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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.

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]

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

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]

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. [ABSTRACT FROM AUTHOR]

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 the extraction enabled a substantial increase in the extracted phenolics and that the method could be successfully applied with other agro-industrial by-products providing extracts with antioxidative potential. [ABSTRACT FROM AUTHOR]

In recent years, there has been an unprecedented demand 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 endoprotease from Bacillus licheniformis on the antioxidant 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 radical-scavenging and metal-chelating assays. The ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic 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 strongly chelating prooxidant ferrous metal ions (> 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 untreated SPC in the analyzed bioactivity and techno-functionality and can be concluded that obtained SPC hydrolysates may be used as new value-added functional ingredients. [ABSTRACT FROM AUTHOR]

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 min. 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. [ABSTRACT FROM AUTHOR]

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 30 min at 75 °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 applications This 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 with improved properties can be produced enhancing utilization of WGP in food products. [ABSTRACT FROM AUTHOR]

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 ( k2) 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 ( Ea) and enzyme deactivation ( Ed) energy, enthalpy (Δ H), and entropy (Δ 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 ζ potential show a significant increase ( P < 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. [ABSTRACT FROM AUTHOR]

Two anthraquinonic dyes, C.I. Acid Blue 225 and C.I. Acid Violet 109, were used as models to explore the feasibility of using the horseradish peroxidase enzyme (HRP) in the practical decolorization of anthraquinonic dyes in wastewater. The influence of process parameters such as enzyme concentration, hydrogen peroxide concentration, temperature, dye concentration, and pH was examined. The pH and temperature activity profiles were similar for decolorization of both dyes. Under the optimal conditions, 94.7% of C.I. Acid Violet 109 from aqueous solution was decolorized (treatment time 15 min, enzyme concentration 0.15 IU/mL, hydrogen peroxide concentration 0.4 mM, dye concentration 30 mg/L, pH 4, and temperature 24°C) and 89.36% of C.I. Acid Blue 225 (32 min, enzyme concentration 0.15 IU/mL, hydrogen peroxide concentration 0.04 mM, dye concentration 30 mg/L, pH 5, and temperature 24°C). The mechanism of both reactions has been proven to follow the two substrate ping-pong mechanism with substrate inhibition, revealing the formation of a nonproductive or dead-end complex between dye and HRP or between H2O2 and the oxidized form of the enzyme. Both chemical oxygen demand and total organic carbon values showed that there was a reduction in toxicity after the enzymatic treatment. This study verifies the viability of use of horseradish peroxidase for the wastewaters treatment of similar anthraquinonic dyes. [ABSTRACT FROM AUTHOR]