Bioactive properties of enzymatic hydrolysates from abdominal skin gelatin of yellowfin tuna (Thunnus albacares)

Gelatin (90.6 ± 0.1%) was optimally prepared by response surface methodology from yellowfin tuna (Thunnus albacares, YT) abdominal skin. To investigate bioactive properties of enzymatic hydrolysates from the abdominal skin gelatin (ASG), ASG was hydrolysed with alcalase, protamex, neutrase and flavourzyme as affected by hydrolysis time. Antioxidant, nitrite scavenging and angiotensin‐I converting enzyme (ACE) inhibitory activities of the hydrolysates were determined. Antioxidant activities of the hydrolysates were found through linoleic acid peroxidation inhibitory effects. Alcalase‐derived hydrolysates (AHs) were more effective than others in metal ions chelating, superoxide anion scavenging and hydroxyl radical scavenging activities (P < 0.05). AHs showed significantly stronger nitrite scavenging activities (44.4–60.7%) than others (P < 0.05). Fraction A from AH showed strong ACE inhibitory activity (IC₅₀ of 0.75 mg mL^?1). These results suggest that YT ASG and its enzymatic hydrolysates could be functional food and/or pharmaceutical ingredients with potent antioxidant, anticarcinogenic and antihypertensive benefits.     

Optimisation of antioxidant hydrolysate production from sweet potato protein and effect of in vitro gastrointestinal digestion

In this study, response surface methodology (RSM) was applied to optimise antioxidant hydrolysate production from sweet potato protein (SPP). The effects of enzyme‐to‐substrate ratio, pH value and reaction temperature on ·OH radical scavenging activity and Fe²⁺‐chelating activity of antioxidant hydrolysates from SPP were investigated. The maximum ·OH radical scavenging activity (40.10%) and Fe²⁺‐chelating activity (74.37%) of SPP hydrolysates (SPPH) were obtained at an enzyme‐to‐substrate ratio of 4%, pH value of 7.8 and reaction temperature of 57 °C, which was in agreement with the predicted value (40.11% and 74.83%, respectively) estimated by RSM. The simulated in vitro gastrointestinal digestion (GID) dramatically modified molecular weights distribution, increased peptide (<3 kDa) concentration and highly retained antioxidant activity of SPPH, indicating potentially utilisation of SPPH as a functional supplement in food system.     

Inhibition of the in vitro activities of α-amylase, α-glucosidase and pancreatic lipase by yellow field pea (Pisum sativum L.) protein hydrolysates

The aim of this work was to produce yellow field pea protein-derived peptides as inhibitors of α-amylase, α-glucosidase and pancreatic lipase activities. A pea protein concentrate was hydrolysed with alcalase, chymotrypsin, pepsin or trypsin and the hydrolysates separated into different fractions (<1, 1–3, 3–5, 5–10 kDa) by membrane ultrafiltration. Peptide sequence analysis showed that the alcalase hydrolysate had higher levels of di- and tripeptides when compared with the chymotrypsin, pepsin and trypsin hydrolysates. The peptide fractions inhibited α-amylase and α-glucosidase activities at levels that were similar to the unfractionated hydrolysates. The peptides were more active against α-amylase (inhibition at μg level) than α-glucosidase (mg level). In contrast, the fractionated peptides had reduced ability (IC₅₀ >4.2 mg mL⁻¹) when compared with the unfractionated hydrolysate (IC₅₀ <4.2 mg mL⁻¹) to inhibit lipase activity. Enzyme kinetic studies revealed that the peptides reduced α-amylase activity through competitive inhibition. However, inhibition of α-glucosidase activity was non-competitive.     

Antioxidant function of tea dregs protein hydrolysates in liposome–meat system and its possible action mechanism

Tea dregs possess abundant proteins, and the objective of this study was to investigate the antioxidant activity of tea dregs protein hydrolysate with limited hydrolysis by protamex and its possible action mechanism. Tea dregs protein was hydrolysed by alcalase, protamex or neutrase. The hydrolysis condition was optimised, and the hydrolysate was characterised for 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) radical‐scavenging activity, hydroxyl radical‐scavenging activity and antioxidant activity in linoleic acid (LA) system and in chicken products. Tea dregs protein hydrolysate (TDPH) was formulated (0.1%, 0.5%, 1.0%, w/w) into chicken products to determine in situ antioxidant efficacy. Thiobarbituric acid‐reactive substances (TBARS) and peroxide value (POV) formed in chicken products during storage (4 °C, 0–7 days) were analysed. Results showed that the optimum hydrolysis condition was at 50 °C, pH 7.0 for 20 min, and the concentration of tea dregs protein was 1.5%; ratio of protamex to substrate was 6000 U g^?1. The radical‐scavenging ratio of TDPH to 1,1‐diphenyl‐2‐picryl hydrazyl (DPPH) was 90.30% at the concentration of 0.1 mg mL^?1 and that to hydroxyl radical was 65.18% at the concentration of 1.0 mg mL^?1. Moreover, it also showed strong antioxidant activity both in linoleic acid (LA) system and in chicken products. The molecular weight distribution of tea dregs hydrolysates was determined by nanofiltration tubular membrane, and the protein hydrolysates with molecular weight above 8000 Da had more effective antioxidant activity. The radical‐scavenging activities to DPPH and hydroxyl radical were 85.72% at 0.1 mg mL^?1 and 71.52% at 1.0 mg mL^?1, respectively. These findings suggest that the enzymatic hydrolysate of tea dregs protein probably possesses the specific peptides/amino acids which could stabilise or terminate the radicals through donating hydrogen. In addition, the hydrolysate could form a physical barrier around the fat droplets.     

The influence of heat treatment of chickpea seeds on antioxidant and fibroblast growth‐stimulating activity of peptide fractions obtained from proteins digested under simulated gastrointestinal conditions

This study presents the effect of heat treatment of chickpea seeds on biological activity of peptides obtained by in vitro gastrointestinal digestion. The most significant antiradical activity against ABTS^+? expressed as IC₅₀ value was observed for 3.5‐ to 7‐kDa peptide fraction from TC hydrolysate (41.01 μg mL^?1). In turn, peptide fraction of 3.5–7.0 kDa obtained from raw chickpea seeds hydrolysate showed the highest antiradical activity against DPPH^? and Fe²⁺ chelating activity with IC₅₀ value of 20.94 and 52.53 μg mL^?1, respectively. The highest Cu²⁺ chelating activity was observed for peptides obtained from TC hydrolysate (IC₅₀ = 56.60 μg mL^?1). Peptide fraction <3.5 kDa from TC hydrolysate demonstrated the most significant reducing power (0.362 A₇₀₀/μg mL^?1). The peptide fraction of 3.5–7 kDa from TC hydrolysate also showed the highest fibroblast growth‐stimulating activity. These results indicated that the heat treatment process has no significant effect on antiradical activity against DPPH^? and Fe²⁺ chelating ability of peptides.     

Separation of angiotensin I‐converting enzyme inhibitory peptides from bovine connective tissue and their stability towards temperature,pH and digestive enzymes

Bovine collagen was isolated from connective tissue, a by‐product in the meat processing industry and characterised by SDS‐PAGE. Alcalase and papain were employed to generate collagen hydrolysates with different degree of hydrolysis (DH). In vitro angiotensin I‐converting enzyme (ACE) inhibitory activities were evaluated and the two most potent hydrolysates from each enzyme were separated by two‐step purification. Both alcalase‐catalysed and papain‐catalysed hydrolysates exhibited strong ACE inhibitory capacities with IC₅₀ values of 0.17 and 0.35 mg mL^?1, respectively. Purification by ion‐exchange chromatography and gel filtration chromatography revealed higher ACE inhibitory activities in one fraction from each enzyme with IC₅₀ values of 3.95 and 7.29 μg mL^?1. These peptide fractions were characterised as 6‐12 amino acid residues by MALDI‐TOF/MS. The peptides retained their activity (>90%) after exposure to processing temperature and pH and in vitro simulated gastrointestinal digestion. The present results demonstrated that collagen peptides can be utilised for developing high value‐added ingredients, for example ACE inhibitory peptides.     

Antioxidant activities of the fractionated protein hydrolysates from heat stable defatted rice bran

The hydrolysates from heat stable rice bran (HSDRB) treated by Alcalase 2.4L and Protease 500G were desalted and fractionated by hydrophobicity using a nonpolar, styrene divinylbenzene resin and macroporous adsorption resin DA201‐C. The antioxidant activities of HSDRB hydrolysates (HSDRBH) eluted by 25%, 50%, 75% and 100% ethanol were investigated using 2, 2‐di (4‐tertoctylphenyl)‐1‐picrylhydrazyl free radical‐scavenging activity assay, reducing power assay, ferrous ion‐chelating activity assay and lipid peroxidation inhibition assay. The HSDRBH‐75 had the highest reducing power assay and inhibition ratio of linoleic acid autoxidation, which might be associated with reduced molecular weight, amino acid composition and hydrophobicity. The highest metal‐chelating activity of four different fractions (at the concentration of 4 mg mL^?1) had a positive correlation (r = 0.768, P = 0.116) with the total content of basic amino acid (Lys, Arg, and His) and a negative correlation (r = ?0.886, P = 0.057) with the range of molecular weight (Mw < 1000 Da). The HSDRBH‐75 had the highest antioxidant activities in many assays, which suggests that it may become a good natural antioxidant as a food additive.     

Antioxidant and melanogenesis‐inhibitory activities of collagen peptide from jellyfish (Rhopilema esculentum)

BACKGROUND: Jellyfish collagen was hydrolysed with trypsin and properase E, and jellyfish collagen peptide (JCP) was purified from the enzymatic hydrolysate using ion exchange chromatography and gel filtration. The antioxidant activity of JCP in a linoleic acid emulsion system, its superoxide anion‐ and hydroxyl radical‐scavenging activities and its copper‐chelating ability were evaluated in vitro. Initial investigations of JCP's ability to inhibit melanogenesis were carried out using cultured B16 melanoma cells. RESULTS: The molecular weight distribution of JCP was from 400 to 1200 Da. Amino acid analysis showed that JCP was rich in Gly, Pro, Ser, Ala, Glu and Asp and had a total hydrophobic amino acid content of 384.2 g kg^?1. JCP showed high antioxidant activity (IC₅₀147.8 µg mL^?1), superoxide anion‐scavenging activity (IC₅₀21.9 µg mL^?1), hydroxyl radical‐scavenging activity (IC₅₀16.7 µg mL^?1) and copper‐chelating ability (IC₅₀88.7 µg mL^?1) in vitro. It also significantly inhibited intracellular tyrosinase activity, decreased melanin content and enhanced glutathione synthesis (P < 0.05). Furthermore, JCP decreased intracellular cAMP levels and suppressed tyrosinase mRNA expression. CONCLUSION: Based on the results of this study, JCP exerts anti‐melanogenic actions via its antioxidant properties and copper‐chelating ability. JCP could be used as a natural skin‐lightening agent in the medicine and food industries. Copyright © 2009 Society of Chemical Industry     

Evaluation of free radical‐scavenging activities of sweet potato protein and its hydrolysates as affected by single and combination of enzyme systems

To evaluate the free radical‐scavenging activities of sweet potato protein (SPP) and its hydrolysates, single enzymes alone (alcalase, neutrase, protamex) or in combination with flavourzyme were employed. Compared with SPP, free radical‐scavenging activities of the resulting hydrolysates were all significantly increased (P < 0.05). Alcalase (ALC) hydrolysates exhibited the highest superoxide, hydroxyl and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical‐scavenging activities (P < 0.05), which was 18.71 ± 0.22, 27.13 ± 0.24 and 90.10 ± 0.15% respectively. Compared with SPP hydrolysates by single enzymes, the hydrolysates obtained by combination of enzyme systems exhibited higher degree of hydrolysis, but lower free radicals scavenging activities. In addition, the content of several antioxidant amino acid residues, such as His, Met, Tyr and Phe, in ALC hydrolysates was much higher compared with SPP and other hydrolysates using amino acids composition assay. The results suggested that peptides with free radical‐scavenging activity could be released from entire SPP chain via moderate enzymatic hydrolysis.     

The effect of enzymatic hydrolysis on the biological properties of Oenothera biennis,Borago officinalis and Nigella sativa seedcake by‐products from oil pressing

The biological properties of ethanolic (50%, v/v) extracts from Oenothera biennis, Borago officinalis, Nigella sativa seedcake before and after enzymatic hydrolysis by alpha‐amylase (EC 3.2.1.1) from Aspergillus oryzae, beta‐glucosidase (EC 3.2.1.21) and beta‐glucanase (EC 3.2.1.6) from Aspergillus niger combinations in a ratio of 1:1:1 were investigated. Total phenolic, flavonoid and reducing sugar content for O. biennis extract after enzymatic hydrolysis was, respectively, 0.5, 1.5 and 2 times higher in comparison with nonhydrolysed extract. Iron‐chelating and radical‐scavenging activity of O. biennis seedcake extract after hydrolysis (IC₅₀ = 0.076 mg mL^?1 and IC₅₀ = 0.050 mg mL^?1) was at a similar level as that nonhydrolyeed (IC₅₀ = 0.070 mg mL^?1 and IC₅₀ = 0.065 mg mL^?1). The antioxidant activity was two times higher after hydrolysis than before enzymatic hydrolysis of O. biennis seedcake extract. Also strong elastase inhibition activity has been shown to O. biennis seedcake extract before (IC₅₀ = 0.095 mg mL^?1) and after enzymatic hydrolysis (IC₅₀ = 0.07 mg mL^?1), respectively. Oenothera biennis and B. officinalis seedcake extracts before and after hydrolysis have stronger antibacterial activity against Pseudomonas aeruginosa strain in comparison with N. sativa seedcake.     

Chemical composition,antioxidant activity and anti‐lipase activity of Origanum vulgare and Lippia turbinata essential oils

This study reported the chemical composition, phenolic content, antioxidant and anti‐lipase activity of oregano and Lippia essential oils. The major compounds found in oregano essential oil were γ‐terpinene (32.10%), α‐terpinene (15.10%), p‐cymene (8.00%) and thymol (8.00%). In Lippia essential oil, α‐limonene (76.80%) and 1,8‐cineole (4.95%) represented the major compounds. Oregano essential oil had higher phenolic content (12.47 mg gallic acid mL^?1) and DPPH scavenging activity (IC₅₀ 0.357 μg mL^?1) than Lippia essential oil (7.94 mg gallic acid mL^?1 and IC₅₀ 0.400 μg mL^?1, respectively). Both essential oils had similar antioxidant indexes (about 1.2) determined by Rancimat. Moreover, oregano essential oil had also higher anti‐lipase activity (IC₅₀ 5.09 and 7.26 μg mL^?1). Higher phenolic content in the essential oils was related with higher scavenging and anti‐lipase activities. Oregano and Lippia essential oils could be used as natural antioxidants on food products.     

Contribution of different molecular weight fractions to anticancer effect of sweet potato protein hydrolysates by six proteases on HT‐29 colon cancer cells

The contribution of different molecular weight fractions to anticancer effect of sweet potato protein hydrolysates (SPPH) by six proteases on HT‐29 colon cancer cells was investigated. SPPH prepared by six proteases showed certain antiproliferation effect on HT‐29 cells. Compared with other five proteases, SPPH by Alcalase exhibited the highest antiproliferation effect with the lowest IC₅₀ value of 119.72 μg mL^?1. SPPH by Alcalase was further separated into four fractions (>10, 5–10, 3–5 and <3 kDa), and <3 kDa fractions showed the strongest antiproliferation effect, which was 43.87% at 100 μg mL^?1 (P < 0.05). The <3 kDa fractions could cause G2/M cell cycle arrest with increased p21 expression and induce apoptosis via decreasing Bcl‐2 expression, increasing Bax expression and inducing caspase‐3 activation in HT‐29 cells. In addition, <3 kDa fractions could significantly inhibit cell migration of HT‐29 cells. Thus, SPPH might be potentially used as a natural supplement in functional foods.     

Effects of physicochemical factors and in vitro gastrointestinal digestion on antioxidant activity of R‐phycoerythrin from red algae Bangia fusco‐purpurea

R‐phycoerythrin (R‐PE) was purified from the red algae Bangia fusco‐purpurea after 35–50% ammonium sulphate fractionation followed by ion‐exchange column chromatography on DEAE‐Sepharose, resulting in a purity (A₅₆₅/A₂₈₀) ratio of 5.1. The circular dichroism spectroscopy results suggested that the structure of R‐PE is predominately helical. The antioxidant activity of R‐PE was studied and revealed changes in conformation and antioxidant activity at different temperatures and pH values. After in vitro‐simulated gastrointestinal (GI) digestion of R‐PE, the scavenging activity of ABTS radical (EC₅₀, 769.9 μg mL^?1), DPPH radical (EC₅₀, 421.9 μg mL^?1), hydroxyl radical (EC₅₀, 32.4 μg mL^?1) and reducing power (A₇₀₀ = 0.5, 625.8 μg mL^?1) were measured. Gel filtration chromatography analysis showed that the molecular weight distribution of the final GI digest that still contained high antioxidant activity was <3 kDa. Our present results indicate that digestion‐resistant antioxidant peptides of R‐PE may be obtained by in vitro GI proteinases degradation.     

Activities and sequences of the angiotensin I‐converting enzyme (ACE) inhibitory peptides obtained from the digested lentil (Lens culinaris) globulins

The aim of this study was the identification of potentially bioaccessible ACE‐inhibitory peptides obtained by in vitro gastrointestinal digestion of lentil globulins. ACE‐inhibitory peptides were purified by ion exchange chromatography and gel filtration. After the first step of purification, three peptide fractions with potential antihypertensive properties were obtained and the highest inhibitory activity was determined for the fraction 5 (IC₅₀ = 0.02 mg mL^?1). This fraction was separated on Sephadex G10, and six peptide fractions were obtained. The peptides of fraction (5‐F) with the highest potential antihypertensive activity (IC₅₀ = 0.13 mg mL^?1) were identified using ESI‐MS/MS. The sequences of peptides were KLRT, TLHGMV and VNRLM. Based on Lineweaver–Burk plots for the fraction 5‐F, the kinetic parameters as K_m (1.24 mm ), V_max (0.012 U min^?1), K_i (0.12 mg mL^?1) and mode of inhibition were determined.     

Antioxidant potential of protein‐rich serum from farmed swan goose (Anser cygnoides): in vitro and in vivo evaluation of antioxidant effects

As food ingredient, Anser cygnoides is farmed in large scale; however, its blood is underused. The characteristics, stability and antioxidant activities of P owder of farmed C ygnoides S erum (FACSP) were investigated. Results showed that FACSP was protein‐rich and displayed satisfactory antioxidant activities. In vitro analysis indicated that the IC₅₀ values of 2, 2′‐azinobis‐(3‐ethylbenz‐thiazoline‐6‐sulphonate), 1,1‐diphenyl‐2‐picrylhydrazyl and hydroxyl radicals were 1.56, 2.76 and 39.55 mg mL^?1, respectively. In vivo experiment showed that the activity of total superoxide dismutase and content of glutathione of the FACSP‐treated groups were enhanced, and the contents of malondialdehyde and protein carbonyl were decreased. The parameters of 400 and 800 mg kg^?1 bw day^?1 dose groups were equally or approximately to vitamin C. The FACSP shows potential as an antioxidant functional food at a dose of 400 mg kg^?1 bw day^?1.     

Enzymatic hydrolysis of hemp (Cannabis sativa L.) protein isolate by various proteases and antioxidant properties of the resulting hydrolysates

Enzymatic hydrolysis of hemp protein isolate (HPI) by six proteases (alcalase, flavourzyme, neutrase, protamex, pepsin and trypsin) and antioxidant activities of the resulting hydrolysates, obtained for 2 and 4 h were investigated. The yield of trichloroacetic acid (TCA)-soluble peptides (Y_sp), protein composition and surface hydrophobicity (H_o) of the hydrolysates were evaluated. The results showed that the hydrolysates exhibited varying DPPH radical scavenging (with lowest IC₅₀, ∼2.3 mg/mL) and Fe²⁺⁺ chelating (with lowest IC₅₀ of 1.6–1.7 mg/mL) abilities and reducing power (with highest absorbance at 700 nm of 0.31–0.35), depending on their Y_sp and H_o values. The DPPH radical scavenging and Fe²⁺⁺ chelating abilities of the hydrolysates were positively correlated with their Y_sp or H_o values. The results suggest that enzymatic hydrolysis can be used as an effective technique to produce high value-added products of hemp proteins.     

Hypolipidaemic and antioxidant capacities of polysaccharides obtained from Laminaria japonica by different extraction media in diet‐induced mouse model

This study shows the industrial feasibility of using aqueous methods to produce antioxidative and hypolipidaemic polysaccharides from Laminaria japonica (LJP). Comparison was firstly made among the polysaccharides prepared using different extraction media, that is water alone (LJPW) and citric acid (LJPC), sulphuric acid, hydrochloric acid and phosphoric acid. LJPC enabled the highest extract yield (~11% dry weight), bile salt adsorption rate (~59% dry weight), ABTS radical scavenging activity (IC₅₀ value 1.06 mg mL^?1) and ORAC antioxidant activity (341.87 μmol Trolox g^?1). In animal trial using diet‐induced high‐fat mice, oral administration of LJP produced with citric acid (LJPC) at a high dose (200 mg kg^?1 body mass per day) enabled significantly higher serum HDL‐C, lower LDL‐C/HDL‐C and unaltered LDL‐C, whilst a medium dose (100 mg kg^?1 body mass per day) significantly decreased LDL‐C. Administration of LJP produced with water (200 mg kg^?1 body mass per day) significantly lowered serum LDL‐C. Therefore, LJP may provide dose‐dependent pharmacological and therapeutic effects to combat atherosclerosis through their hyperlipidaemic and antioxidant properties.     

Antioxidant and anti‐hypertensive activity of anthocyanin‐rich extracts from hulless pigmented barley cultivars

Anthocyanin‐rich acetone extracts of barley grain of four hulless pigmented genotypes were investigated to determine their potential as functional food ingredients. The purple barley cultivar contained 11 anthocyanins, whereas only one anthocyanin, peonidin derivative, was observed in blue, black and yellow barley. The total anthocyanin content of pigmented barley genotypes ranged from 3.2 to 678.5 mg kg^?1 in whole grain and from 4.5 to 1654.6 mg kg^?1 in bran. The purple barley bran extract gave the highest DPPH radical scavenging capacity, superoxide radical scavenging capacity and total antioxidant activity. The half maximal inhibitory concentration (IC₅₀) of angiotensin I‐converting enzyme (ACE) of anthocyanin‐rich extract of purple barley grain and bran was 8.77 and 4.54 mg mL^?1, respectively. Purple barley appears to have great potential uses for the promotion of human health and development of nutraceuticals and functional foods.     

Antioxidant activities of Rapana venosa meat and visceral mass during simulated gastrointestinal digestion and their membrane ultrafiltration fractions

Rapana venosa (Rv) is an abundant marine snail resource with high content of protein. The antioxidant activities of Rv meat and visceral mass during simulated gastrointestinal (GI) digestion and their membrane ultrafiltration fractions were evaluated. Results indicated that visceral mass possessed stronger antioxidant activities than meat. The simulated GI digestion increased the hydroxyl radical scavenging activity while decreased the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) scavenging activity and reducing power. After membrane ultrafiltration, there were three fractions, that is molecular weight (MW) > 10 kDa, MW 3.5–10 kDa and MW < 3.5 kDa. Fractions with MW > 10 kDa and MW < 3.5 kDa showed the highest hydroxyl, DPPH radical scavenging activity, respectively. Fractions with MW 3.5–10 kDa and MW > 10 kDa showed the highest reducing power for meat and visceral mass, respectively. Rv hydrolysates exhibited significantly higher hydroxyl radical scavenging activity than the positive control vitamin C (Vc) and may serve as useful ingredients for application in food industry nutritional products.     

In vitro antioxidant activities of hydrolysates obtained from Iranian wild almond (Amygdalus scoparia) protein by several enzymes

A protein extract from wild almond was hydrolysed using five different enzymes (pepsin, trypsin, chymotrypsin, alcalase and flavourzyme). The hydrolysates were then assayed for their antioxidant activities. The highest extent of proteolysis was obtained with alcalase (0.35; determined as the change in the absorbance at 340 nm, ΔA₃₄₀) and the lowest was with pepsin (ΔA₃₄₀ = 0.12). Radical scavenging activities obtained by 2, 2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulphonic acid) and ferric‐reducing abilities of the hydrolysates demonstrated that the hydrolysate from alcalase had significantly (P < 0.05) greater antioxidant activity. Analysis of the molecular weight distributions showed that peptides produced by alcalase were smaller than those produced by chymotrypsin, trypsin and flavourzyme. Based on the current study, the hydrolysates produced by alcalase can be suggested as potential antioxidant agents in food industry and for use in functional foods.