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Predmet naučnog istraživanja doktorske disertacije je razvoj i optimizacija postupka ekstrakcije bioaktivnih jedinjenja, polifenolnih kiselina i proteina iz semena žute soje primenom tehnologije ultrazvuka visoke frekvencije i mikrotalasnog zračenja..., The scope of this academic doctoral research is the development and optimization of the process of extraction of bioactive compounds, polyphenolic acids and proteins from yellow soybean seed using high-intensity ultrasound technology and microwave technology...

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.

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.

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 presen

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 presen

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.

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.

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.

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.

Industrial residues are resources that generate regional energy security but they have not been sufficiently valued. In southern Colombia, the sugar cane sector produces approximately 9'000 000 T/year of residues, mostly represented by tops and leaves. Delignification is a critical step in the process of obtaining ethanol from these residues. The removal of lignin using extracellular enzyme extracts and mediators has not been widely studied. Therefore, a methodology was developed to extract, a cocktail of enzymes consisting of laccase, manganese peroxidase (MnP) and lignoperoxidase (LiP) from Pleurotus ostreatus, which was cultivated by solid substrate fermentation. The extracts with two mediators: 1) ABTS: 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic-acid and 2) vanillin, were tested on two different types of residues: untreated residues and pretreated residues with ultrasound. It was found that the crude enzyme extract contained laccase (0.432 U/mL), LiP (0.116 U/mL) and MnP (0.025 U/mL) activity. Additionally, the results confirmed that this extract was capable of removing 52.7% of lignin from ultrasound pretreated sugar cane residues and ABTS as the laccase mediator. It is important to highlight that the results obtained were very promising mainly if a more concentrated extracellular extract can be used., Os resíduos industriais são recursos que geram uma segurança energética regional, mas eles não são suficientemente valorizados. No sul da Colômbia, o setor da cana de açúcar produz aproximadamente 9'000 000 T/ano de resíduos, principalmente representados por folhas e miolos. Destes resíduos podemos obter etanol e uma das etapas mais críticas é a deslignificação. Neste processo, a remoção de lignina com o uso de extratos de enzima extracelular e mediadores, ainda não foi amplamente estudada. Consequentemente, foi desenvolvida uma metodologia para a extração do fungo Pleurotus ostreatus, o qual foi cultivado por fermentação em substrato sólido, um coquetel de enzimas composto por lacase, manganês peroxidase (MnP) e lignoperoxidase (LiP). Estes extratos enzimáticos foram testados com o uso dos mediadores: 1) ABTS: 2,2'-azino-bis-3-etilbenzotiazoline-6-ácido sulfônico e 2) vanilina, sobre dois diferentes tipos de resíduos: não tratados e pré-tratados com ultrassom. Como resultado verificou-se que o extrato cru de enzima esteve composto por atividade lacase (0.432 U/mL), LiP (0.116 U/mL) e MnP (0.025 U/mL). Adicionalmente, os resultados confirmaram que esse extrato cru junto com o ABTS como mediador de lacase foi capaz de remover 52.7% da lignina dos resíduos de cana de açúcar pré-tratados com ultrassom. Também é importante salientar que estes resultados foram muito promissórios, designadamente, se é possível utilizar um extrato extracelular mais concentrado., Los residuos industriales son recursos que generan una seguridad energética regional, pero ellos no han sido suficientemente valorizados. En el sur de Colombia, el sector de la caña de azúcar produce aproximadamente 9'000000 T/año de residuos, principalmente representados por hojas y cogollos. De estos residuos es posible obtener etanol y una de las etapas más críticas es su deslignificación. En este proceso, la remoción de lignina con el uso de extractos de enzima extracelular y mediadores, todavía no ha sido ampliamente estudiada. Por consiguiente, se desarrolló una metodología para extraer del hongo Pleurotus ostreatus, el cual fue cultivado por fermentación en substrato sólido, un coctel de enzimas compuesto por lacasa, manganeso peroxidasa (MnP) y lignoperoxidasa (LiP). Estos extractos enzimáticos fueron probados con el uso de dos mediadores: 1) ABTS: 2,2'-azino-bis-3-etilbenzotiazolina-6-ácido sulfonico y 2) vainillina, sobre dos diferentes tipos de residuos: no tratados y pretratados con ultrasonido. Como resultado se encontró que el extracto crudo de enzima estuvo compuesto por actividad lacasa (0.432 U/mL), LiP (0.116 U/mL) y MnP (0.025 U/mL). Adicionalmente, los resultados confirmaron que este extracto crudo en asocio con ABTS como mediador de lacasa, fue capaz de remover el 52.7% de la lignina de los residuos de caña de azúcar pretratados con ultrasonido. También es importante resaltar que estos resultados fueron muy promisorios, sobre todo si se puede usar un extracto extracelular más concentrado.

Industrial residues are resources that generate regional energy security but they have not been sufficiently valued. In southern Colombia, the sugar cane sector produces approximately 9'000 000 T/year of residues, mostly represented by tops and leaves. Delignification is a critical step in the process of obtaining ethanol from these residues. The removal of lignin using extracellular enzyme extracts and mediators has not been widely studied. Therefore, a methodology was developed to extract, a cocktail of enzymes consisting of laccase, manganese peroxidase (MnP) and lignoperoxidase (LiP) from Pleurotus ostreatus, which was cultivated by solid substrate fermentation. The extracts with two mediators: 1) ABTS: 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic-acid and 2) vanillin, were tested on two different types of residues: untreated residues and pretreated residues with ultrasound. It was found that the crude enzyme extract contained laccase (0.432 U/mL), LiP (0.116 U/mL) and MnP (0.025 U/mL) activity. Additionally, the results confirmed that this extract was capable of removing 52.7% of lignin from ultrasound pretreated sugar cane residues and ABTS as the laccase mediator. It is important to highlight that the results obtained were very promising mainly if a more concentrated extracellular extract can be used., Os resíduos industriais são recursos que geram uma segurança energética regional, mas eles não são suficientemente valorizados. No sul da Colômbia, o setor da cana de açúcar produz aproximadamente 9'000 000 T/ano de resíduos, principalmente representados por folhas e miolos. Destes resíduos podemos obter etanol e uma das etapas mais críticas é a deslignificação. Neste processo, a remoção de lignina com o uso de extratos de enzima extracelular e mediadores, ainda não foi amplamente estudada. Consequentemente, foi desenvolvida uma metodologia para a extração do fungo Pleurotus ostreatus, o qual foi cultivado por fermentação em substrato sólido, um coquetel de enzimas composto por lacase, manganês peroxidase (MnP) e lignoperoxidase (LiP). Estes extratos enzimáticos foram testados com o uso dos mediadores: 1) ABTS: 2,2'-azino-bis-3-etilbenzotiazoline-6-ácido sulfônico e 2) vanilina, sobre dois diferentes tipos de resíduos: não tratados e pré-tratados com ultrassom. Como resultado verificou-se que o extrato cru de enzima esteve composto por atividade lacase (0.432 U/mL), LiP (0.116 U/mL) e MnP (0.025 U/mL). Adicionalmente, os resultados confirmaram que esse extrato cru junto com o ABTS como mediador de lacase foi capaz de remover 52.7% da lignina dos resíduos de cana de açúcar pré-tratados com ultrassom. Também é importante salientar que estes resultados foram muito promissórios, designadamente, se é possível utilizar um extrato extracelular mais concentrado., Los residuos industriales son recursos que generan una seguridad energética regional, pero ellos no han sido suficientemente valorizados. En el sur de Colombia, el sector de la caña de azúcar produce aproximadamente 9'000000 T/año de residuos, principalmente representados por hojas y cogollos. De estos residuos es posible obtener etanol y una de las etapas más críticas es su deslignificación. En este proceso, la remoción de lignina con el uso de extractos de enzima extracelular y mediadores, todavía no ha sido ampliamente estudiada. Por consiguiente, se desarrolló una metodología para extraer del hongo Pleurotus ostreatus, el cual fue cultivado por fermentación en substrato sólido, un coctel de enzimas compuesto por lacasa, manganeso peroxidasa (MnP) y lignoperoxidasa (LiP). Estos extractos enzimáticos fueron probados con el uso de dos mediadores: 1) ABTS: 2,2'-azino-bis-3-etilbenzotiazolina-6-ácido sulfonico y 2) vainillina, sobre dos diferentes tipos de residuos: no tratados y pretratados con ultrasonido. Como resultado se encontró que el extracto crudo de enzima estuvo compuesto por actividad lacasa (0.432 U/mL), LiP (0.116 U/mL) y MnP (0.025 U/mL). Adicionalmente, los resultados confirmaron que este extracto crudo en asocio con ABTS como mediador de lacasa, fue capaz de remover el 52.7% de la lignina de los residuos de caña de azúcar pretratados con ultrasonido. También es importante resaltar que estos resultados fueron muy promisorios, sobre todo si se puede usar un extracto extracelular más concentrado.

The objective of this study was to investigate the effects of different ultrasound pretreatment on enzymatic hydrolysis of egg white proteins (EWPs) by Alcalase as well as evaluating some functional and antioxidant properties of hydrolysates obtained by various proteases treatment and ultrasound technology. The effects of chosen ultrasound pretreatment parameters including frequency of ultrasonic waves (35 and 40 kHz), temperature (25 and 55 A degrees C), time of pretreatment (15-60 min) and pH of egg white solution (7.00-10.00) were examined. It appeared that controlled ultrasound treatment can improved the hydrolysis process compared with untreated samples, but optimization of the power and length of sonication was important. The optimal ultrasound pretreatment at calorimetric power of 21.3 W and frequency of 40 kHz for 15 min at 25 A degrees C and with naturally basic egg white (pH 9.25) resulted in increased initial rate and equilibrium degree of Alcalase hydrolysis by about 139.8 and 13.86 % compared with the control, respectively. EWP hydrolysates with a parts per thousand 27.0 % degree of hydrolysis obtained with heat pretreatment and ultrasound pretreatments under optimal conditions were further separated by sequential ultrafiltration into 4 hydrolysate fractions ( lt 1, 1-10, 10-30 and gt 30 kDa) which were investigated for protein content, peptide yield and antioxidant activity. The hydrolysis after heat pretreatment generated more peptides lt 1 kDa (19.04 +/- A 1.02 %) than ultrasound pretreatment did (11.90 +/- A 0.53 %), whereas the proportion of peptides lt 10 kDa were higher in the second case (28.80 +/- A 0.07 vs. 20.46 +/- A 0.39 %). The fraction obtained by the ultrasound pretreatment containing peptides with a molecular weight between 1 and 10 kDa demonstrated the strongest ABTS radical scavenging efficacy among the fractions (97.54 +/- A 0.30) with IC50 value of 4.31 mg/mL. Compared with single-enzyme processes, the two-stage enzymatic processes

The objective of this study was to investigate the effect of ultrasound pretreatment on two-step enzymatic hydrolysis of egg white proteins (EWPs) using commercial food-grade proteases as well as evaluating some functional properties of obtained hydrolysates. Three commercially available proteases used in this work were: alcalase from Bacillus licheniformis, neutrase from Bacillus amyloliquefaciens and flavourzyme from Aspergillus oryzae. Thus obtained hydrolysates were further separated by sequential ultrafiltration into three peptide fraction viz. Fraction I (< 1kDa), II (1 - 10 kDa), III (10 - 30 kDa) 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) radical scavenging assay. Comparing the hydrolytic curves of two-step enzymatic process, the highest equilibrium degree of hydrolysis (DH) was achieved by a combination of alcalase and neutrase. The order of addition of these two proteolytic enzymes didn't lead to significant differences in the initial rate of reaction, but significantly affected the equilibrium DH (32.25 ± 2.08%). The two-step hydrolysis, in which flavourzyme is followed by alcalase, seemed to perform with the same initial rate, but DH was considerably lower (28.23 ± 0.91%). Two-step enzymatic hydrolysis appeared to increase solubility and substantially improved the foam stability while the foam capacity didn't change significantly vs. control. The high yield of peptides soluble at pH 6 and pH 8 were obtained by combination of alcalase and flavourzyme while more voluminous foams were obtained with alcalase and neutrase. The most abundant fraction in terms of antioxidant activity was the Fraction II, which indicates that the combination of alcalase and flavourzyme was efficient at reducing the pretreated into low molecular weight peptides. This study showed that by combining ultrasound pretreatment under controlled co

The objective of this study was to investigate the effects of different ultrasound pretreatment on enzymatic hydrolysis of egg white proteins (EWPs) by Alcalase as well as evaluating some functional and antioxidant properties of hydrolysates obtained by various proteases treatment and ultrasound technology. The effects of chosen ultrasound pretreatment parameters including frequency of ultrasonic waves (35 and 40 kHz), temperature (25 and 55 A degrees C), time of pretreatment (15-60 min) and pH of egg white solution (7.00-10.00) were examined. It appeared that controlled ultrasound treatment can improved the hydrolysis process compared with untreated samples, but optimization of the power and length of sonication was important. The optimal ultrasound pretreatment at calorimetric power of 21.3 W and frequency of 40 kHz for 15 min at 25 A degrees C and with naturally basic egg white (pH 9.25) resulted in increased initial rate and equilibrium degree of Alcalase hydrolysis by about 139.8 and 13.86 % compared with the control, respectively. EWP hydrolysates with a parts per thousand 27.0 % degree of hydrolysis obtained with heat pretreatment and ultrasound pretreatments under optimal conditions were further separated by sequential ultrafiltration into 4 hydrolysate fractions ( lt 1, 1-10, 10-30 and gt 30 kDa) which were investigated for protein content, peptide yield and antioxidant activity. The hydrolysis after heat pretreatment generated more peptides lt 1 kDa (19.04 +/- A 1.02 %) than ultrasound pretreatment did (11.90 +/- A 0.53 %), whereas the proportion of peptides lt 10 kDa were higher in the second case (28.80 +/- A 0.07 vs. 20.46 +/- A 0.39 %). The fraction obtained by the ultrasound pretreatment containing peptides with a molecular weight between 1 and 10 kDa demonstrated the strongest ABTS radical scavenging efficacy among the fractions (97.54 +/- A 0.30) with IC50 value of 4.31 mg/mL. Compared with single-enzyme processes, the two-stage enzymatic processes

The objective of this study was to investigate the effects of different ultrasound pretreatment on enzymatic hydrolysis of egg white proteins (EWPs) by Alcalase as well as evaluating some functional and antioxidant properties of hydrolysates obtained by various proteases treatment and ultrasound technology. The effects of chosen ultrasound pretreatment parameters including frequency of ultrasonic waves (35 and 40 kHz), temperature (25 and 55 A degrees C), time of pretreatment (15-60 min) and pH of egg white solution (7.00-10.00) were examined. It appeared that controlled ultrasound treatment can improved the hydrolysis process compared with untreated samples, but optimization of the power and length of sonication was important. The optimal ultrasound pretreatment at calorimetric power of 21.3 W and frequency of 40 kHz for 15 min at 25 A degrees C and with naturally basic egg white (pH 9.25) resulted in increased initial rate and equilibrium degree of Alcalase hydrolysis by about 139.8 and 13.86 % compared with the control, respectively. EWP hydrolysates with a parts per thousand 27.0 % degree of hydrolysis obtained with heat pretreatment and ultrasound pretreatments under optimal conditions were further separated by sequential ultrafiltration into 4 hydrolysate fractions ( lt 1, 1-10, 10-30 and gt 30 kDa) which were investigated for protein content, peptide yield and antioxidant activity. The hydrolysis after heat pretreatment generated more peptides lt 1 kDa (19.04 +/- A 1.02 %) than ultrasound pretreatment did (11.90 +/- A 0.53 %), whereas the proportion of peptides lt 10 kDa were higher in the second case (28.80 +/- A 0.07 vs. 20.46 +/- A 0.39 %). The fraction obtained by the ultrasound pretreatment containing peptides with a molecular weight between 1 and 10 kDa demonstrated the strongest ABTS radical scavenging efficacy among the fractions (97.54 +/- A 0.30) with IC50 value of 4.31 mg/mL. Compared with single-enzyme processes, the two-stage enzymatic processes

High energy consumption during freeze drying (FD) is a major concern that limits its application on common food product manufacturing. In this research, fresh duck egg white protein (FDEWP) powder and desalted duck egg white protein (DDEWP) powder were obtained by a combined two-stage tandem drying technologies (FD and microwave–vacuum drying [MVD]) in order to reduce energy consumption while maintaining good product quality. The results showed that the drying time for the FDEWP and DDEWP powders was significantly decreased by FDþMVD compared to those obtained by the FD-only process. The FDEWP powders dried by FDþMVD had a better color (higher L and lower b), lower apparent density, and lower foaming stability but higher emulsifying index than those dried by FD only. The DDEWP powder dried by FDþMVD had a product quality similar to that of FDEWP powder, suggesting that the DDEWP powder could be widely used as a food ingredient.

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., Proteini belanceta spadaju u veoma kvalitetne proteine zbog svog jedinstvenog aminokiselinskog sastava. Međutim, veća komercijalna primena hidrolizata proteina belanceta je ograničena usled neadekvatnog procesnog tretmana pri obradi i sterilizaciji belanceta termičkim tretmanom kao i hemijskoj hidrolizi proteina, koji dovode do značajne promene boje, ukusa, funkcionalnosti i nutritivnih svojstava proizvoda. Cilj ovog rada je bio da se ispita mogućnost primene netermičkih tretmanima, kao što su sonikacija i tretman visokim pritiskom, da bi se unapredila enzimska hidroliza proteina belanceta i omogućilo dobijanje hidrolizata sa antioksidativnom aktivnošću. Pokazano je da tretiranje proteina belanceta ultrazvukom pod određenim uslovima dovodi do njihove kasnije poboljšane hidrolize alkalazom, dok procesiranje belanceta visokim pritiskom ima negativan uticaj na aktivnost alkalaze. Antioksidativna aktivnost dobijenih hidrolizata je povećana nakon pretretmana ultrazvukom na pH 8,3. Tako, kombinacija pretretmana proteina belanceta ultrazvukom na pH 8,3 i njihova sukcesivna hidroliza alkalazom na 50°C i pri pH 8,0 se pokazala kao efikasna alternativna metoda za dobijanje hidrolizata proteina belanceta sa unapređenim funkcionalnim svojstvima i biološkom aktivnošću.

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., Proteini belanceta spadaju u veoma kvalitetne proteine zbog svog jedinstvenog aminokiselinskog sastava. Međutim, veća komercijalna primena hidrolizata proteina belanceta je ograničena usled neadekvatnog procesnog tretmana pri obradi i sterilizaciji belanceta termičkim tretmanom kao i hemijskoj hidrolizi proteina, koji dovode do značajne promene boje, ukusa, funkcionalnosti i nutritivnih svojstava proizvoda. Cilj ovog rada je bio da se ispita mogućnost primene netermičkih tretmanima, kao što su sonikacija i tretman visokim pritiskom, da bi se unapredila enzimska hidroliza proteina belanceta i omogućilo dobijanje hidrolizata sa antioksidativnom aktivnošću. Pokazano je da tretiranje proteina belanceta ultrazvukom pod određenim uslovima dovodi do njihove kasnije poboljšane hidrolize alkalazom, dok procesiranje belanceta visokim pritiskom ima negativan uticaj na aktivnost alkalaze. Antioksidativna aktivnost dobijenih hidrolizata je povećana nakon pretretmana ultrazvukom na pH 8,3. Tako, kombinacija pretretmana proteina belanceta ultrazvukom na pH 8,3 i njihova sukcesivna hidroliza alkalazom na 50°C i pri pH 8,0 se pokazala kao efikasna alternativna metoda za dobijanje hidrolizata proteina belanceta sa unapređenim funkcionalnim svojstvima i biološkom aktivnošću.

An ultrasound-assisted liquefaction as a pretreatment for bioethanol production by simultaneous saccharification and fermentation (SSF) of corn meal using Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. Ultrasound pretreatment (at a frequency of 40 kHz) was performed at different sonication times and temperatures, before addition of liquefying enzyme. An optimal duration of the treatment of 5 min and sonication temperature of 60 degrees C were selected, taking into account glucose concentration after the liquefaction step. Under the optimum conditions an increase of glucose concentration of 6.82% over untreated control sample was achieved. Furthermore, the SSF process kinetics was assessed and determined, and the effect of ultrasound pretreatment on an increase of ethanol productivity was investigated. The obtained results indicated that the ultrasound pretreatment could increase the ethanol concentration by 11.15% (compared to the control sample) as well as other significant process parameters. In this case, the maximum ethanol concentration of 9.67% w/w (which corresponded to percentage of the theoretical ethanol yield of 88.96%) was achieved after 32 h of the SSF process. A comparison of scanning electron micrographs of the ultrasound-pretreated and untreated samples of corn meal suspensions showed that the ultrasound stimulated degradation of starch granules and release of glucose, and thereby accelerated the starch hydrolysis due to the cavitation and acoustic streaming caused by the ultrasonic action.

An ultrasound-assisted liquefaction as a pretreatment for bioethanol production by simultaneous saccharification and fermentation (SSF) of corn meal using Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. Ultrasound pretreatment (at a frequency of 40 kHz) was performed at different sonication times and temperatures, before addition of liquefying enzyme. An optimal duration of the treatment of 5 min and sonication temperature of 60 degrees C were selected, taking into account glucose concentration after the liquefaction step. Under the optimum conditions an increase of glucose concentration of 6.82% over untreated control sample was achieved. Furthermore, the SSF process kinetics was assessed and determined, and the effect of ultrasound pretreatment on an increase of ethanol productivity was investigated. The obtained results indicated that the ultrasound pretreatment could increase the ethanol concentration by 11.15% (compared to the control sample) as well as other significant process parameters. In this case, the maximum ethanol concentration of 9.67% w/w (which corresponded to percentage of the theoretical ethanol yield of 88.96%) was achieved after 32 h of the SSF process. A comparison of scanning electron micrographs of the ultrasound-pretreated and untreated samples of corn meal suspensions showed that the ultrasound stimulated degradation of starch granules and release of glucose, and thereby accelerated the starch hydrolysis due to the cavitation and acoustic streaming caused by the ultrasonic action.