• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.417-426
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• 1997

Rice bran protein hydrolysates were prepared and some of their physicochemical properties were investigated to utilize rice bran as starting material for functional food ingredient. Rice bran proteins (RBP) were prepared from defatted rice bran by alkaline extraction and isoelectric precipitation. The enzyme for hydrolysis of RBP was selected through measuring relative activity by pH-drop method and comparing the degree of hydrolysis (DH) of hydrolysates. The enzymatic hydrolysates prepared by $Esperase^{\circledR}$ treatment were partitioned into two fractions by ultrafiltration(UF) with a 10 kDa molecular weight cut-off membrane. Each fraction was applied to a cholic acid-conjugated ${\omega}-aminohexyl$ Sepharose 4B column and the bile acid-binding components were obtained by eluting with deoxycholate. Gel permeation chromatography on a Sephadex G-50 column revealed that molecular weight of the bile acid-binding fraction of UF permeate was distributed in ranges of $2\;kDa{\sim}10\;kDa$ and $0.2\;kDa{\sim}0.6\;kDa$. Three peaks (R-1, R-2 and R-3) were obtained by prep-HPLC of bile acid-binding fraction of UF retentate and analyzed for total and free amino acid composition. The results showed that proline content of the bile-acid binding polypeptides and peptides was four times as much as that of rice bran protein and that the peak corresponding to higher average hydrophobicity had a higher free amino acid content. Average hydrophobicity slightly increased with enzymatic hydrolysis.

• Food Science and Preservation
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• v.15 no.6
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• pp.903-908
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• 2008

This study investigated protein changes in soymilk and whole soymilk due to enzymatic hydrolysis. The total free amino acid contents of low molecular weight soymilk (LSM) and low molecular weight whole soymilk (LWSM) were higher than soymilk (SM) and whole soymilk (WSM). The essential amino acid content was similar in SM and LSM, but was higher in LWSM than WSM. In SDS-PAGE performed to tendency of becoming low molecules, the soy protein molecular weights were 3372 kDa for SM and WSM, but 17 kDa or less for LSM and LWSM. Also, high molecular weight protein spots were evident in 2-D electrophoresis of SM and LSM, but only low molecular weight protein spots of various sizes were evident in WSM and LWSM. This suggests that the high molecular weight protein in SM and WSM is changed to low molecular weight protein by enzymatic hydrolysis. Further investigations of the separation and qualities of these proteins are required.

• Journal of Applied Biological Chemistry
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• v.55 no.4
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• pp.263-266
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• 2012

Isolation of iron and calcium-binding peptides derived from cottonseed meal protein (CMP) hydrolysates was investigated. The degree of hydrolysis of CMP by Flavourzyme was monitored using trinitrobenzenesulfonic acid method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Enzymatic hydrolysis of CMP for 12 h was sufficient for the preparation of CMP hydrolysates, and the hydrolysates were membrane-filtered under 3 kDa as a molecular weight. The filtered solution was fractionated using Q-Sepharose fast flow, Sephadex G-15, and reversed phase-high performance liquid chromatography for iron and calcium-binding peptides. As a result, F51 fraction was obtained as the best candidate for calcium and iron chelation, and the isolated iron and calcium-binding peptides can be used as functional food additives, similar to iron and calcium supplements.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.131-136
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• 2002

Protease activity in matured wax gourd sarcocarp was 0.19unit/0.5ml, immatured wax gourd sarcocarp 0.56unit, and matured wax gourd 24.35 unit, immatured wax gourd core 0.35unit. Protease activity in matured wax gourd sarcocarp to raw meat or raw pork was 13,0 unit, 7.4 unit, respectively, and that in wax gourd core to raw beef was 30.2 unit, and raw pork was 24.5 unit. Thermal stability of pretense in matured wax gourd sarcocarp was stable below 70$\^{C}$ when it was heated for 10 minutes. In case of 80$\^{C}$, the remaining activity was 21%, and at 90$\^{C}$, it was lost entirely. The absorption spectrum showed peak at 280nm. According to the HPLC analysis, casein was hydrolyzed into small size by protease in core or sarcocarp of matured was gourd and immatured wax gourd. Wax gourd diluted by 1/10 showed two peaks, one was from casein being hydrolyzed, and the other was from the increased molecular weight with coagulated casein. On the other hand, the molecular weight didin't increase in immatured wax gourd core diluted by 1/10. The result of dilution of 1/10 showed different pattern from undiluted one, but the peak of sarcocarp in matured wax gourd was 1 and the peak of core in immatured wax gourd was 5, and those of core and sarcocarp of immatured wax gourd were 3 respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.842-849
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• 1997

This study was designed to investigate the antioxidative activity of enzymatic hydrolysates prepared from defatted anchor muscle by various pretenses. In these hydrolysates, the hydrolysates derived from pepsin and Protamex showed the strongest antioxidative activity. Enzymatic hydrolysates also showed the synergistic effects on antioxidative activity of $\alpha-tocopherol$, and almost no change in butylated hydroxytoluene (BHT). Peroxidation of metal ions $(Fe^{3+},\;Cu^{2+})$ was inhibited by enzymatic hydrolysates. Ten fractions (P-1 to P-10) were fractionated from the peptic hydrolysates by Amberlite IR-120 and Bio-gel P-2 column chromatography. The maximum antioxidative activity was observed in the traction P-2 (fraction No. $26\~31$). In amino acid composition of before and after hydrolysis of defatted anchovy muscle and the active fractions (P-2), contents of aspartic arid and glutamic acid were increased, but alanine, cysteine, tyrosine and phenylalanine were decreased.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.133-134
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• 2001

발효식품에 함유되어 있는 저분자 peptide는 발효 동안이나 가수분해되는 과정에서 생산된다. 이렇게 생성된 저분자 peptide는 생물학적 활성이 크다고 보고되고 있다. 생리기능성 펩티드의 종류를 살펴보면, 동물성 유래의 호르몬류나 식물성 유래의 효소 저해물질 등 활성형으로 존재하는 현재적(顯注的) 생리 활성 peptide, 소화과정이나 식품가공 과정에서 부분 가수 분해에 의해 불활성형 단백질로부터 파생되는 잠재적 생리활성 peptide, cyclo (His-Pro) 등과 같은 가수분해 이외의 기구에 의해 생성되는 생리활성 펩타이드 등이 있다. (중략)

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.136-140
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• 2008

In order to utilize the silkworm larvae (Bombyx mori) protein, defatted silkworm protein was hydrolysed by four enzymes (pepsin, trypsin, neutrase and alcalase) at various hydrolysis times (6, 12, 18, 24 and 30 hr) and suspension concentrations (2, 5, 10, 15 and 20%). Protein solubility index, ACE (angiotensin converting enzyme) inhibitory activity and antioxidative activity of silkworm protein hydrolysates were investigated. The optimum condition of hydrolysis was 10% suspension concentration and 18 hr. Protein solubility index of trypsin treatment was higher than other enzyme treatments. ACE inhibitory activity and $IC_{50}$ value of antioxidative activity of neutrase treatment were 86.16% at $100\;{\mu}g/mL$ and $352.75\;{\mu}g/mL$, respectively; also, these values were higher than other enzyme treatments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.282-292
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• 1987

In order to exploit a new type of food source, enzamatically modified hydrolysates and the plasteins synthesized from the filefish (Nevoden modestus) protein hydrolysates by plastein reaction were investigated. The optimum conditions for enzymatic hydrolysis of filefish muscle and synthesis of plasteins using papain, pepsin, $\alpha-chymotrypsin$ and protease (from Streptomyces griceus) were determined. The optimum temperature and pH for the hydrolysis of filefish muscle by papain, pepsin, $\alpha-chymotrypsin$ and protease were $50^{\circ}C,\;40^{\circ}C,\;55^{\circ}C\;and\;50^{\circ}C$; and 6, 2, 7 and 8, respectively. Those for incubation time and enzyme concentration were 4hr, $0.5\%$ for papain and protease, 24hrs $1.0\%$ for pepsin and $\alpha-chymotrypsin$. The pepsin was found to be more reasonable substrate for plastein synthesis from the economic point of view. The enzyme-induced plastein reaction could be optimized, namely, pH 4 for pepsin, pH 7 for $\alpha-chymotrypsin$, pH 6 for papain and protease: substrate concentration $40\%$ for pepsin, $\alpha-chymotrypsin$ and protease, $50\%$ for papain; the time of incubation, 24hr; enzyme/substrate ratio, 1 : 100(W/V) ; incubation temperature, $50^{\circ}C$.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.273-279
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• 1993

Hydrolytic patterns of 11S globulin (glycinin), storage protein of soybean, by soymilk-clotting enzymes Iand IIfrom Bacillus sp. K-295G-7, which was the first soymilk-clotting enzyme to be found in a bacteria, was investigated. The clotting time of about 4~5 min is revealed by the Enzymes Iand II(0.025 units at 35$^{\circ}C$) on the acidic subunit. In electrophoresis, acidic subunit (A$_3$, M.W. 45,000) disappeared almost completely within 2 min and new products corresponding to the molecular weight of 16,000 and 20,000 were formed by the action of Enzymes I and II. Furthermore, Enzyme II produced a degradation compound having a molecular weight of about 30,000. In contrast, the hydrolytic patterns of basic subunit (M.W. 20,000) by Enzymes I and II were similar, but Enzyme II produced low molecular weight products slower than that of Enzyme I.