• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.39-45
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• 1993

The effects of enzymatic modification with pepsin and actinidin was studied on molecular weight distributions and functional properties of hydrolysates from soy protein isolate (SPI) differing in degree of hydrolysis. The hydrolyzed SPI by pepsin showed 41.5% degree of hydrolysis after 5 min, and maximum hydrolysis was obtained after 2 hours. Actinidin hydrolyzed SPI 26.71% degree after 1 hour. On SDS-PAGE, native SPI showed 9 distinguishable bands on SDS-PAGE gel. Pepsin treated SPI showed one broad band in the lower part of gel. This band was shifted further to the bottom of the gel and became faint as hydrolysis time increased. While actinidin treated SPI showed different SDS-PAGE pattern from pepsin. However PAGE patterns were similar with pepsin and actinidin treated groups. With pepsin treatment, solubility of SPI distinctively increased around isoelectric point(pI). Emulsifying activity (EA) and emulsifying stability (ES) showed marked increase over pH range of $3.0{\sim}8.0$. 5 min modified group had most excellent foam expansion (FE). Foam stability (FS) was increased as pepsin treatment time increased at pI. With actinidin treatment, solubility was increased. 60 min modified SPI had the most effective EA at pH 4.5. However ES was not effected by actinidin treatment. 5 min modified group was most effect in FE. FS was higher at alkaline pH.

• Food Science and Preservation
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• v.17 no.1
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• pp.91-99
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• 2010

Extraction and bleaching of citric acid- and pepsin-soluble collagens (ASC and PSC, respectively) from shark (Isurus oxyrinchus) skin and muscle were investigated. The optimal sodium hydroxide concentration for extraction was 0.3 M and the optimal treatment time for removal of foreign material was 9 h. The optimal sodium hypochlorite level for bleaching of shark skin was 0.48% (w/v), and sodium hypochlorite was a better bleaching agent than acetone, hydrogen peroxide (10%, v/v), sodium sulfite (0.48%, w/v), sodium thiosulfate (0.48%, w/v), or sodium metabisulfite (0.48%, w/v). Optimal citric acid concentration and extraction time for ASC were 0.3 M and 72 h, respectively, whereas optimal conditions for extraction of PSC were treatment with 0.1 M citric acid containing 0.1% (w/v) pepsin for 24 h. Protein contents in ASSC (acid-soluble shark skin collagen), ASMC (acid-soluble shark meat collagen), PSSC (pepsin-soluble shark skin collagen), and PSMC (pepsin-soluble shark meat collagen) were 88.66%, 83.09%, 90.33%, and 84.81% (on a dry weight basis), respectively, similar to that of commercial marine collagen (88.86%). Net collagen contents of ASSC, ASMC, PSSC, and PSMC, calculated from hydroxyproline levels, were 70.31%, 25.70%, 83.09%, and 32.94%, respectively. The yields of freeze-dried ASSC, ASMC, PSSC,and PSMC were 57.22%, 53.85%, 23.28%, and 20.61%.

• Food Science of Animal Resources
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• v.18 no.2
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• pp.157-163
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• 1998

This study was carried out to examine that pepsin-hydrolyzed bovine lactoferrin has applicabilities which are market milk and dairy products. The stability of pepsin-hydrolyzed bovine apo-lactoferrin and the change of its antibacterial character has been studied under various method for pasteurization (LTLT; 65$^{\circ}C$ / 30min., HTST ; 75$^{\circ}C$ / 15sec., UHT ; 135$^{\circ}C$ / 3sec.) and pH Values (pH 2.0, pH 4.0, pH 6.8). The ehated samples were assayed for minimal bacteriocidal concentrations (MBCs) and bacteriocidal effect against E. coli. The results obtained were summarized as follows: After fractionation of pepsin-hydrolyzed bovine lactofeerin by gel filtration. several peptide fractions were found that had strong antibacterial activity. SDS-PAGE showed that the one of these fractions with strong antibacterial activity, which had a molecular mass a range of 30∼33KDa. The MBCs for pepsin-hydrolyzed bovine lactoferrin fraction No. 2 against E. coli required to cause complete inhibition of growth varied within the range of 200∼400 $\mu\textrm{g}$/ml, depending on heat treatments and pH conditions. The peptide fraction No. 2 showed strong bacteriocidal activity against E. coli at LTLT and HTST treatments under acidic pH conditions. and was reduced activity at UHT treatment under pH 6.8 condition.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.851-856
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• 2005

The aim of this experiment was to evaluate the stability of anti-Helicobacter pylori IgY in water soluble fraction(WSF) of egg yolk according to the heat, pH and digestive enzyme treatment. Anti-H. pylori IgY content of WSF remained 76% after pasteurization(63$^{\circ}C$ for 30 min). The stability of anti-H. pylori IgY at different pH showed a tendency to diminish according to decreasing pH from 7.0 to 1.5(p＜0.05). Anti-H. pylori IgY content was 84.4% after treatment for 1 hour at 37$^{\circ}C$ in pH 5.0. There were significantly differences in IgY content between 1 hour and 2 hours at pH 2.0 in 200 units of pepsin treatment(p＜0.05). However, IgY was relatively stable at pH 4.0 regardless of the reaction time and the concentration of pepsin. The stability of IgY of egg yolk after the treatment of trypsin was significantly higher than that of water soluble fraction (p＜0.05). This results indicated that anti-H. pylori IgY showed relatively a good stability on heat, pH and digestive enzyme.

• Journal of Dairy Science and Biotechnology
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• v.14 no.2
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• pp.135-146
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• 1996

This experiment was carried out to investigate the changes of casein of cheese base treated with substitute enzyme during ripening. The cheese base without enzyme treatment(control, D)and cheese base treated with only calf rennet(A), cheese base treated with mixed enzyme(calf rennet :porcine pepsin 1:1, B), cheese base treated with only porcine pepsin(C) were manufactured. The changes of casein were analyzed by means of HPLC and electrophoresis as experimental parameters during ripening. Gel filtration(HPLC) of casein by Superose 12 column in Cheddar cheese showed 5 fractions immediately after manufacturing and 8 fractions after six months ripening. Though D showed no difference in number of fraction(4 fraction) during 8 weeks ripening, A, B, C have represented the change of fraction number 4 to 5, 4 to 7, 4 to 8, respectively. As the mixing ratio of porcine pepsin increased, higher degradability of casein appeared. After 8 weeks ripening, electrophoresis of casein in cheese base showed three bands as an ${\alpha}$$_{s1}$casein from A and five bands from B, C. In case of D one major band and two minor bands were appeared as an ${\alpha}$$_{s1}$-casein. As the additional level of porcine pepsin increased the concentration of ${\beta}$-casein band decreased. however, that of ${\gamma}_1$ ${\gamma}_2$-casein band increased and para-${\kappa}$-casein band appeared from A, B, C, except D.

• Nutrition Research and Practice
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• v.7 no.1
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• pp.3-8
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• 2013

Buckwheat is known as a health food but is one of the major food allergens triggering potentially fatal anaphylaxis in Asia, especially in Japan and Korea. This study was conducted to investigate the characteristic of enzymatic resistance of buckwheat protein and allergenic potential. Enzymatic resistance of buckwheat protein was performed with in vitro digestibility test in simulated gastric fluid (SGF), pH 1.2, using pepsin and simulated intestinal fluid (SIF) using chymotrypsin. Reactivity of buckwheat proteins to human IgE was performed using six allergic patients sensitized to buckwheat. Buckwheat's IgE levels were measured using the Phadia UniCAP-system. Buckwheat protein, 16 kDa, still remained after 30 min treatment of pepsin on SDS-PAGE. Even though 16 kDa almost disappeared after 60 min treatment, two out of the six buckwheat patients' sera showed reactivity to hydrolysate after 60 min treatment, indicating that allergenicity still remained. In simulated intestinal fluid (SIF) using chymotrypsin, buckwheat protein, 24 kDa, showed resistance to hydrolysis with chymotrypsin on SDS-PAGE, and still had allergenicity based on the result of ELISA. Our results suggest that buckwheat proteins have strong resistance to enzyme degradation. This may be attributed in part to the allergenic potential of buckwheat. Further study should be continued regarding buckwheat allergy.

• Food Science of Animal Resources
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• v.34 no.2
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• pp.151-157
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• 2014

This study investigated the effects of three proteases (trypsin, pepsin and chymotrypsin) on the hydrolysis efficiency of porcine placenta and the molecular weight (Mw) distributions of the placental hydrolysates. Because placenta was made up of insoluble collagen, the placenta was gelatinized by applying thermal treatment at $90^{\circ}C$ for 1 h and used as the sample. The placental hydrolyzing activities of the enzymes at varying concentrations and incubation times were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel permeation chromatography (GPC). Based on the SDS-PAGE, the best placental hydrolysis efficiency was observed in trypsin treatments where all peptide bands disappeared after 1 h of incubation as compared to 6 h of chymotrypsin. Pepsin hardly hydrolyzed the placenta as compared to the other two enzymes. The Mw distribution revealed that the trypsin produced placental peptides with Mw of 106 and 500 Da. Peptides produced by chymotrypsin exhibited broad ranges of Mw distribution (1-20 kDa), while the pepsin treatment showed Mw greater than 7 kDa. For comparisons of pre-treatments, the subcritical water processing (37.5 MPa and $200^{\circ}C$) of raw placenta improved the efficiency of tryptic digestions to a greater level than that of a preheating treatment ($90^{\circ}C$ for 1 h). Consequently, subcritical water processing followed by enzymatic digestions has the potential of an advanced collagen hydrolysis technique.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.433-441
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• 1995

A series of experiments was conducted to determine the influence of various pepsin-HCL pretreatment factor, hereby the factors of duration of washing for the retrieved bags, inherent to the mobile nylon bag technique (MNBT), on apparent ileal digestibility of crude protein (AIDCP) and apparent ileal digestibility of dry matter (AIDDM). At last, the AIDCP and apparent ileal digestibility of amino acids (AIDAA) in maize, barley, wheat, rapeseed meal, cottonseed meal and three mixed diets were determined with the MNBT and ileo-rectal anastomis pigs (IRAT). For the MNBT techniques, bag measuring $25{\times}40$ MM and containing 0.75 g feedstuff samples, after pre-digestion in vitro, were introduced into the ileo-rectal anastomis pigs (IRAT) gastrointestinal tract through a duodenal cannula and recovered in the ileal digesta between 6 and 12 h. later. 1. The apparent ileal digestibility of dry matter (AIDDM) and crude protein (AIDCP) of the tested samples, with the exception of fish meal, determined by MNBT were not affected by the different pepsin-HCL pretreatment times in vitro between 2.5 h. and 4 h. 2. There was no significant (p > 0.05) difference of the AIDCP and AIDDM of maize determined by the MNBT among different pepsin concentration (0.03%, 0.07% and 0.1 %) treatment in vitro. 3. The AIDCP determined with the MNBT was affected by the washed and unwashed recovered bags from the ileal digesta. 4. The AIDCP and AID amino acids (AIDAA) of maize, barley, wheat, rapeseed meal, soya-bean meal, cottonseed meal and three mixed diets from the MNBT, with a solution of 0.01N HCL (PH 2) and 0.1% of pepsin concentration, a pepsin-HCL pretreatment time in vitro or 4h. and a washing time of the recovered bag from the ileal digesta compared well with those from the IRAT. The linear regression analysis showed a significant correlation (p < 0.01) of AIDCP and AIDDA between the IRAT and MNBT.

• Food Science of Animal Resources
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• v.33 no.4
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• pp.493-500
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• 2013

Gelatin is a collagen-containing thermohydrolytic substance commonly incorporated in cosmetic and pharmaceutical products. This study investigated the antioxidant activity of gelatin by using different reagents, such as 2,2-azinobis-(3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS), 2,2-di (4-tert-octylphenyl)-1-picrylhydrazyl (DPPH), and oxygen radical absorbance capacity-fluorescein (ORAC-FL) in a porcine gelatin hydrolysate obtained using gastrointestinal enzymes. Electrophoretic analysis of the gelatin hydrolysis products showed extensive degradation by pepsin and pancreatin, resulting in an increase in the peptide concentration (12.1 mg/mL). Antioxidant activity, as measured by ABTS, exhibited the highest values after 48-h incubation with pancreatin treatment after pepsin digestion. Similar effects were observed at 48 h incubation, that is, 61.5% for the DPPH assay and 69.3% for the ABTS assay. However, the gallic acid equivalent (GE) at 48 h was $87.8{\mu}M$, whereas $14.5{\mu}M$ GE was obtained using the ABTS and DPPH assays, indicating about sixfold increase. In the ORACFL assay, antioxidant activity corresponding to $45.7{\mu}M$ of trolox equivalent was found in the gelatin hydrolysate after 24 h hydrolysis with pancreatin treatment after pepsin digestion, whereas this activity decreased at 48 h. These antioxidant assay results showed that digestion of gelatin by gastrointestinal enzymes prevents oxidative damage.

• Korean Journal of Veterinary Research
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• v.15 no.2
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• pp.223-231
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• 1975

In mammals there are two distinct cellular units of the gastric glands which are responsible for the secretion of acid and pepsin respectively, namely, the parietal cells for acid and the peptic or chief cells for pepsin. On the other hand, the bird does net have separate parietal and chief cells in the glandular stomach. There exist only a single cell type in the asian gastric secretory-glands. In spite of this single cell type, however, variation in pepsin and acid secretion can he seen. Present study was conducted to know distribution, secretion and formation of the pepsinogen granules in chicken and rat stomach which observing by light and electron microscope. 1. In chicken, the pepsinogen granules are distributed in all submucosal gland cells and yet there are no distinction of parietal and chief cells. In rat, the pepsinogen granules are distributed in chief cells which lined the lower two-thirds of the gastric tubles and the parietal cells occupy upper third of the tuble. 2. Carbachol markedly stimulates the secretion of pepsinogen granules in chiken and rat, but Histamine is slightly. 3. After Histamine and Carbachol treatment, the pepsinogen granules are formated continuously and reaccmulated as control after 3 to 4 hours.