent above flow rate of 1.9 cm(3) min(-1). By contrast, an increase in enzyme/substrate (E/S) ratio provided an increase in DH, but a negative correlation was observed between E/S ratio and productivity. The relationship between operating conditions and antioxidant properties of the hydrolysates, measured by three methods, was studied using Box-Behnken experimental design and response surface methodology. The statistical analysis showed that each variable (impeller speed, E/S ratio, and permeate flow rate) had a significant effect on the antioxidant capacity of all tested systems. Nevertheless, obtained response functions revealed that antioxidative activity measured by DPPH, ABTS and FRAP methods were affected differently by the same operating conditions. High impeller speeds and low permeate flow rates favor ABTS while high impeller speeds and high permeate flow rates had a positive effect on the DPPH scavenging activity. On the other hand, the best results obtained with FRAP method were achieved under moderate operating conditions. The integration of the reaction and ultrafiltration membrane separation in a continuous manner appears to be a right approach to improve and intensify the enzymatic process, enabling the production of peptides with desired antioxidant activity.
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- 2018
27. Influence of ultrasound probe treatment time and protease type on functional and physicochemical characteristics of egg white protein hydrolysates
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Stefanović, Andrea, Jovanović, Jelena, Balanč, Bojana, Šekuljica, Nataša, Jakovetić Tanasković, Sonja, Dojčinović, Marina, Knežević-Jugović, Zorica, Stefanović, Andrea, Jovanović, Jelena, Balanč, Bojana, Šekuljica, Nataša, Jakovetić Tanasković, Sonja, Dojčinović, Marina, and Knežević-Jugović, Zorica
- Abstract
The objective of this study was to discover the relationship between the ultrasound probe treatment (UPT) on egg white proteins (EWPs) before EWPs hydrolysis by different proteases, and the functional properties of the obtained hydrolysates. To fulfill this goal, the protein solubility, foaming, and emulsifying properties were studied as a function of the UPT time and then related to the surface characteristics and structural properties. The changes in the hydrolysates microstructures and macromolecular conformation, induced by the UPT, were followed using scanning electron microscope analyzis (SEM) and Fourier transforms infrared spectroscopy (FTIR). The results showed that UPT influenced (P lt 0.05) the proteolysis of egg white proteins for all examined treatment times. Alcalase hydrolysates (AHs) and papain hydrolysates (PHs) were found to have a higher solubility, as a consequence of their relatively higher foaming, and emulsifying properties compared to the untreated hydrolysates. The changes in surface hydrophobicity, sulfhydryl content and surface charge of AHs and PHs indicated unfolding of EWPs affected by ultrasound. SEM analyzis showed that UPT destroyed the microstructures of AHs and PHs, while FTIR spectra indicated remarkable changes in the macromolecular conformation of AHs and PHs after UPT. This study revealed that by combining ultrasound pre-hydrolysis treatment under controlled conditions with thoughtful proteases selection, hydrolysates with improved functional properties could be produced, enhancing utilization of EWPs in food products.
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- 2018
28. Production of wheat gluten hydrolysates with improved functional properties: optimization of operating parameters by statistical design
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Jovanović, Jelena, Stefanović, Andrea, Šekuljica, Nataša, Knežević-Jugović, Zorica, Jovanović, Jelena, Stefanović, Andrea, Šekuljica, Nataša, and Knežević-Jugović, Zorica
- Abstract
Introduction: Native wheat gluten is a deluxe bread improver and may be utilized as a functional protein additive in multifarious nonbakery foodstuffs due to its desirable structure-enhancing properties. Also its utilization would be economically interesting, but lack of some desirable functional properties limited their expanding utilization in foodstuff formulations [1]. This study was designed to examine the relationship between process parameters and functional properties of the obtained hydrolysates using Box-Benken experimental design and response surface methodology (RSM). The hydrolysate showing the highest improvement of solubility and foaming ability was further separated by sequential ultrafiltration to obtain molecular weight distribution profile. Materials and methods: The progress of wheat gluten hydrolysis was followed by monitoring the degree of hydrolysis (DH) using the pH-stat method and functional properties were measured by our methods already adopted [2]. The effects of process parameters (pH, T, [S], [E]/[S] ration) and their interactions were investigated by the means of the four-factor Box-Behnken experimental design with 29 experimental points (5 central points). Results: The obtained results showed that the second-order models developed for DH, solubility and foaming properties of gluten hydrolysates were significant (p<0.05) with a high value of coefficients of determination (0.944-0.981). The statistical analysis showed that each variable had a significant effect on degree of hydrolysis and the functional properties of tested system. Almost the linear increase in DH was observed with the rise in temperature at the highest substrate concentration, while on the other hand increasing the concentration of the substrate leads to a decrease in DH. In terms of foaming properties results showed that foam capacity range are in the range of 24.2- 80.3%, depending on the independent variables that were tested. Conclusions: Results are relevant to th
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- 2018
29. Optimization of enzymatic processes in order to obtain egg white protein hydrolysates as a functional food component applying the high-intensity ultrasound technology
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Stefanović, Andrea B., Knežević-Jugović, Zorica, Bugarski, Branko, Rakin, Marica, Antov, Mirjana, and Grbavčić, Sanja
- Subjects
technological-functional properties ,tehnološko-funkcionalna svojstva ,ultrazvučni pretretman ,egg white proteins ,enzymatic hydrolysis ,enzimska hidroliza ,strukturna karakterizacija ,ultrasound treatment ,proteini belanceta ,structural characterization - Abstract
Predmet naučnog istraţivanja doktorske disertacije je razvoj novih netermičkih i enzimskih procesa za proizvodnju proteina belanceta i njihovih hidrolizata sa unapreĎenim tehnološko-funkcionalnim svojstvima kao visokokvalitetnih proteinskih dodataka hrani i napicima... The scope of this academic doctoral research is the development of new non-thermal and enzymatic processes in order to obtain high-qualitiy egg white protein and their hydrolysates with improved technological-functional properties as high-quality protein additives for food and beverages...
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- 2017
30. Enhancing protein release and functionality of soy proteins from defatted soy flakes using high-intensity ultrasound-assisted extraction
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Stefanović, Andrea, Jovanović, Jelena, Stojaković, Sanja, Jugović, Branimir, Bugarski, Branko, and Knežević-Jugović, Zorica
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Soy proteins ,Solubility ,Sulfhydryl content ,Ultrasound probe extraction - Abstract
In addition to evidence regarding their potential for inclusion into functional foods, the effect of the high-intensity ultrasound extraction (HIUE) on the functional properties of soy proteins will be discussed. The aim of this study was to examine the effects of HIUE as a function of the treatment time and ultrasound amplitude, in order to obtain better understanding of physicochemical effects of HIUE on soy protein which may lead to improving its applications in the food industry. For this purpose, samples of the yellow defatted soybean (Glycine max) variety Laura were treated with ultrasound probe system (20±0.2 kHz) by varying the treatment time (30 s, 2, 5, 10, 15 min) and an amplitude (15% and 30%). Functional properties of the obtained samples were characterized in terms of solubility and sulfhydryl content. HIUE resulted in a slight, but gradual decline in solubility with a treatment time, but significant increase (p < 0.05) in acidic environment was observed with the increase of ultrasound amplitude. Sulfhydryl content has been greater influenced with a treatment time for both amplitude applied. The results show that the ultrasound extracted soy proteins were superior to the original (untreated) in the functional properties tested and can be concluded that by combining the treatment time and the ultrasonic power, the samples with enhanced functionalities can be produced enhancing utilization of soy proteins in food products.
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- 2017
31. Covalent immobilization of enzymes on Eupergit® supports: Effect of the immobilization protocol
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Knežević-Jugović, Zorica, Grbavčić, Sanja, Jovanović, Jelena, Stefanović, Andrea, Bezbradica, Dejan, Mijin, Dušan, and Antov, Mirjana
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Glycoenzymes ,Aminated support ,Multipoint covalent attachment ,Periodate oxidation ,Epoxy groups ,Enzyme chemical amination ,Eupergit C ,Carbodiimide chemistry ,Covalent immobilization - Abstract
A selection of best combination of adequate immobilization support and efficient immobilization method is still a key requirement for successful application of immobilized enzymes on an industrial level. Eupergit® supports exhibit good mechanical and chemical properties and allow establishment of satisfactory hydrodynamic regime in enzyme reactors. This is advantageous for their wide application in enzyme immobilization after finding the most favorable immobilization method. Methods for enzyme immobilization that have been previously reported as efficient considering the obtained activity of immobilized enzyme are presented: direct binding to polymers via their epoxy groups, binding to polymers via a spacer made from ethylene diamine/glutaraldehyde, and coupling the periodate-oxidized sugar moieties of the enzymes to the polymer beads. The modification of the conventionally immobilized enzyme with ethylenediamine via the carbodiimide route seems to be a powerful tool to improve its stability and catalytic activity.
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- 2017
32. Optimizacija enzimskih postupaka za dobijanje hidrolizata proteina belanceta kao komponenata funkcionalne hrane primenom tehnologije ultrazvuka visokog intenziteta
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Knežević-Jugović, Zorica, Bugarski, Branko, Rakin, Marica, Antov, Mirjana, Grbavčić, Sanja, Stefanović, Andrea B., Knežević-Jugović, Zorica, Bugarski, Branko, Rakin, Marica, Antov, Mirjana, Grbavčić, Sanja, and Stefanović, Andrea B.
- Abstract
Predmet naučnog istraţivanja doktorske disertacije je razvoj novih netermičkih i enzimskih procesa za proizvodnju proteina belanceta i njihovih hidrolizata sa unapreĎenim tehnološko-funkcionalnim svojstvima kao visokokvalitetnih proteinskih dodataka hrani i napicima..., The scope of this academic doctoral research is the development of new non-thermal and enzymatic processes in order to obtain high-qualitiy egg white protein and their hydrolysates with improved technological-functional properties as high-quality protein additives for food and beverages...
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- 2017
33. Effect of the Controlled High-Intensity Ultrasound on Improving Functionality and Structural Changes of Egg White Proteins
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Stefanović, Andrea, Jovanović, Jelena, Dojčinović, Marina, Lević, Steva, Nedović, Viktor, Bugarski, Branko, Knežević-Jugović, Zorica, Stefanović, Andrea, Jovanović, Jelena, Dojčinović, Marina, Lević, Steva, Nedović, Viktor, Bugarski, Branko, and Knežević-Jugović, Zorica
- Abstract
The objective of this research was to investigate the impact of high-intensity ultrasound (HIU) generated by a probe-type sonicator (frequency 20 +/- 0.2 kHz and an amplitude of 40%) for 2-20 min on the selected functional and structural properties of egg white proteins (EWPs) and their susceptibility to hydrolysis by alcalase. The protein solubility, foaming, and emulsifying properties were studied as a function of ultrasonication time and related to protein particle and structural properties. The length of ultrasonication exhibited important effect on EWP particle size, uniformity, and charge, affecting also the protein conformation and susceptibility to alcalase hydrolysis and determining functional properties. There was a linear correlation between the particle size decrease and the solubility while a two-step linear correlation between the foam capacity (FC)/foam stability (FS) and particle size was apparent. Specifically, FC and FS sharply increased with decreasing particle size for range from similar to 370 to similar to 260 nm, and below this range from 260.6 to 68.4 nm, the changes were not that substantial. Besides, the solubility, FC, and FS were directly and linearly related with the absolute value of the particle zeta potential. The overall emulsifying properties were also improved with an increase of sonication time, through both the decrease of the mean particle diameter and the increase of zeta potential, but there was no direct correlation between the emulsion activity/stability index and protein particle size and/or charge. Analysis of EWP structure by Raman spectroscopy revealed that the HIU leads to changes in the secondary structure, while heat and ultrasound generated by the ultrasound bath were not sufficient to exhibit this effect.
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- 2017
34. The synergistic effect of heat treatment on alcalase-assisted hydrolysis of wheat gluten proteins: Functional and antioxidant properties
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Elmalimadi, Mohamed B., Stefanović, Andrea, Šekuljica, Nataša, Žuža, Milena, Luković, Nevena, Jovanović, Jelena, Knežević-Jugović, Zorica, Elmalimadi, Mohamed B., Stefanović, Andrea, Šekuljica, Nataša, Žuža, Milena, Luković, Nevena, Jovanović, Jelena, and Knežević-Jugović, Zorica
- Abstract
In order to confirm the gluten potential for inclusion into functional foods, the synergistic effect of the heat treatment and controlled enzymatic hydrolysis on the functional and the antioxidant properties of alcalase-assisted wheat gluten hydrolysates (AWGHs) will be discussed. For this purpose, wheat gluten was heat-treated during 30min at 75 degrees C and intensively hydrolyzed with alcalase at degree of hydrolysis (DH) 16.1%, 22.9%, and 30.2%. All the hydrolysates had excellent solubility over a pH range of 2-12. Emulsifying activity and stability were also improved, while proteolysis was deleterious to foam capacity and stability, water-holding capacity, fat-binding capacity and did not show improvement at higher DH (22.9% and 30.2%). As well, controlled hydrolysis of heat-treated gluten resulted in a remarkable improvement in antioxidant activities. The results show that the heat-treated AWGHs were superior to the untreated hydrolysate in the functional and antioxidant properties tested. Practical applicationsThis report examines existing evidence regarding the wheat gluten proteins (WGP), which is a byproduct from wheat starch processing. It is known that enzymatic hydrolysis is frequently used to improve functional properties of protein hydrolysates and largely dependent on the degree of hydrolysis (DH), which needs to be controlled to elude redundant proteolysis that can deteriorate functionality and cause unfavorable effects. The DH is a substantial factor which affect the hydrolysates' performances and an appropriate selection of protease for WGP hydrolysis will result in maximum biological activity and improved functionalities. Heat treatment is often used to facilitate the proteolysis of proteins. Thus, functional and antioxidant properties of WGP hydrolysates, as a function of heat treatment and the DH were adequately examined in this study and results showed that by combining heat prehydrolysis treatment under controlled conditions, hydrolysates wit
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- 2017
35. Antioxidant properties of hydrolysates of wheat gluten as influenced by process conditions
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Knežević-Jugović, Zorica, Elmalimadi, Mohamed B., Stefanović, Andrea, Jovanović, Jelena, Jakovetić Tanasković, Sonja, Bugarski, Branko, Knežević-Jugović, Zorica, Elmalimadi, Mohamed B., Stefanović, Andrea, Jovanović, Jelena, Jakovetić Tanasković, Sonja, and Bugarski, Branko
- Abstract
The effects of some relevant process parameters for the Alcalase-catalyzed wheat gluten hydrolysis such as gluten concentration (X1; 1-9% w/v), temperature (X2; 40-60 oC), pH (X3; 7-9) and enzyme/substrate ratio, [E]/[S] ratio (X4; 0.25– 0.75 AU/g of protein) were investigated by the means of an experimental design. The second-order models developed for the degree of hydrolysis, DH, DPPH and ABTS radical scavenging activity of gluten hydrolysates were significant (p<0.01) with a high value of coefficients of determination (0.981-0.992). The statistical analysis showed that each variable had a significant effect on degree of hydrolysis and the antioxidant capacity of both tested systems. Hydrolysis up to around DH = 15% improved DPPH radical scavenging activity, while excessive hydrolysis worsened it. It seemed there was not a correspondence between degree of hydrolysis and ABTS activity at different protein concentrations, suggesting that there were peptides with considerable size presenting a good antioxidant capacity.
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- 2017
36. Structural and functional characterization of papain-assisted ultrasound pretreated egg white hydrolysis
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Stefanović, Andrea, Jovanović, Jelena, Šekuljica, Nataša, Grbavčić, Sanja, Luković, Nevena, Bugarski, Branko, and Knežević-Jugović, Zorica
- Subjects
Functional properties ,Proteolysis ,Ultrasound pretreatment ,Egg white proteins ,Structural characterization - Abstract
The main objective of this research is to quantitatively investigate the impact of high intensity ultrasound waves generated by probe-type sonicator on the selected functional and structural properties of papainassisted egg white protein hydolysis (PEWPHs). As well, the effect of pretreatment time on the susceptibility to proteolysis was investigated. 10 % (w/w) aqueous solution of egg white proteins (EWPs) was sonicated at an actual ultrasonic power of 30.7 W. The trials have been accomplished using the modified vibratory cavitation test set up source at resonant frequency of 20 ± 0.2 kHz during the different pretreatment time (2, 5, 10, 15 and 20 minutes). The functional properties of the PEWPHs were probed in terms of solubility, digestibility and foaming ability. In order to understand the molecular structure and morphology of ultrasound pretreated EWPs, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and scanning electron microscopy (SEM) were employed to image the materials. The performance of ultrasound PEWPHs were compared to their untreated counterparts. The proteolytic pattern of papain-assisted EWP hydrolysis was significantly improved for all pretreatment time applied, but the prolonged exposure to ultrasound of 20 min seemed to have a negative effect on the EWPs hydrolysis. The treatment of the EWPs during 5 min can be adopted as the optimal for PEWPHs. Ultrasound pretreatment seemed to increase solubility and digestibility and also caused enhanced foaming properties of PEWPHs compared to the control (untreated EWPs). It was found that particle morphology (SEM images) of PEWPHs were completely different and the less small particles were trapped in large dents of large particles and narrow range of particle size was observed for ultrasound pretreated PEWPHs. SDS-PAGE patterns affected on the release some small peptides (< 14.4 kDa) causing a significant decrease in molecular weight of ultrasound pretreated PEWPHs. The outcomes presented here suggest that the application of the probe-type sonicator have na important role in the improvement of functional and structural properties of PEWPHs and the combined ultrasound pretreatment and enzymatic hydrolysis, not only represents a rapid, efficient and reliable alternative to improve the quality of EWPs, but it also has the potential to develop new products with a unique functionality.
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- 2016
37. Oksidacija antrahinonskih boja peroksidazom iz rena imobilisanom u obliku umreženih enzimskih agregata
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Šekuljica, Nataša, Prlainović, Nevena, Stefanović, Andrea, Jovanović, Jelena, Jakovetić, Sonja, Knežević-Jugović, Zorica, and Mijin, Dušan
- Subjects
anthraquinone dye ,imobilizacija ,horseradish peroxidase ,antrahinonske boje ,immobilization ,peroksidaza iz rena ,umreženi enzimski agregati ,wastewater ,otpadne vode ,cross-linked enzyme aggregates - Abstract
Finding a sustainable and ecofriendly methods for recalcitrant synthetic dyes removal is a researchers major challenge. A carrier-free technique for commercial HRP immobilization is a focus of the present study. The immobilized biocatalyst, HRP-CLEAs with 580 U g-1 of the activity was obtained under the following immobilization conditions: precipitation reagent 80% ammonium sulphate, cross-linking reagent 1% of glutaraldehyde and protein-fedder, bovine serum albumin (BSA) concentration 5 mg ml-1. The obtained HRP-CLEAs showed great affinity towards model anthraquinone dye, C. I. Acid Violet 109. 88.4% of the dye was oxidized under the reaction conditions: pH 4, dye concentration 40 mg l-1, H2O2 concentration 1 mM and 0.1 U of HRP-CLEAs. The possibility of the immobilized biocatalyst application in five and eight oxidation cycles of the dye and pyrogallol (retained activity 80%), respectively, indicates that HRP-CLEAs is an efficient and environmentally friendly biocatalyst with great potential in aromatic compounds removal from wastewater. This paper is a continuation of our earlier research related to HRP from horseradish extract immobilization in the form of CLEAs and the application in the wastewater colored with a synthetic anthraquinone dye treatment. Pronalazak održivih i ekološki prihvatljivih metoda za uklanjanje sintetičkih boja je jedan od vodećih izazova za istraživače. U ovom radu akcenat je na metodi imobilizacije bez primene nosača. Imobilisani preparat peroksidaze iz rena, aktivnosti 580 U g-1 dobijen je pod sledećim uslovima imobilizacije: taložni reagens 80% amonijum-sulfat, umrežavajući reagens 1% glutaraldehid i goveđi serum albumin koncentracije 5 mg ml-1. Dobijeni umreženi agregat peroksidaze iz rena pokazao je veliki afinitet prema model antrahinonskoj boji, C. I. AV 109. Pod optimalnim uslovima: pH 4, koncentracja boje 40 mg-1, koncentracija H2O2 i 0,1 U enzimske aktivnosti oksidovano je 88,4% ispitivane boje. Mogućnost primene imobilisanog enzima kroz pet i osam uzastopnih ciklusa oksidacije boje i pirogalola (zadržana aktivnost 80%) pokazuje da je imobilisani enzim efikasan i ekološki prihvatljiv biokatalizator koji se može koristiti u oksidaciji aromatičnih jedinjenja iz otpadnih voda. Ovaj rad predstavlja nastavak istraživanja vezanog za umrežavanje peroksidaze iz svežeg ekstrakta rena, koja se takođe pokazala kao imobilisani biokatalizator sa velikim potencijalom primene u tretmanu obojenih otpadnih voda.
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- 2016
38. Krompirova džibra i melasa šećerne repe kao supstrat za proizvodnju mlečne kiseline i probiotske biomase
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Mladenović, Dragana, Pejin, Jelena, Kocić-Tanackov, Sunčica, Stefanović, Andrea, Đukić-Vuković, Aleksandra, and Mojović, Ljiljana
- Subjects
animal feed ,molasses ,probiotics ,krompirova džibra ,probiotici ,mlečna kiselina ,fungi ,lactic acid ,food and beverages ,hrana za životinje ,melasa ,potato stillage - Abstract
Distillery stillage is abundant industrial waste with a great potential for utilization as a substrate in production of valuable bio-based products. Processing of distillery stillage on cost effective way can significantly decrease the price of bioethanol as alternative fuel and provide a considerable benefit to the environment. In this paper, combined potato stillage and sugar beet molasses substrate is evaluated for integrated lactic acid and probiotic biomass production by Lactobacillus rhamnosus ATCC 7469. Waste substrate based on potato stillage and sugar beet molasses enabled lactic acid and biomass production with maximal volumetric lactic acid productivity of 1.11 g L-1 h-1 and maximal number of viable L. rhamnosus ATCC 7469 cells of 1.1×109 CFU mL-1. Residue after removal of lactic acid could be recommended as probiotics and betaine-enriched animal feed. Destilerijska džibra je lako dostupan industrijski otpad koji nastaje u proizvodnji bioetanola, a zbog svog kompleksnog sastava može biti potencijalno dobar supstrat u mnogim biotehnološkim procesima. Imajući u vidu potrebu za povećanjem postojećih i izgradnjom novih kapaciteta za proizvodnju bioetanola, iskorišćavanje otpadne džibre može biti značajno sa aspekta povećanja konkurentnosti bioetanola kao alternativnog goriva, a može imati i pozitivan uticaj na životnu sredinu. U radu je ispitivana mogućnost iskorišćavanja krompirove džibre i melase šećerne repe kao supstrata za paralelnu proizvodnju mlečne kiseline i bakterijske biomase, pomoću probiotskog soja Lactobacillus rhamnosus ATCC 7469. U šaržnoj fermentaciji na ovom kombinovanom supstratu bez dodatnog obogaćivanja vitaminima, mineralnim materijama ili izvorima azota je postignuta maksimalna produktivnost od 1,11 g L-1 h-1, maksimalan broj vijabilnih ćelija od 1,1×109 CFU mL-1 i koncentracija mlečne kiseline od 18,08 g L-1. Krompirova džibra se može koristiti kao supstrat za rast probiotske biomase i može biti adekvatna zamena za skupe, najčešće korišćene organske izvore azota, kao što su kvaščev ekstrakt ili pepton. Usled nemogućnosti L. rhamnosus ATCC 7469 da podjednako dobro metaboliše sve šećere u melasi šećerne repe za efikasniju proizvodnju mlečne kiseline treba razmotriti druge izvore ugljenika ili izvršiti selekciju Lactobacillus sp. koji efikasno fermentiše saharozu iz melase. Zbog značajnog rasta bakterijske biomase tokom procesa, fermentisani medijum koji zaostaje nakon ekstrakcije mlečne kiseline predstavlja vredan sporedni proizvod fermentacije bogat probiotskom biomasom i betainom koji se može koristiti kao visoko kvalitetna hrana za životinje.
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- 2016
39. Ultrasound Pretreatment as an Useful Tool to Enhance Egg White Protein Hydrolysis: Kinetics, Reaction Model, and Thermodinamics
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Jovanović, Jelena, Stefanović, Andrea, Šekuljica, Nataša, Jakovetić Tanasković, Sonja, Dojčinović, Marina, Bugarski, Branko, and Knežević-Jugović, Zorica
- Subjects
particle characteristics ,enzymatic hydrolysis ,kinetic model ,ultrasound pretreatment ,EWPs - Abstract
The impact of ultrasound waves generated by probe-type sonicator and ultrasound cleaning bath on egg white protein susceptibility to hydrolysis by alcalase compared to both thermal pretreatment and conventional enzymatic hydrolysis was quantitatively investigated. A series of hydrolytic reactions was carried out in a stirred tank reactor at different substrate concentrations, enzyme concentrations, and temperatures using untreated, and pretreated egg white proteins (EWPs). The kinetic model based on substrate inhibition and second-order enzyme deactivation successfully predicts the experimental behavior providing an effective tool for comparison and optimization. The ultrasound pretreatments appear to greatly improve the enzymatic hydrolysis of EWPs under different conditions when compare to other methods. The apparent reaction rate constants for proteolysis (k(2)) are 0.009, 0.011, 0.053, and 0.045 min(-1) for untreated EWPs, and those pretreated with heat, probe-type sonicator, and ultrasound cleaning bath technologies, respectively. The ultrasound pretreatment also decreases hydrolysis activation (E-a) and enzyme deactivation (E-d) energy, enthalpy (Delta H), and entropy (Delta S) of activation and for the probe-type sonication this decrease is 61.7%, 61.6%, 63.6%, and 32.2%, respectively, but ultrasound has little change in Gibbs free energy value in the temperature range of 318 to 338 K. The content of sulfhydryl groups and zeta potential show a significant increase (P lt 0.05) for both applied ultrasound pretreatments and the reduction of particle size distribution are achieved, providing some evidence that the ultrasound causes EWP structural changes affecting the proteolysis rate.
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- 2016
40. The synergistic effect of heat treatment on alcalase-assisted hydrolysis of wheat gluten proteins: Functional and antioxidant properties
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Elmalimadi, Mohamed B., primary, Stefanović, Andrea B., additional, Šekuljica, Nataša Ž., additional, Žuža, Milena G., additional, Luković, Nevena D., additional, Jovanović, Jelena R., additional, and Knežević-Jugović, Zorica D., additional
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- 2017
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41. Аntioxidant activity of peptide fractions obtained by membrane ultrafiltration of egg white protein enzymatic hydrolysates
- Author
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Knežević-Jugović, Zorica, Jovanović, Jelena, Stefanović, Andrea, Žuža, Milena, Šekuljica, Nataša, Manojlović, Verica, and Bugarski, Branko
- Subjects
Membrane ultrafiltration ,Ultrasound pretreatment ,Egg white proteins ,Antioxidant peptides - Abstract
The objective of this research was a production of egg white protein hydrolysates with improved antioxidant properties. For this purpose, a thermal and ultrasound pretreated egg white proteins were intensively hydrolysed with a commercial food-grade bacterial protease Alcalase. Thus obtained hydrolysates were further separated by sequential ultrafiltration into four peptide fraction viz. Fraction I (> 30kDa), II (10 - 30 kDa), III (1 - 10 kDa) and IV (< 1kDa) which were investigated in terms of their antioxidant activity. The antioxidant activity of hydrolysates and peptide fractions were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging assays and measuring ferric reducing antioxidant power assay. Scavenging of 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) by Fraction III, prepared with ultrasound pretreatment (35 kHz - 30 min) was found to be significantly higher than other fractions (21.17 ± 2.01 % and 80.72 ± 1.32 %, respectively), while ferric reducing antioxidant power assay has proven to be the best for thermal pretreatment. The results show that the fractionated hydrolysates were superior to the original hydrolysate in the antioxidative activity tested and can be concluded that by combining ultrasound pretreatment hydrolysates with improved functional and antioxidant properties can be produced enhancing utilization of egg white in food products.
- Published
- 2015
42. Peptides with improved antimicrobial activity screened by membrane ultrafiltration from egg white protein hydrolysates
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Jovanović, Jelena, Stefanović, Andrea, Grbavčić, Sanja, Šekuljica, Nataša, Elmalimadi, Mohamed B., Bugarski, Branko, and Knežević-Jugović, Zorica
- Subjects
Membrane ultrafiltration ,Hydrolysis ,Antimicrobial derived egg white peptides ,Radial diffusion assay ,Alcalase - Abstract
This contribution was aimed at the fractionation and identification of peptides with improved antimicrobial activity from egg white protein hydrolysates, obtained by membrane ultrafiltration. For this purpose, the thermal treated egg white proteins were intensively hydrolysed with a commercial food-grade bacterial endopeptidase from Bacillus licheniformis, namely Alcalase. Thus, obtained hydrolysates were further separated by sequential ultrafiltration into four peptide fractions viz. fraction I (> 30kDa), II (10 - 30 kDa), III (1 - 10 kDa) and IV (< 1kDa) which were investigated in terms of their antimicrobial activity. The antimicrobial activity was tested against Gram-positive bacteria (Staphylococcus aureus ATCC 25923), Gram-negative bacteria (Escherichia coli ATCC 25922) and against yeast Candida albicans (ATCC 24433) by fractions' susceptibility of agar diffusion. Our results showed that these peptide fractions have an intense inhibitory activity on Gram-positive bacteria, poor on Gram-negative bacteria and none inhibitory activity on growth of C. albicans. The results showed interesting antimicrobial potentials versus the tested microorganisms, especially fractions with peptides molecular weight of 10-30 kDa and 1-10 kDa. It can be concluded, that the controlled enzymatic hydrolysis of egg white proteins and their subsequent membrane ultrafiltration is considered to be a suitable way for production of biocative peptides with exhibit antimicrobial efficiency.
- Published
- 2015
43. KAOLIN AS A SUPPORT FOR THE IMMOBILIZATION OF HORSERADISH PEROXIDASE: APPLICATION IN ANTHRAQUINONIC DYES DECOLORIZATION FROM WASTEWATER
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Šekuljica, Nataša, Prlainović, Nevena, Mijalković, Jelena, Stefanović, Andrea, Mijin, Dušan, and Knežević-Jugović, Zorica
- Subjects
dye ,horseradish peroxidase ,immobilization ,wastewater - Abstract
The world is facing with global water crisis because around 20 % of untreated or partially treated wastewater is discharged directly into the environment. The main objective of this paper was to develop an eco-friendly, sustainable biocatalyst for the decolorization of wastewater from different industries colored with anthraquinonic dyes. Anthraquinonic dyes have fused aromatic rings, which makes them extremely stabile against photolytic degradation as well as microbial attack. They are synthesized from antracene, toluene, benzidine so their brakedown products are toxic, muthagenic, carcinogenic. Natural clay, kaolin was used as a support for the immobilization of horseradish peroxidase. Prior to immobilization kaolin was activated with different concentrations of glutaraldehyde (0.1-1%). Next, concentration of the enzyme was varied in the range 0.5-5 mg cm-3 , and the maximum loading of 2.19 mg g-1 was obtained. The efficiency of the attained biocatalyst was examined in the reaction with model dye C. I. Acid Violet 109. Under defined conditions more than 90 % of the dye was removed within 40 min. Immobilized HRP approved as a much more stable in a wider pH range than free HRP. Besides, inhibitory influence of peroxide and dye after immobilization was reduced significantly. Furthermore, immobilized HRP exhibited reasonable reusability during the decolorization of tested anthraquinonic dye.
- Published
- 2015
44. Obezbojavanje antrahinonskih boja peroksidazom izolovanom iz svežeg ekstrakta rena
- Author
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Šekuljica, Nataša, Prlainović, Nevena, Stefanović, Andrea, Jovanović, Jelena, Mijin, Dušan, and Knežević-Jugović, Zorica
- Abstract
Peroksidaza iz rena se pokazala kao izuzetan biokatalizator za oksidaciju brojnih aromatičnih jedinjenja uključujući i antrahinonske boje. Poslednjih godina reakcije oksidacije antrahinonskih boja katalizovane peroksidazom iz rena sve više dobijaju na značaju zbog blagih reakcionih uslova, velike efikasnosti, malih utrošaka energije i ekološki prihvatljivih sporednih proizvoda. U cilju zaštite zdravlja čoveka i životne sredine, pre ispuštanja otpadnih voda u prirodne vodotokove neophodan je njihov pravilan tretman. U cilju ispitivanja obezbojavanja, kao model su izabrane dve antrahinonske boje: C.I. Acid Violet 109 (AV 109) i C.I. Acid Blue 225 (AB 225). U reakciji razgradnje izabranih antrahinonskih boja korišćena je peroksidaza iz svežeg ekstrakta rena bez daljeg prečišćavanja. U reakcijama katalizovanim sa 0,1 IU enzimske aktivnosti uklonjeno je 89 % AV 109 boje nakon 30 minuta (pH 4,0, koncentracija vodonik-peroksida 0,1 mM, koncentracija boje 30 mg dm-3) i 75 % AB 225 boje (pH 5,0, koncentracija vodonik-peroksida 0,2 mM, koncentracija boje 30 mg dm-3) nakon 40 minuta.
- Published
- 2015
45. Hydrolysis of egg white and wheat proteins with protease from bacillus licheniformis: fractionation and identification of bioactive peptides
- Author
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Knežević-Jugović, Zorica, Jovanović, Jelena, Stefanović, Andrea, Grbavčić, Sanja, Šekuljica, Nataša, Elmalimadi, Mohamed B., and Bugarski, Branko
- Subjects
Enzymatic hydrolysis ,Membrane ultrafiltration ,Egg white proteins ,Antioxidant peptides ,Gluten - Abstract
Wheat gluten is a relatively inexpensive industrial byproduct from wheat starch processing, and in Europe also from manufacturing of bioethanol fuel. Egg producers are also faced with problems of excess of egg white because mayonnaise industry and bakery industry use relatively high egg yolk amounts and egg white is the remainder. Of high importance is the production of new value-added products based on gluten and/or egg white proteins with improved properties and specialized functionality to be used in food and biobased consumer products. The objective of this research was a production of both wheat gluten and egg white protein hydrolysates with improved antioxidant properties. For this purpose, both substrates were pretreated by thermal treatment and then intensively hydrolysed with a commercial food-grade bacterial protease, Alcalase. Thus, the obtained hydrolysates were further separated by sequential ultrafiltration into four peptide fraction viz. Fraction I (> 30kDa), II (10 - 30 kDa), III (1 - 10 kDa) and IV (< 1kDa) which were investigated in terms of their antioxidant activity. The antioxidant activity of hydrolysates and peptide fractions were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) radical scavenging assays and measuring ferric reducing antioxidant power assay. Scavenging of 2,2′- diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) by Fraction III, prepared with gluten protein was found to be significantly higher than other gluten or egg white fractions. The results show that the fractionated hydrolysates were superior to the original hydrolysate in the antioxidative activity tested in all cases and can be concluded that by combining thermal pretreatment and controlled enzymatic hydrolysis, the hydrolysates with improved antioxidant properties can be produced enhancing utilization of egg white and gluten in food products.
- Published
- 2015
46. Immobilization of horseradish peroxidase onto kaolin
- Author
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Šekuljica, Nataša, Prlainović, Nevena, Jovanović, Jelena, Stefanović, Andrea, Đokić, Veljko, Mijin, Dušan, Knežević-Jugović, Zorica, Šekuljica, Nataša, Prlainović, Nevena, Jovanović, Jelena, Stefanović, Andrea, Đokić, Veljko, Mijin, Dušan, and Knežević-Jugović, Zorica
- Abstract
Kaolin showed as a very perspective carrier for the enzyme immobilization and it was used for the adsorption of horseradish peroxidase (HRP). The effects of the enzyme concentration and pH on the immobilization efficiency were studied in the reaction with pyrogallol and anthraquinone dye C.I. Acid Violet 109 (AV 109). In addition, Fourier transform infrared spectroscopy, scanning electron microscopy and analysis by Brunauer-EmmettTeller were performed for kaolin, thermally activated kaolin and the immobilized enzyme. It has been shown that 0.1 IU of HRP-kaolin decolorized 87 % of dye solution, under the optimal conditions (pH 5.0, temperature 24 degrees C, dye concentration 40 mg/L and 0.2 mM of H2O2) within 40 min. The immobilized HRP decolorization follows the Ping Pong Bi-Bi mechanism with dead-end inhibition by the dye. The biocatalyst retained 35 +/- 0.9 % of the initial activity after seven cycles of reuse in the decolorization reaction of AV 109 under optimal conditions in a batch reactor. The obtained kinetic parameters and reusability study confirmed improvement in performances of k-HRP compared to free, indicating that k-HRP has a great potential for environmental purposes.
- Published
- 2016
47. Immobilization of horseradish peroxidase onto kaolin by glutaraldehyde method and its application in decolorization of anthraquinone dye
- Author
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Šekuljica, Nataša, Prlainović, Nevena, Jovanović, Jelena, Stefanović, Andrea, Grbavčić, Sanja, Mijin, Dušan, Knežević-Jugović, Zorica, Šekuljica, Nataša, Prlainović, Nevena, Jovanović, Jelena, Stefanović, Andrea, Grbavčić, Sanja, Mijin, Dušan, and Knežević-Jugović, Zorica
- Abstract
The problem of environmental pollution becomes more worrisome day by day, primarily due to the large amounts of wastewater contaminated with various harmful organic compounds, discharged untreated or partially clean into the environment. Feasibility of use of horseradish peroxidase (Amoracia rusticana) in the synthetic dyes decolorization was approved by many researchers. Among a number of supports used for the immobilization, it was found that natural clay, kaolin, has excellent features which are a precondition for obtaining biocatalysts with the excellent performances. For this reason, a horseradish peroxidase was immobilized onto kaolin using glutaraldehyde as a cross-linking agent. Obtained biocatalyst was applied in the decolorization of anthraquinone dye C.I. acid violet 109. Under determined optimal conditions (pH 4.0, hydrogen peroxide concentration 0.6 mM, dye concentration 30 mg L-1, temperature 24 degrees C) around 76% of dye decolorization was achieved. Reusability study showed that resulting biocatalyst was possible to apply four times in the desired reaction with relatively high decolorization percentage.
- Published
- 2016
48. Improvement of antioxidant properties of egg white protein enzymatic hydrolysates by membrane ultrafiltration
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Jovanović, Jelena, Stefanović, Andrea, Žuža, Milena, Jakovetić, Sonja, Šekuljica, Nataša, Bugarski, Branko, Knežević-Jugović, Zorica, Jovanović, Jelena, Stefanović, Andrea, Žuža, Milena, Jakovetić, Sonja, Šekuljica, Nataša, Bugarski, Branko, and Knežević-Jugović, Zorica
- Abstract
The production of bioactive peptides from egg white proteins (EWPs) and their separation are emerging areas with many new applications. The objective of this study was to compare antioxidant activity of three distinct EWP hydrolysates and their peptide fractions prepared by membrane ultrafiltration using membranes with 30, 10 and 1 kDa molecular weight cut-off. The hydrolysates were obtained by thermal and ultrasound pretreated EWPs hydrolyzed with a bacterial protease, Alcalase. It appeared that the pretreatment significantly affected peptide profiles and antioxidant activity of the hydrolysates measured by ABTS, DPPH and FRAP methods. The hydrolysate prepared using alcalase and ultrasound pretreatment at 40 kHz - 15 min has shown to be the most effective in scavenging both DPPH and ABTS radicals (28.10 +/- 1.38 and 79.44 +/- 2.31%, respectively). It has been noticed that this hydrolysate had a nutritionally more adequate peptide profile than the other hydrolysates with a much lower amount of peptides lt 1 kDa (11.19 +/- 0.53%) and the greatest content of the peptide fraction in the molecular weight (MW) range of 1-10 kDa (28.80 +/- 0.07%). This peptide fraction has shown the highest DPPH and ABTS antioxidant activity compared to all other fractions having a potential to be used as a functional food ingredient.
- Published
- 2016
49. The oxidation of anthraquinone dye using HRP immobilized as a cross-linked enzyme aggregates
- Author
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Šekuljica, Nataša, Prlainović, Nevena, Stefanović, Andrea, Jovanović, Jelena, Jakovetić, Sonja, Knežević-Jugović, Zorica, Mijin, Dušan, Šekuljica, Nataša, Prlainović, Nevena, Stefanović, Andrea, Jovanović, Jelena, Jakovetić, Sonja, Knežević-Jugović, Zorica, and Mijin, Dušan
- Abstract
Finding a sustainable and ecofriendly methods for recalcitrant synthetic dyes removal is a researchers major challenge. A carrier-free technique for commercial HRP immobilization is a focus of the present study. The immobilized biocatalyst, HRP-CLEAs with 580 U g-1 of the activity was obtained under the following immobilization conditions: precipitation reagent 80% ammonium sulphate, cross-linking reagent 1% of glutaraldehyde and protein-fedder, bovine serum albumin (BSA) concentration 5 mg ml-1. The obtained HRP-CLEAs showed great affinity towards model anthraquinone dye, C. I. Acid Violet 109. 88.4% of the dye was oxidized under the reaction conditions: pH 4, dye concentration 40 mg l-1, H2O2 concentration 1 mM and 0.1 U of HRP-CLEAs. The possibility of the immobilized biocatalyst application in five and eight oxidation cycles of the dye and pyrogallol (retained activity 80%), respectively, indicates that HRP-CLEAs is an efficient and environmentally friendly biocatalyst with great potential in aromatic compounds removal from wastewater. This paper is a continuation of our earlier research related to HRP from horseradish extract immobilization in the form of CLEAs and the application in the wastewater colored with a synthetic anthraquinone dye treatment., Pronalazak održivih i ekološki prihvatljivih metoda za uklanjanje sintetičkih boja je jedan od vodećih izazova za istraživače. U ovom radu akcenat je na metodi imobilizacije bez primene nosača. Imobilisani preparat peroksidaze iz rena, aktivnosti 580 U g-1 dobijen je pod sledećim uslovima imobilizacije: taložni reagens 80% amonijum-sulfat, umrežavajući reagens 1% glutaraldehid i goveđi serum albumin koncentracije 5 mg ml-1. Dobijeni umreženi agregat peroksidaze iz rena pokazao je veliki afinitet prema model antrahinonskoj boji, C. I. AV 109. Pod optimalnim uslovima: pH 4, koncentracja boje 40 mg-1, koncentracija H2O2 i 0,1 U enzimske aktivnosti oksidovano je 88,4% ispitivane boje. Mogućnost primene imobilisanog enzima kroz pet i osam uzastopnih ciklusa oksidacije boje i pirogalola (zadržana aktivnost 80%) pokazuje da je imobilisani enzim efikasan i ekološki prihvatljiv biokatalizator koji se može koristiti u oksidaciji aromatičnih jedinjenja iz otpadnih voda. Ovaj rad predstavlja nastavak istraživanja vezanog za umrežavanje peroksidaze iz svežeg ekstrakta rena, koja se takođe pokazala kao imobilisani biokatalizator sa velikim potencijalom primene u tretmanu obojenih otpadnih voda.
- Published
- 2016
50. Potato stillage and sugar beet molasses as a substrate for production of lactic acid and probiotic biomass
- Author
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Mladenović, Dragana, Pejin, Jelena, Kocić-Tanackov, Sunčica, Stefanović, Andrea, Djukić-Vuković, Aleksandra, Mojović, Ljiljana, Mladenović, Dragana, Pejin, Jelena, Kocić-Tanackov, Sunčica, Stefanović, Andrea, Djukić-Vuković, Aleksandra, and Mojović, Ljiljana
- Abstract
Distillery stillage is abundant industrial waste with a great potential for utilization as a substrate in production of valuable bio-based products. Processing of distillery stillage on cost effective way can significantly decrease the price of bioethanol as alternative fuel and provide a considerable benefit to the environment. In this paper, combined potato stillage and sugar beet molasses substrate is evaluated for integrated lactic acid and probiotic biomass production by Lactobacillus rhamnosus ATCC 7469. Waste substrate based on potato stillage and sugar beet molasses enabled lactic acid and biomass production with maximal volumetric lactic acid productivity of 1.11 g L-1 h-1 and maximal number of viable L. rhamnosus ATCC 7469 cells of 1.1×109 CFU mL-1. Residue after removal of lactic acid could be recommended as probiotics and betaine-enriched animal feed., Destilerijska džibra je lako dostupan industrijski otpad koji nastaje u proizvodnji bioetanola, a zbog svog kompleksnog sastava može biti potencijalno dobar supstrat u mnogim biotehnološkim procesima. Imajući u vidu potrebu za povećanjem postojećih i izgradnjom novih kapaciteta za proizvodnju bioetanola, iskorišćavanje otpadne džibre može biti značajno sa aspekta povećanja konkurentnosti bioetanola kao alternativnog goriva, a može imati i pozitivan uticaj na životnu sredinu. U radu je ispitivana mogućnost iskorišćavanja krompirove džibre i melase šećerne repe kao supstrata za paralelnu proizvodnju mlečne kiseline i bakterijske biomase, pomoću probiotskog soja Lactobacillus rhamnosus ATCC 7469. U šaržnoj fermentaciji na ovom kombinovanom supstratu bez dodatnog obogaćivanja vitaminima, mineralnim materijama ili izvorima azota je postignuta maksimalna produktivnost od 1,11 g L-1 h-1, maksimalan broj vijabilnih ćelija od 1,1×109 CFU mL-1 i koncentracija mlečne kiseline od 18,08 g L-1. Krompirova džibra se može koristiti kao supstrat za rast probiotske biomase i može biti adekvatna zamena za skupe, najčešće korišćene organske izvore azota, kao što su kvaščev ekstrakt ili pepton. Usled nemogućnosti L. rhamnosus ATCC 7469 da podjednako dobro metaboliše sve šećere u melasi šećerne repe za efikasniju proizvodnju mlečne kiseline treba razmotriti druge izvore ugljenika ili izvršiti selekciju Lactobacillus sp. koji efikasno fermentiše saharozu iz melase. Zbog značajnog rasta bakterijske biomase tokom procesa, fermentisani medijum koji zaostaje nakon ekstrakcije mlečne kiseline predstavlja vredan sporedni proizvod fermentacije bogat probiotskom biomasom i betainom koji se može koristiti kao visoko kvalitetna hrana za životinje.
- Published
- 2016
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