• Journal of Nutrition and Health
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• v.27 no.7
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• pp.699-708
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• 1994

This study aimed to verify the nutritional and curative effects of protein hydrolysate in rats with cysteamine-induced duodenal uncer. Duodenal ulcer rat model was established by intraperitoneal injections of cysteamine. Sprague-Dawley, female rats weighing approximately 200g were intraperitoneally injected twice cysteamine(13mg/100g BW) at intervals of 3h per day. This procedure was repeated 3$\times$at intervals of 3d. Animals fed on 10% casein diet for infection periods. After last injection, 4 kinds of diets(10% casein, 20% casein, 10% casein hydrolysate, 20% casein hydrolysate) were given. Gastric montility, trypsin activity in gastrointestinal content, retention rate of nitrogen, plasma total protein, albumin, amino-N, urinary urea nitrogen, creatinine and hydroxyproline were analyzed for nutritional effects of dietary nitrogen levels(10%, 20%) and sources(casein, casein hydrolysate). In duodenal ulcer rat model, there was no differences between 20% casein diet and 20% casein hydrolysate in the view of severeness of ulcer, gastric emptying rate, serum total protein, serum albumin, plasma $\alpha$-amino-N, UUN, creatinine excretion, GFR, nitrogen retention. On the other hand, rats on 10% casein hydrolysate diet group had more curative effect of the ulcer, higher plasma albumin concentration and nitrogen retention than 10% casein diet group. The casein hydrolysate diet group was lower trypsin activity in small intestinal content than the casein diet group, at both nitrogen levels(10%, 20%). The results suggest that protein hydrolysate be applied in diet therapy for the patients with gastrointestinal ulcer.

• Journal of Life Science
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• v.10 no.2
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• pp.131-139
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• 2000

Lecithin-free egg yolk protein (EYP), the by-product of lecithin extraction from egg yolk, which is denatured with an organic solvent, would normally be discarded. In this study, the denatured protein was renatured with alkali, and hydrolyzed with Alcalase in order to utilize by-product. The hydrolysate was separated through a series of ultrafiltration membranes with molecular weight cut-off (MWOO) of 10, 5 and 1 kDa, and the antioxidative activities of the hydrolysates was investigated. The 5K hydrolysate, permeate from 5 kDa membrane, showed stronger antioxidative activity than 10 K and 1 K hydrolysate which were permeated from 10 kDa and 1 kDa membrane, in a linoleic acid autoxidation system. In addition, the optimum concentration of antioxidative activity for 5 K hydrolysate was 1%, and the activity was about 37% higher as compared with α-tocopherol. The synergistic effect was also increased by using the hydrolysates with α-tocopherol.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.291-297
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• 1995

This study aimed to verify the nutritional and curative effects of protein hydroysate in rats model with gastric ulcer induced by restraint and water-immersion stress. Sprague-Dawley, famale rats weighing approximtely 200g were forced in 5$\times$5$\times$15cm plexiglas cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hours. After stress 4 kinds of diets(10% casein, 20% casein, 10% casein hydrolysate, 20% casein hydrolysate) were given for 5 days. In the gastric ulcer rats model, the growth, gastric emptying rate, trypsin activity in gastrointestinal content, plasma total protein, albumin, $\alpha$-amino-N, UUN, creatinine and hydroxyproline of the urine and nitrogen retention were analyzed for nutritional effects of dietary nitrogen levels(10%, 20%) and sources (casein, casein hydrolysate). The results were as follows ; In gastric ulcer rats model, severeness of ulcer, plasma protein, gastric emptying rate, nitrogen retention rate were not different between 20% casein-fed group and 20% casein hydrolysatefed group. But 10% casein hydrolysate-fed group had more curative group. The casein hydrolysate diet-fed group was lower trysin activity in small intestianl content than the casein-fed group, at both casein level(10%, 20%). Finally at 20% levels, there was no difference between casein and casein hydrolysate diet, but 10% level, casein hydrolysate diet was more curative of ulcer than casein diet in gastric ulcer rat model. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.

• Journal of Life Science
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• v.10 no.5
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• pp.475-483
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• 2000

Normally, aerobic cells are protected from the damage of free radicals by antioxidative enzymes such as catalase, superoxide dismutase (SOD), glutathione (GSH) peroxidase and GSH-S-transferase. In this study, we have investigate the effect of egg yolk protein hydrolysates on antioxidative activity and the activity of antioxidative enzyme in cultured hepatocytes (Chang). Without the pretreatment with hydrolysate, about 50% of the hepatocytes were killed within 2h by 225$\mu$M tert-butyl hydroperoxide (t-BHP). By contrast, fewer than 20% of the 5 K hydrolysate (permeate from 5 kDa membrane and not passed through 1 kDa membrane)-pretreated hepatocytes were killed by the same concentrations of t-BHP. In addition, the activities of catalase, GSH peroxidase and GSH-transferase were significantly increasing with the treatment of 5 K hydrolysate. These results suggest that 5 K hydrolysate exerts antioxidative effect by increasing activity of antioxidative enzymes.

• Journal of Nutrition and Health
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• v.30 no.6
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• pp.614-621
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• 1997

The experiments were performed to investigate the effects of protein and protein hydrolysates on lipid metabolism in the hyperlipidemic/hypercholesterolemic rat model induced by feeding fat-enriched diet. In Except 1 male rats were fed four semi-purified high fat and cholesterol diets that contained different nitrogen source, casein(C), casein hydrolysate(CH), corn gluten(G) and corn gluten hydrolysate(GH), for 6 weeks. In Expt. 2 rats were fed high fat and cholesterol diet for 4 weeks to induce hyperlipidemia and hypercholesterolemia. Then the rats were divided into 4 groups and were fed the four kinds of above experimental diets for 4 weeks consecutively. The contents of total lipid , cholesterol and triglyceride in blood, liver and feces were determined. Serum lipid concentrations of CH, G and GH were significantly lower than that of C. Serum cholesterol concentrations of hydrolysate groups(CH and GH) were significantly lower than those of intact protein groups(C and G). Serum HDL -cholesterol concentration tended to increase by hydrolysate intake. The total lipid, cholesterol contents in liver showed similarity results as above. Fecal lipid excretions of CH, G, and GH groups were significantly higher than that of C group. These results indicate that hypolipidemic and /or hypocholesterolemic effect of corn gluten or protein hydrolysates were detected in the process of inducing hyperlipidemia by high-fat and cholesterol diet or after inducing hyperlipidemia.

• Food Science of Animal Resources
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• v.40 no.6
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• pp.1033-1043
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• 2020

This study investigated the impacts of gelatin hydrolysate addition on the technological properties and lipid oxidation stability of cooked sausage. Gelatin hydrolysate was prepared from pork and duck skin gelatin, through stepwise hydrolysis using collagenase and pepsin. The cooked sausages were formulated without gelatin (control) or with 1% pork skin gelatin, 1% duck skin gelatin, 1% pork skin gelatin hydrolysate, and 1% duck skin gelatin hydrolysate. The pH, color characteristics, protein solubility, cooking loss, and textural properties of cooked sausages were evaluated, and the 2-thiobarbituric acid reactive substances (TBARS) value was measured weekly to determine lipid oxidation stability during 4 wk of refrigerated storage. Enzymatic hydrolysis of gelatin decreased protein content and CIE L* but increased redness and yellowness (p<0.05). When 1% gelatin or gelatin hydrolysate was incorporated in cooked sausage, however, little to no impacts on pH value, moisture content, protein content, color characteristics, protein solubility, and cooking loss were found (p>0.05). The addition of 1% duck skin gelatin hydrolysate increased the cohesiveness and chewiness of cooked sausages. The inclusion of 1% duck skin gelatin accelerated lipid oxidation of cooked sausages during refrigerated storage (p<0.05), whereas duck skin gelatin hydrolysate caused a lower TBARS value in cooked sausage compared to duck skin gelatin. The results show comparable effects of gelatin and gelatin hydrolysate addition on the technological properties of cooked sausages; however, the oxidative stability of raw materials for gelatin extraction should be evaluated clearly in further studies.

• Nutrition Research and Practice
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• v.3 no.3
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• pp.200-207
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• 2009

This study examined the effects of com gluten (CG) and its hydrolysate consumptions on weight reduction in rats fed a high-fat diet. Eight-month-old male Sprague-Dawley rats (n=40) were fed a high-fat diet (40% calorie as fat) for 4 weeks. They were then randomly divided into four groups and fed the isocaloric diets with different protein sources for 8 weeks. The protein sources were casein (control group), intact CG (CG group), CG hydrolysate A (CGHA group, 30% of protein as peptides and 70% as free amino acids) and CG hydrolysate P (CGHP group, 93% of protein as peptides and 7% as free amino acids). Body weight gain, adipose tissue weights, nitrogen balance, absorptions of energy, protein and fat, lipid profiles in plasma, liver and feces and hepatic activities of camitine palmitoyl transferase (CPT), fatty acid synthase (FAS), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH) were assessed. The CGHA diet had the highest amount of BCAAs, especially leucine, and most of them existed as free amino acid forms. The CGHA group showed significant weight reduction and negative nitrogen balance. Protein absorption and apparent protein digestibility in the CGHA group were significantly lower than those in other groups. Adipose tissue weights were the lowest in the CGHA group. Activity of CPT tended to be higher in the CGHA group than in other groups and those of FAS, ME and G6PDH were significantly lower in the CGHA group than in other groups. In conclusion, the CGHA diet which had relatively high amounts of free amino acids and BCAAs, especially leucine, had a weight reduction effect by lowering adipose tissue weight and the activities of FAS, ME and G6PDH in experimental animals, but it seemed to be a negative result induced by lowering protein absorption, increasing urinary nitrogen excretion and protein catabolism.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.26-35
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• 2017

The hydrolysis of proteins constitutes an invaluable tool, granting access to a variety of peptide fragments with potentially interesting biological properties. Therefore, a hemoglobin (Hb) hydrolysate of Crocodylus siamensis was generated by digestion under acidic conditions. The antibacterial and antioxidant activities of the Hb hydrolysate were assessed in comparison with intact Hb. A disc diffusion assay revealed that the Hb hydrolysate exhibited antibacterial activity against eight strains of gram-positive bacteria and showed a higher efficacy than intact Hb. Moreover, the antioxidant activity of intact Hb and its hydrolysate was evaluated using ABTS and DPPH radical scavenging assays. The Hb hydrolysate exhibited free radical scavenging rates of 6-32%, whereas intact Hb showed a slightly higher activity. In addition, non-toxicity to human erythrocytes was observed after treatment with quantities of Hb hydrolysate up to $10{\mu}g$. Moreover, active fragmented Hb (P3) was obtained after purifying the Hb hydrolysate by reversed-phase HPLC. Scanning electron microscopy demonstrated the induction of bacterial cell membrane abnormalities after exposure to P3. Antibacterial and antioxidant activities play crucial roles for supporting the wound healing activity. Consequently, an in vivo mice excisional skin wound healing assay was carried out to investigate the effects of intact Hb treatment on wound healing in more detail. The results clearly demonstrate that intact Hb is capable of promoting 75% wound closure within 6 days. These findings imply that intact Hb of C. siamensis and its acid hydrolysate may serve as valuable precursors for food supplementary products benefitting human health.

• Journal of Life Science
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• v.10 no.2
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• pp.140-149
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• 2000

In order to utilize marine processing waste which would normally be discarded, cod liver protein was hydrolysed by ${\alpha}$-chymotrysin, and the hydrolysate was investigated for the new angiotensin I converting enzyme (ACE) inhibitor. Thy hydrolysate was separated into three major types, with molecular weight cut-off (MWCO) values less than 10 kDa, 5 kDa and 1 kDa of ultrafiltration membranes, respectively. ACE inhibitory peptides were isolated from the fractions passed through MWCO 1 kDa membrane, and purified by using ion-exchange chromatography on a SP-Sephadex C-25 column, gel filtration on a Sephadex G-15 column, and HPLC on an ODS column. The purity was identified with capillary electrophoresis. The amino acid sequences of two peptides were Met-Ile-Pro-Pro-Tyr-Tyr (IC50=10.9 ${\mu}$M) and Gly-Leu-Arg-Asn-Gly-Ile (IC50=35.0 ${\mu}$M)

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.132-140
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• 1998

This study aimed to verify the nutritional and curative effects of protein hydroysate and optimal ratio between protein and protein hydroysate as nitrogen source in rats with cysteamine-induced duodenal ulcer. Duodenal ulcer rat model was established by intraperitoneal injections of cysteamine. Sprague-Dawley, female rats weighing approximately 200g were intrapertionealy injected twice cysteamine(13mg/100g BW) at intervals of 3hours per day. This procedure was repeated 3 times at intervals of 3 days. Animals fed on 10% casein diet for injection periods. After last injection, 5 kinds of kiets (the ratio of casein and casein hydrolysate was 100 : 0(C100), 75 : 25(CH 25), 50 : 50(CH 50), 25 : 75(CH 75), 0 : 100(CH 100)) were given. The rate were sacrificed after feeding diet, 1, 3, 5 days. Ulcer index, hexosamine content of stomach and duodeum, gastric motility, trypsin activity, blood glutathione, plasma total protein, albumin, amino-N, urinalry urea nitrogen, creatinine, hydroxyproline and retention rate of nitrogen were analyzed for nutritional effects of diet treatments. There were no differences among diet groups in the view of the growth and diet treatments. There difference of ulcer curation by diet was appeared after 3 days. The ulcer indexes of C100 and CH 25 of 3, 5 days were significantly higher than those of CH 50, CH 75 and CH 100. This result was the same as hexosamine content of stomach, plasma protein, albumin concentration and nitrogen retention rate. The more casein hydrolysate diet had, the lower trypsin activity was. The more casein gydroysate diet had, the higher excretion of hydroxyproline was. These results show that protein hydrolysate can be applied in diet therapy for the patients with gastronitestinal ulcer. It suggests that it has curative effect of diet when nitogen sources include at least over than 50% of protein hydrolysate.