• Food Science and Biotechnology
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• v.17 no.4
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• pp.873-877
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• 2008

Native soy protein isolate (SPI) was hydrolyzed with 4 different proteolytic enzymes, including bromelain, papain, Neutrase, and Flavourzyme. SPI hydrolysates with the degree of hydrolysis (DH) in range of 6 to 15% were prepared by each enzyme. The angiotensin 1 converting enzyme (ACE) inhibitory and the antioxidant activities of the SPI hydrolysates, such as superoxide dismutase-like activity and inhibition of the linoleic acid autoxidation, were evaluated. Overall, as the DH increased, all evaluated bioactivities of the SPI hydrolysates significantly increased. The significantly highest ACE inhibitory and antioxidant activities were found in hydrolysates made with papain and bromelain, respectively. SPI hydrolysates by Flavourzyme showed the significantly lowest activity in all tested bioactivities. The results suggested that ACE inhibitory and antioxidant activities of SPI hydrolysates were determined by the DH and by the enzyme used.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.66-69
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• 2003

An angiotensin converting enzyme (ACE) inhibitory peptide was isolated and purified from the hydrolysates of duck meat protein. Duck meat protein was hydrolyzed using trypsin at 37$^{\circ}C$ for 2 hrs. An ACE inhibitory peptide was purified using membrane filtration, anion exchange chromatography, gel permeation chromatography, fast protein liquid chromatography, normal phase HPLC. The purified inhibitory peptide was identified to be a tetrapeptide, Glu-Asp-Leu-Glu having $IC_{50}$/ value of 85.9 $\mu$M.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.9
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• pp.1166-1171
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• 2006

This study was performed to investigate the effect of silk protein hydrolysates on blood glucose in diabetic mice (C57BL/KsJ db/db). The silk protein hydrolysates hydrolyzed by protease contains 87.52% of peptides of which molecular weight was below 2,000 dalton. The content of free amino acids was 14.80 g/100 g silk protein hydrolysates and major free amino acids were Pro, Thr, Arg and Ala. Silk protein hydrolysates were administered to the animals for 9 weeks at doses of 0.2, 0.5% and 0.8% solution. The body weight increase in the 0.5 and 0.8% fed groups were higher than control group. Food and water intake in the silk protein hydrolysates fed groups were lower than control group. The weight of liver was not different among groups, while the weight of kidney in control group was higher than silk protein hydrolysates fed groups. The blood glucose level in silk protein hydrolysates fed groups was lower than control group. In the glucose tolerance test, the blood glucose level in control group was the highest at 15 minutes after glucose injection while those in silk protein hydrolysates fed groups were the highest at 30 minutes. Results in this study suggest that silk protein hydrolysates show hypoglycemic effect in C57BL/KsJ db/db mice.

• Food Science of Animal Resources
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• v.23 no.1
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• pp.63-69
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• 2003

This experiment was carried out to study changes in solubility and emulsifying properties of whey protein. Whey protein hydrolysates were obtained from tryptic hydrolysis of whey protein concentrate at pH 8.0 and 37$^{\circ}C$ for 6 hours. Emulsifying activity of whey protein hydrolysate was highest at 4 hours of hydroysis and at 5.50% of DH. During hydrolysis of whey protein concentrate with trypsin, ${\alpha}$-lactalbumin was not easily broken down. But ${\beta}$-lactoglobulin was hydrolysed rapidly from the early stage of hydrolysis, producing several low molecular weight peptides, which have to participate in increasing emusifying activity. The solulbility of hydyolysates tended to increase depending on hydrolysis time; however, there was a gradual decrease after 5 hours. The hydrolysate had a minimum solubility near the isoelectric point range (pH 4∼5). The more hydrolysed the whey protein concentrates, the more soluble they are near the pl. They aye also more soluble above pH 6. Emulsifying activity of hydrolysates showed similar results to solubility. Creaming stability gradually increased when hydrolysis increased, increasing rapidly above pH 8 after 4 hours of hydrolysis.

• Journal of Life Science
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• v.10 no.5
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• pp.436-446
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• 2000

This study was conducted to investigate the effects of different dietary enzymatic hydrolysates using squid and mackerel by-product on feed efficiency, growth and chemical composition in Korean rockfish (Sebastes schlegeli) after a eight weeks feeding experiment. Effects on the weight gain and feed efficiency in the enzymatic hydrolysates added groups were very effective. Weight gain were significantly higher in the squid hydrolysates whole added group than in the other groups. Moisture and crude ash contents of muscle were not significantly affected by hydrolysates supplementation in all groups. Crude protein and lipid contents of muscle were increased after eight weeks feeding trial. Amino acid contents of muscle were higher in squid hydrolysates whole added group than in the other groups. Amino acids were not affected by hydrolysates supplementation in all groups. Fatty acid contents of muscle were increased after eight weeks growth trial. Fatty acids were not significantly different in the dietary groups.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.1
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• pp.1-5
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• 2014

The diagnosis and treatment of cow's milk protein allergy (CMPA) is still a challenge. A systematic literature search was performed using Embase, Medline, The Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Clinical Trials for the diagnosis and treatment of cow's milk allergy (CMA). Since none of the symptoms of CMPA is specific and since there is no sensitive diagnostic test (except a challenge test), the diagnosis of CMPA remains difficult. A "symptom-based score" is useful in children with symptoms involving different organ systems. The recommended dietary treatment is an extensive cow milk based hydrolysate. Amino acid based formula is recommended in the most severe cases. However, soy infant formula and hydrolysates from other protein sources (rice) are gaining popularity, as they taste better and are cheaper than the extensive cow's milk based hydrolysates. Recent meta-analyses confirmed the safety of soy and estimate that not more than 10-15% of CMPA-infants become allergic to soy. An accurate diagnosis of CMA is still difficult. The revival of soy and the development of rice hydrolysates challenge the extensive cow's milk based extensive hydrolysates as first option and amino acid formula.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.1
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• pp.115-122
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• 2014

This study investigated on the effects of adding mechanically deboned chicken meat (MDCM) hydrolysates on the quality properties of imitation fish paste (IFP) during storage. IFP was prepared from Alaska Pollack, spent laying hens surimi and protein hydrolysates which were enzymatically extracted from MDCM. The study was designed as a $3{\times}4$ factorial design with three MDCM hydrolysate content groups (0%, 0.4%, and 0.8%) and four storage times (0, 2, 4, and 6 weeks). Addition of MDCM hydrolysates increased crude fat content but lowered water content (p<0.05). The breaking force of IFP, an indicator of gel formation, increased in treated groups compared to control (p<0.05). Angiotensin I-converting enzyme (ACE) activity was inhibited and free radical scavenging activity increased with increasing MDCM hydrolysate content (p<0.05). In conclusion, the addition of MDCM to IFP improves gel characteristics. Additionally, protein hydrolysates from MDCM serve as a potential source of ACE inhibiting peptides.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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• pp.19-27
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• 2015

The objective of the current study was to evaluate the inhibitory and antioxidant activities of powdered katsuobushi (dried bonito) protein hydrolysates and their corresponding fractions. The powdered katsuobushi (dried bonito) hydrolysates were obtained by enzymatic hydrolysis using Alcalase, ${\alpha}$-chymotrypsin, Neutrase, pepsin, papain, and trypsin. The antioxidant efficacy of the respective hydrolysates were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, and alkyl radical-scavenging activities. Among the hydrolysates, the peptic-derived hydrolysate exhibited the highest antioxidant activity compared to other enzymatic hydrolysates. Therefore, the peptic-derived hydrolysate was further analyzed, and was found to contain an active peptide with an amino acid sequence identified as Pro-Met-Pro-Leu-Asn-Ser-Cys (756 Da). The purified peptides from powdered katsuobushi (dried bonito) had an $EC_{50}$ value of $105.82{\mu}M$, and exhibited an inhibitory effect against DNA oxidation induced by hydroxyl radicals. Taken together, these results suggests that powdered katsuobushi (dried bonito) could be used as a natural antioxidant in functional foods and prevent oxidation reactions in food processing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.435-441
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• 2017

The present study was carried out to evaluate the applicability of Tenebrio molitor larvae (mealworm) as a health functional food material in order to contribute to the development of the domestic insect industry and health functional food industry. Protein hydrolysates were prepared from mealworm powder by enzymatic hydrolysis using five different proteases (alcalase, bromelain, flavourzyme, neutrase, and papain), and the hydrolysates were then tested for their antioxidant activities. Based on available amino group contents and sodium dodecyl sulphate-polyacrylamide gel electrophoresis analyses, mealworms treated with alcalase ($4,781.39{\mu}g/mL$), flavourzyme ($5,429.35{\mu}g/mL$), or neutrase ($3,155.55{\mu}g/mL$) for 24 h showed high degree of hydrolysis (HD) value, whereas HD values of bromelain ($1,800{\mu}g/mL$) and papain-treated ($1,782.61{\mu}g/mL$) mealworms were much lower. Protein hydrolysates showing high HD values were further separated into > 3 kDa and ${\leq}3kDa$ fractions by a centrifugal filter system and then lyophilized, and the production yields of the low molecular weight protein hydrolysates (${\leq}3kDa$) by alcalase, flavourzyme, and neutrase were 42.05%, 26.27%, and 30.01%, respectively. According to the RC_{50} values of the protein hydrolysates (${\leq}3kDa$) obtained from three different antioxidant analyses, all three hydrolysates showed similar antioxidant activities. Thus, alcalase hydrolysates showing the highest production yield of low molecular weight protein hydrolysates were further tested for their inhibitory effects on peroxidation of linoleic acid by measuring thiobarbituric acid values, and the results show that peroxidation of untreated linoleic acid increased dramatically during 6 days of incubation. However, pretreatment with the hydrolysates ($100{\sim}800{\mu}g/mL$) significantly inhibited linoleic acid peroxidation in a dose-dependent manner over 6 days.

• Food Science and Preservation
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• v.10 no.1
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• pp.80-88
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• 2003

In order to establish the enzymatic hydrolysis system improving of taste and flavor in the preparation of soy protein hydrolysates using the enzymes with excellent hydrolytic ability and different hydrolysis pattern of soy protein, Degree of hydrolysis(DH) and surface hydrophobicity under the optimal conditions of enzyme reaction, hydrolysis patterns by the SDS electrophoresis and sensory evaluation of soy protein hydrolysates by enzyme reactions were investigated. Four enzyme reactions were highly activated at pH 7.0, 45$^{\circ}C$ under the optimal conditions. As result of changes on the pattern of soy-protein hydrolysates by SDS-electrophoresis, high molecular peptides of hydrolysates by No. 5(Mucor circinelloides M5) and No. 16(Bacillus megaterium B16) enzymes were slowly decrease and 66KD band of these were remained after 3hours reaction. Production of low molecular peptides of hydrolysates by No. 4(Aspergillus oryzae M4) and No. 95(Bacillus subtilis YG 95) enzymes were remarkably detected during the proceeding reactions. As results of HPLC analysis, low molecular peptides of 15∼70KD were mainly appeared during the proceeding enzyme reactions. And, the more DH was increased, the more SDS-surface hydrophobicity was decreased. Hydrolysates by No. 4 enzyme was not only the highest DH of all hydrolysates, but the strongest bitter taste in a sensory evaluation. Sweat taste among the hydrolysates showed little difference. But, when combinative enzymes were treated, combinative enzyme of No. 4(Aspergillus oryzae M4)and No. 16(Bacillus megaterium B16) showed the strongest sweat taste. In conclusion, we assumed that it will be possible to prepare the hydrolysates having functionality when soy-protein were hydrolyzed by these specific enzymes.