• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.435-440
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• 2010

Whey protein concentrate (WPC) is widely used to increase the nutritional and functional properties of food. In this study, the physiochemical and functionality of WPC-30 hydrolysates were examined to evaluate the possibility of application in the food industry. The WPC-30 was manufactured using ultrafiltration and spray-drying, and then hydrolyzed with proteolytic enzyme including alcalase, flavourzyme, nuetrase and protamex. Enzymatic hydrolysis had a significant influence on the physicochemical properties as evident from the increased foaming capacity, solubility. Alcalase caused highest protein hydrolysis (3.26%) and the bitterness. Foaming capacity was largest in WPC-30 hydrolysate treated with flavourzyme. Protein solubility at various levels of pH was highest in protamex-treated WPC-30 hydrolysate. However, the solubility of WPC-30 hydrolysates was significantly improved in alkaline condition than in acidic and neutral conditions. The study revealed that spray dried enzyme modified WPC can be used in various functional food.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.238-243
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• 2005

This study was carried out to understand hyrolytic characteristics of $\beta-casein$ by enzyme in goat milk and to measure the inhibition effect of the ACE of the hydrolysate. In order to conduct the experiment, $\beta-casein$ of goat milk was separated using Mono S HR 5/5, a cation exchange column. The separated $\beta-casein$ was treated with trypsin of animal hydrolysis enzymes, in an effort to verify the characteristics of hydrolysis. The inhibition activity of ACE was measured and the results are as follows. By analyzing the hydrolysate separated from the trypsin-processed $\beta-casein$ of goat milk, the inhibition effect of the ACE was measured trypsin-hydrolyzed $\beta-casein$ demonstrated a $25.36\pm0.79\%$ of inhibition effect and the $IC_{50}$ of the hydrolysate from the trypsin-processed $\beta-casein$ reached $308.7\pm2.77({\mu}g/mL)$.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.228-234
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• 1984

A partial hydrolysis of soybean protein isolate was carried out by using pepsin and trypsin. The degree of hydrolysis was evaluated by chemical analysis, viscometric measurements and gel electrophoresis. The functional properties of the hydrolyzates such as flow behavior, emulsion properties and foaming properties were evaluated. A selective hydrolysis of 11S protein fraction by pepsin was observed from the SDS-PAG electrophoresis. The changes in the molecular weight distribution by different conditions of enzyme hydrolysis were evaluated. The changes in the intrinsic viscosity of the protein hydrolylate by reaction time were highly correlated to the contents of TCA soluble protein and 0.03 M $CaCl_2$ soluble nitrogen. The degree of hydrolysis ($DH_{TCA}$, $DH_{Ca}$) were used to evaluate the effect of enzyme treatment on the functional properties of the hydrolyzate. The apparent viscosity and emulsion capacity and stability of the protein solution decreased as DH increased, while the foaming capacity increased linearly with the increasing DH.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.151.2-152
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• 1998

• Food Science and Preservation
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• v.20 no.3
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• pp.435-439
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• 2013

As byproducts of chicken slaughtering, chicken feathers are produced and mostly discarded without proper treatment, which results in serious environment pollution. Therefore, the appropriate treatment and utilization of chicken feathers are needed. In particular, chicken feathers can be used as protein sources for the preparation of protein hydrolysates, considering that chicken feathers have a large amount of proteins. In this study, chicken feather protein hydrolysates were prepared and their iron-binding peptides were isolated. Chicken feather protein was extracted from feathers of slaughtered chicken, and its hydrolysates were prepared via hydrolysis with Flavourzyme for 8 h. Then the chicken feather protein hydrolysates were ultra-filtered to obtain small peptide fractions and fractionated using Q-Sepharose and Sephadex G-15 columns to isolate their iron-binding peptides. Two major fractions were produced from each of the Q-Sepharose ion exchange chromatography and the Sephadex G-15 gel filtration chromatography. Among the fractions, the peptide fraction with a high iron-binding activity level, F12, was isolated. These results suggest that chicken feather protein hydrolysates can be used as iron supplements.

• The Korean Journal of Food And Nutrition
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• v.10 no.3
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• pp.382-386
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• 1997

In the present study, an attempt was made to investigate the effects of steeping treatment on browning of onion hydrolysate. After steeping treatment with solvents, phenols content of methanol and ethanol were showed 25.1mg/ml and 24.9mg/ml. And absorbance of methanol and ethanol was showed 0.26 and 0.22. L and b value of treatment with methanol and ethanol were lower than other solvents. Browning reaction of onion hydrolysate was decreased with increasing concentration of ethanol. Treatment of above 80% ethanol was effective to remove phenols and was showed a low color intensity. Treatment with 80% ethanol was more effective than addition of cystein to remove phenols and to decrease browing degree.

• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.133-141
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• 1983

The kinetics of the acid-catalyzed hydrolysis of a series of 1-aryl-2-pyrrylideneaniline (3) have been studied in 20% MeOH solution using UV spectrophotometer. Substituents in 3 showed a relatively small effect, with hydrolysis facilitated by electron withdrawing group. By obtaing linear plots of $log k_{obs}$ against Hammett ${\sigma}$ constants, it was able to show that substituents had a considerable contribution to the aromaticity of pyrrole compounds. The small positive ${\rho}$ values were consistent with the rate-determining addition of water to the protonated schiff base in the buffer solution of pH 4 to 8, whereas the addition of water to the free imine seemed to be the rate-determining in the solution of acidities greater than pH 8.

• Food Science and Preservation
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• v.31 no.3
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• pp.444-451
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• 2024

This study aimed to investigate the characteristics of protein hydrolysates derived from defatted egg yolk using various proteolytic enzymes and compare the antioxidant activity of the resulting hydrolysates. The defatted egg yolk powder was subjected to enzymatic hydrolysis using four different proteases (alcalase, bromelain, flavourzyme and neutrase), and the resulting hydrolysates were evaluated for their antioxidant properties. Through analysis of available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was observed that the defatted egg yolk powder treated with alcalase, flavourzyme, and neutrase for 12 h exhibited a high degree of hydrolysis value. Based on the RC₅₀ values obtained from two different antioxidant analyses, all hydrolysates showed comparable antioxidant activity, except for the alcalase hydrolysate, which demonstrated notably higher scavenging activity against hydrogen peroxide than the other hydrolysates. These findings suggest the potential of protein hydrolysates from defatted egg yolk, a by-product of lecithin extraction, as natural antioxidants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.246-255
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• 1996

To develop a natural antioxidative peptide, the gelatin was extracted from fish (Yellowfin sole) skin by hot $water(50^{\circ}C)$ extraction method and hydrolyzed with Alcalase, pronase and collagenase through a continuous 3-step membrane reactor. Each step enzymatic hydrolysates were determined the antioxidative activity and their synergistic effects, compared with $\alpha-tocopherol$ and butylated hydroxytoluene (BHT). Also, we tried to investigate the antioxidative disposition of peptide which was successfully separated by gel filtration, ion-exchange chromatography, and HPIC in cultured rat hepatocytes intoxicated with tert-butyl hydroperoxide (TBHP). Second step enzymatic hydrolysate (SSEH) among all hydrolysates and $\alpha-tocoperol$ was showed the strongest antioxidative activity. The optimum concentration of antioxidative activity for SSEH was $1\%(w/w)$ in linoleic acid. The synergistic effects were increased in using the hydrolysate with tocopherol and BHT. In the presence of the peptide isolated from SSEH, supplemented hepatocytes exposed to TBHP showed that delayed cell killing and decreased significantly the lipid peroxidation, compared with hepatocytes not cultured with isolated peptide.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.141-148
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• 2012

In order to study the utilization of brown seaweed Laminaria japonica as an alternative renewable feedstock for bioethanol production, the properties of acid hydrolysis and ethanol fermentation were investigated. The acid hydrolysis enhanced the final yield of fermentable sugars, which led great increase of ethanol productivity. The maximum yield of reducing sugars reached 135 mg/g-dry Laminaria japonica after 1.0N sulfuric acid-hydrolysis at $130^{\circ}C$ for 6 h. The Saccharomyces cerevisiae (ATCC 24858) could ferment $C_6$-sugars like glucose, galactose and mannose into ethanol, but not $C_5$-sugars like arabinose and xylose. Optimal fermentation time varied with sugars; 48 h for glucose, 72 h for galactose, and 96 h for mannose. Nevertheless, the ethanol yield from the hydrolysate reached 242 mg/g-dry Laminaria japonica after fermentation by the S. cerevisiae at $35^{\circ}C$ for 96 h, which corresponds to approximately 4 times more than the theoretical yield from total reducing sugars in the hydrolysates. It indicates that the non-reducing sugars or oligosaccharides dissolved in the hydrolysate played an important role in producing bioethanol. The ethanol concentration linearly increased from 2.4 to 9.2 g/L, while the ethanol yield per dry weight of biomass decreased from 242 to 185 mg/g, with increasing the ratio of biomass to acid solution from 1 to 5% (w/v). The bioethanol yield estimated was approximately 7,400~9,600 kg/ha/year, and indicated that Laminaria japonica is a promissing feedstock for bioethanol production.