• Journal of Nutrition and Health
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• v.26 no.5
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• pp.585-592
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• 1993

In order to investigate the hypocholesteremic effect of soybean perptides, soybean protein(ISP), casein(CNP), their peptic hydrolyzates fractionated by acid precipitation at different pH's(SHT, SH8, SH6, SH4, CHT, CH5, CH4) and amino acid mixtures of the same composition as the proteins(SAA, CAA) were fed to rats and the concentration of serum cholesterol was measured. Then in vitro digestibility and molecular weight distribution of the peptides by pepticpancreatic hydrolysis was measured by FPLC. The lower the in vitro digestibility of peptides is, the lower the concentration of serum cholesterol becomes(r=0.986) and the higher the ratio of macropeptides is, the lower the concentration of serum cholesterol becomes(r=-0.932) in rats. These results suggest that the in vitro digestibility of peptides has close relationship to the concentration of serum cholesterol in rats and non-digestible meacropeptides or polypeptides especially more than 1 kDa, formed through digestion in gut, may lower the serum cholesterol in rats.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.571-575
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• 1993

Effect of surface hydrophobicity of soybean peptides on serum cholesterol in rats was investigated. Soybean protein(ISP), casein(CNP), and their peptic hydrolyzates fractionated by acid precipitations (SHT, SH8, SH6, SH4, CHT, CH6, CH5, CH4) were fed to rats and the concentration of serum cholesterol and the fecal steroid excretion were measured. And surface hydrophobicities of the peptide fractions were measured by determining by the ANS flourescence intensity and SDS binding capacity. It was found that the higher the surface hydrophobicity of peptides was, the more the fecal steroids excreted(r=0.801) and the lower the concentration of serum cholesterol became(r=-0.868). However, there was no relationship between SDS surface hydrophobicity and fecal steroids or serum cholesterol. ANS surface hydrophobicity of soybean protein was increased by enzymatic hydrolysis. These results suggest that high surface hydrophobicity of peptides formed during digestion is responsible for the hypocholestrolemic effect of soybean protein through the hydrophobic interaction between the peptides and bile salts in rats.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.698-703
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• 2006

We investigated how the addition of polypeptides to instant fried noodle dough affects the dough properties, starch gelatinization, and textural properties of cup-type instant fried noodles. After comparing farinograph results of 100% wheat flour with 1% wheat flour substituted with gluten, there was a small difference in the mechanical dough properties. However, in the case of 1% wheat flour substituted with gluten peptides, the dough development time increased, dough stability decreased, and weakness increased. On the other hand, when gluten or gluten peptides were added, starch gelatinization did not change significantly. At the steaming stage, substitution with gluten peptides or soybean peptides markedly changed the molecular weight distributions of extractable polypeptides. Especially in the case of wheat flour substituted with 1% gluten peptides, the relative portion of low Mw extractable polypeptides (2.5-50 kDa) decreased more compared to a control. Also, the hardness and chewiness decreased in cooked cup-type instant fried noodles containing gluten peptides. This suggests that the addition of gluten peptides can reduce the rehydration time of cup-type instant fried noodles.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1277-1280
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• 2004

The effect of duodenal infusion with feed oligo-peptide solution on portal absorption of amino acids was investigated in poultry under unanaesthetized conditions. Four peptide solutions were used in the experiment: enzymatic hydrolysates from fish meal, soybean meal, cottonseed meal and rapeseed meal proteins with average molecular weights less than 3,000 Da and 1,000 Da, respectively. Intestinal absorptions of these oligo-peptide solutions were compared by determining the concentration of free amino acid (FAA) in portal blood after the duodenal administrations of oligo-peptide solutions. Absorptive intensity and balance were used to estimate the intestinal absorption rate of amino acids. The absorptive intensities of amino acids were highest for the fish and soybean meal oligo-peptides. The ratios of amino acids absorbed in the portal blood from fish and soybean meal oligo-peptides were more similar to the composition of the infused amino acids than that observed from the cottonseed and rapeseed meal oligo-peptides. A positive correlation was found between absorption rate and proportion of PAA in the oligo-peptides. The higher absorption rate could be contributed to the higher proportion of peptide bound amino acids (PAA). The results suggest that fish and soybean meal protein are significantly more easily hydrolyzed into oligo-peptides (p<0.05) in the gastrointestinal tracts of poultry and as such can be utilized more effectively by body tissues.

• Biomedical Science Letters
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• v.21 no.2
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• pp.77-83
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• 2015

Soy proteins have been extensively studied because of its multiple health benefits. However, the effects of soy proteins on human cervical cancer cells are still unclear. Therefore, this study investigated the effects of soy proteins on HeLa cells and human fibroblasts by using soybean peptides (SPs). SPs selectively increased the generation of reactive oxygen species and apoptosis in HeLa cells but not in fibroblasts. In addition, SPs suppressed the migration of HeLa cells. Although the molecular mechanisms underlying the effects of SPs on human cervical cancer cells need to be investigated further, our findings provide insights on the therapeutic effects of soy protein on cervical cancer.

• The Korean Journal of Food And Nutrition
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• v.4 no.2
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• pp.161-166
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• 1991

The blocked N-terminus and N-terminal sequence of soybean B-amylase were aetermined by analyzing the acidic peptides derived on peptic digestion of the enzyme. The acidic peptides were separated from the digest on a Dowex 50$\times$2 column(1X5cm) and purified by reversed phase-high performance liquid chromatography(RP-HPLC). The major acidic peptide, PEP-1, was a heptapeptlde. The N-terminal 7 amino acid sequence of soybean B-amylase was deduced to be acetyl-Ala-Thf-Ser-Asp-Ser-Asn-Met- from the results of sequence analysis of PEP-1 and amino acid analysis of other acidic peptides.

• Applied Biological Chemistry
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• v.6
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• pp.79-87
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• 1965

The contents of insoluble protein nitrogen, water soluble protein nitrogen anti peptides' nitrogen were determined of the samples which were taken in seven and half hours intervals during soybean-koji preparation to study changes of soybean protein, and the contents of total nitrogen and amino nitrogen were measured for the fractions resulting from molecular sieving by using Dowex 50 having various cross linkages for the peptides from soybean-koji extracts. As the results of the studies, The followings were obtained: 1. The contents of insoluble protein nitrogen and peptides' nitrogen are fairy constant at the earlier stage, where the former decreased and the latter increased markedly as mycelia grow, then rate of the decreases and the increases of them become lower at later stage after sporulation. The contents of water soluble protein are also constant at the earlier stage until covering of mycelia over the koji and increased since then until the stage of sporulation and then decreased at the later stage. 2. The amount of peptides nitrogen in each fraction obtained by the molecular sieving was almost constant at the earlier stage and the values in fractions of X-16, X-12, X-8. X-4 and X-2 increased considerably together as mycelia grow. Then the values in the fractions showed almost plateaux, after sporulalion, where the effluent fraction showed markedly increased values throughout mycelia growth.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.552-557
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• 1993

Effects of amino acid composition and average hydrophobicity of soybean peptides on serum cholesterol in rats were investigated. Soybean protein(ISP), casein(SCN), their peptic hydrolyzates fractionated by acid precipitations(SHT, SH8, SH6, SH4, CHT), and amino acid mixtures of the same composition as the proteins(SAA, CAA) were prepared to feed to rats. The amino acid composition of the peptides was analyzed by HPLC and the concentration of serum cholesterol in the rats was measured. By data analysis, it was found that there was no relationship between ratio of Lys/Arg or molar ratio of hydrophobic amino acids and serum cholesterol level. And also there was no relationship between the concentration and average hydrophobicity calculated by the method of Tanford, Manavalan, for Meirovitch, only except by the method of Krigbaum(r=-0.736); the higher the average hydrophobicity of Krigbaum was, the lower the concentration of serum cholestrol became.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.349-360
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• 2011

The objectives of present study were to characterize the peptides which were isolated from Korean fermented soybean paste, chungkukjang, and to determine their antioxidant activities. Four fractions were collected from the methanol extract of chungkukjang by using a recycling preparative HPLC. Among fractions, Fr-2 was identified to be highly potent free radical scavenging activity in the assay of 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and nitroblue tetrazolium(NBT)-reduction inhibition. Base on antioxidant effects, fraction Fr-2 was employed for the refraction with a prep-column and separated into five fractions of which two fractions were identified to have higher antioxidant activity. To confirm the amino acid constituents of antioxidant fractions Fr-2-2 and Fr-2-3 were analyzed, and eight kinds of amino acids such as aspartic acid, threonine, serine, glutamic acid, glycine, lysine, histidine, and arginine were identified as the constituent amino acids. Antioxidant activities of the separated peptides were further assessed cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl terazolium bromide (MTT), and fluorescence-activated cell sorting (FACS) analysis of H4IIE cells treated with hydrogen peroxide (H2O2). Chungkukjang peptides have shown their ability to protect H4IIE rat hepatoma cells against H2O2- induced oxidative stress by concentration and time-dependent manner. Therefore, These results indicated that fermented soybean paste chungkukjang will be promoted the antioxidant and radical scavenging activities, and beneficial for health. The antioxidant peptide fractions Fr-2-2 and Fr-2-3 were denominated as P-NICS-1 and P-NICS-2, respectively. However, further studies were required to clarify their amino acid sequences and molecular properties, and physiological significances.

• Korean Journal of Food Science and Technology
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• v.17 no.4
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• pp.276-282
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• 1985

To characterize bitter peptides in fermented protein foods, peptides were extracted with 2:1 (v/v) chloroform-methand from various samples and separated into fractions I, II, and III by Sephadex G-25 gel chromatography. Amino acid compositions of Mozzarella cheese, soybean paste, and each fraction from the two samples were analyzed to calculate the average hydrophobicity. All the solvent extracts of the food samples had strong bitter taste, although the original samples did not taste bitter. The yield of solvent extraction ranged from 0.08 to 62.50% of total nigrogen of food samples. The average hydrophobicity calculated from the amino acid composition of Mozzarella cheese was 1376 cal/mole, solvent extract 1,623 cal/mole, gel chromatography traction I, 1,797 cal/mole, fraction II, 2,454 cal/mole, and fraction III, 1,559 cal/mole. In the case of soybean paste, the average hydrophobicity of original sample, solvent extract, gel chromatography fraction I, II, and III wre 1,229, 1,654, 1,900,998 cal/mole, respectively. The important amino acids in bitter peptides were leucine, 2016, phenylalanine, proline, and voline.