• Journal of Animal Environmental Science
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• v.10 no.2
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• pp.119-126
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• 2004

The protein in the extracts from the skins of pineapple and kiwi and the optimal conditions to hydrolyze blood, egg and gluten meals with them were investigated. Protein analysis by SDS-polyacylamide gel electrophoresis showed one protein band with 22 kd molecular weight in the pineapple skin extract, and Hve protein bands with 27 kd, 22.5 kd, 22 kd, 19 kd, and 14.4 kd molecular weight in the kiwi skin extract. The 22 kd protein in the pineapple skin extract is assumed to be bromelain, and the 27 kd protein in the kiwi skin extract is assumed to be actinidin, both are pretense. The optimal conditions for hydrolysis of blood, egg, and gluten meals we: 6-24 hours in time, $60^{\circ}C$ in temperature, and pH 4-pH 7.

• Food Science of Animal Resources
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• v.36 no.4
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• pp.516-522
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• 2016

Goat milk is highly nutritious and is consumed in many countries, but the development of functional foods from goat milk has been slow compared to that for other types of milk. The aim of this study was to develop a goat milk protein hydrolysate (GMPH) with enhanced digestibility and better hypoallergenic properties in comparison with other protein sources such as ovalbumin and soy protein. Goat milk protein was digested with four commercial food-grade proteases (separately) under various conditions to achieve the best hydrolysis of α_s -casein and β-lactoglobulin. It was shown that treatment with alcalase (0.4%, 60℃ for 30 min) effectively degraded these two proteins, as determined by SDS-PAGE, measurement of nonprotein nitrogen content, and reverse-phase high-performance liquid chromatography. Hydrolysis with alcalase resulted in a significant decrease in β-lactoglobulin concentration (almost to nil) and a ~40% reduction in the level of α_s-casein. Quantification of histamine and TNF-α released from HMC-1 cells (human mast cell line) showed that the GMPH did not induce an allergic response when compared to the control. Hence, the GMPH may be useful for development of novel foods for infants, the elderly, and convalescent patients, to replace cow milk.

• KSBB Journal
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• v.6 no.2
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• pp.157-166
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• 1991

The structural properties of cellulose are significantly changed with the progress of hydrolysis reaction. The effects of changes on such properties of cellulosic substrate as crystallinity, amicessibility of enzyme to the active site of cellulose surface, and particle size on the kinetics of enzymatic hydrolysis have been studied. Among those physical studies, the apparent surface active site of cellulose particle was found to have the most significant effect on the hydrolysis kinetics. Based on the experimental results, the adsorption affinity of enzyme and hydrolysis rate were mainly influenced by the surface roughness of cellulose particle. The extent of accesssible active site may be expressed as the change of particle diameter. The Langmuir isotherm was proposed in terms of enzyme activity to explain the actual action of enzyme protein.

• Korean Journal of Food Science and Technology
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• v.47 no.6
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• pp.772-778
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• 2015

Hydrolysis of isolate soybean protein (ISP) using subcritical water (SCW) was conducted to study the feasibility for producing protein hydrolyzate. SCW hydrolysis of SPI suspension (5-15%) was conducted in an electrically heated batch reactor (2 L). The effects of temperature (230 to $270^{\circ}C$) and holding time (10 to 50 min) on the degree of hydrolysis (DH) and the production of amino acids were studied by surface response method. The DH was determined by derivatizing the hydrolyzates with ortho-phthalaldehyde (OPA) solution. It was confirmed that reaction temperature and holding time affected the hydrothermolysis of soybean protein. However, the holding time was less effective on amino acid yield when the temperature was higher than $230^{\circ}C$. In order to achieve optimal yields of amino acids exceeding 43%, the temperature should be within the range between 256 and $268^{\circ}C$ with holding time from 29 to 41 min, respectively. A maximum estimated amino acid yield of 43.5% was obtained at $268^{\circ}C$ for 35 min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1460-1466
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• 2016

This study was conducted to develop a savory ingredient using rice material. We made hydrolysates with ratios of rice bran and rice protein of 4:0, 3:1, 2:2, and 1:3 (w/w) using commercial enzymes, and then investigated their quality properties. At a ratio of 3:1, nitrogen degradation ratio (NDR), savory taste, and overall acceptability were the highest compared to other ratios. Rice bran and rice protein with a ratio of 3:1 were hydrolyzed for 13 days, and characteristics of the hydrolysate were investigated after 3, 5, 7, 10, and 13 days. Total nitrogen, amino nitrogen, and NDR of the hydrolysate after 10 days were higher than those of other hydrolysates. SDS-PAGE showed that the molecular weight of the hydrolysate peptide became smaller as hydrolysis time increased. Glutamic acid content was highest among all amino acids in the hydrolysate for 13 days. Amino acids related to bitter taste decreased from 5 to 13 days, whereas amino acids related to sweet taste substantially increased over time. Sensory evaluation showed that the hydrolysate after 10 days was best. These results suggest that rice bran and rice protein at a mixing ratio of 3:1 and hydrolysis for 10 days were optimal hydrolysis condition for development of natural savory ingredients.

• Korean Journal of Food Science and Technology
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• v.20 no.3
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• pp.338-343
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• 1988

Selected kinetic parameters and degree of hydrolysis(DH) were measured using commercial proteases(trypsin, alcalase and pronase) to study the affinity of these enzymes to 7S and 11S soy proteins. Electrophoretic patterns of the hydrolysates were also investigated. In general, the order of affinity between the proteins and the proteases was 11S(protein-rich fraction)and 7S PRF for unheated proteins, and 7S PRF and 11S PRF for preheated proteins. Substrate inhibition was present at a substrate concentration of 1.5% or higher when preheated protein was used as the substrate. The maximum DH values of alcalase were obtained from 7S PRF(60%) and 11S PRF(80%) at 1 hr hydrolysis, respectively. Trypsin hydrolyses did not affect 11S soy protein but the acidic subunits in contrast to alcalase and pronase hydrolyses which changed almost all subunits. Alcalase hydrolysis induced distinct changes on 2S soy protein.

• Mass Spectrometry Letters
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• v.9 no.2
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• pp.46-50
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• 2018

The effects of temperature and acetonitrile (ACN) concentration on microwave-assisted weak-acid hydrolysis of proteins were investigated. Myoglobin was hydrolyzed for 1 h using 2% formic acid and a microwave with different concentrations of ACN (0, 5, and 10%) at various temperatures (50, 60, 70, 80, 90, and $100^{\circ}C$). The numbers of peptides identified with each concentration of ACN were the same for each temperature. The greatest number of peptides (18 total) was obtained with hydrolysis at $100^{\circ}C$, and 6 of these were a result of additional removal of aspartic acid at the C-terminus. Hydrolysis at $80^{\circ}C$ resulted in 13 peptides, of which only 1 was generated by the additional removal of aspartic acid, and 12 were observed with hydrolysis at $100^{\circ}C$. Our results demonstrate that microwave-assisted weak-acid hydrolysis of proteins can be performed successfully at $80^{\circ}C$, which could be beneficial for limiting side reactions and generating larger peptide sequences.

• Archives of Pharmacal Research
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• v.2 no.2
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• pp.153-157
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• 1979

The carpophores of three Korean mushrooms, Coriolus versicolor, Pleurotus ostreatus, and Lentinus edodes were respectively extracted with hot water and the extract were dialyzed through Visking tube. They were found to contain an antinumor activity against sarcoma 180 implanted in mice. The components of these aqueous extracts were found to be polysaccharide and protein by color reactions including anthrone and Lowry-Folin tests. The hydrolysis of the polysaccharide with 3% HCI-MeOH and trimethylsilylation yielded four monosaccharides : glucose, mannose, galactose and xylose which were identified by G. L. C. After hydrolysis of protein with 6N HCL, fourteen to seventeen amino acids including aspartic and glutamic acids were detected by an amino acid analyzer.

• Food Science and Preservation
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• v.13 no.5
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• pp.563-568
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• 2006

The properties of mung bean were investigated depending on hydrolysis condition. The results showed that enzyme treatments (${\alpha}$-amylase and protease each at 0.1% (w/w)) by varying hydrolysis temperature showed better properties than non-pretense treatment (control group). The treatment with 0.08% ${\alpha}$-amylase was best for optimum hydrolysis of mung bean starch The treatment using a mixture of 0.08% (w/w) ${\alpha}$-amylase and 0.12% (w/w) protease was best for optimum hydrolysis of meg bean protein. The effects of Hydrolysis time of mung bean showed that the optimum time was 60 and 90 min and there fore the optimum time was set at 60 min. These result showed that the best hydrolysis conditions of mung bean were the treatment at $60^{\circ}C$ for 60 min using a mixture of 0.08%(w/w) ${\alpha}$-amylase and 0.12% (w/w) pretense, with the sugar level shown at $5.8^{\circ}Brix$, reducing sugar at 2,022.13 mg% and crude protein at 7,666.17 mg%.

• Food Science of Animal Resources
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• v.29 no.5
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• pp.633-639
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• 2009

The principal objective of the current study was to prepare low molecular weight peptides from milk proteins using enzymatic hydrolysis techniques, in an effort to assess the antioxidant activity of these peptides. The casein and whey proteins isolated from fresh milk were treated with several proteolytic enzymes, such as chymotrypsin, pepsin, and trypsin and the resulting low molecular weight peptides were collected by TCA precipitation. Their identity was confirmed by SDS-PAGE analysis. The hydrolysis experiments indicated that whey protein treated with chymotrypsin displayed the highest degree of protein hydrolysis. The antioxidant activity of milk protein hydrolysates was determined by measuring the ABTS-radical scavenging activity. The results of these experiments showed that hydrolysis of the milk protein was effective in increasing their antioxidant activities. Especially, the tryptic digested casein displayed the highest radical scavenging activity (80.7%). The hydrolyzed low molecular weight milk protein was isolated using an ultrafiltration membrane. The casein hydrolysate passed through a membrane with molecular weight cut-off (MWCO) of 3 kDa displayed the strongest antioxidant activity.