• Title/Summary/Keyword: Casein

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Some Physicochemical Properties of Bovine Colostral Casein Micelles (젖소 초유 Casein Micelle의 이화학적 성질에 관한 연구)

  • Lee, Chul-Won;Kim, Young-Kyo
    • Korean Journal of Food Science and Technology
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    • v.20 no.2
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    • pp.170-175
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    • 1988
  • This experiment was carried out to study the properties of casein micelles obtained from colostral skim milk. As lactation was progressed from parturition until 240h after calving, the content of total protein decreased while the proportion of casein to whey protein increased. Fractionaltion according to the site of casein micelle was done by ultracentrifugation at 100,000 x g for 10 minutes(pellet 1), 30 minutes(pellet 2) and 60 mintes(pellet 3) and the serum casein was prepared by acid precipitation of final supernatant at pH 4.6. During the lactation period, the relative amount of pellet 1(large size) decreased, that of pellet 2(middle size) maintained nearly constant level except for pllet from parturition, that of pellet 3(small size) increased, and the serum casein showed almost constant level. The relative amounts of ${\alpha}_{s1}-casein\;and\;{\alpha}_{s2}-casein\;and\;{\beta}-casein-5P$ in the pellets decreased and that of x-casein increased markedly with decreasing micelle size, but the relative amounts of ${\beta}-casein-1P$(f 29-209), (f 106-209) and (f 108-209) showed little change. The composition of the serum casein was different from that of the skim milk casein.

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Effects of Protein and Protein Hydrolysate on Nitrogen Metabolism in Rats with Cysteamine-induced Duodenal Ulcer (Cysteamine에 의해 유도된 십이지장 궤양 흰쥐의 체내질소대사에 대한 단백질과 단백질 가수분해물의 섭취효과)

  • 이연숙
    • 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.

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Effect of Protein and Protein Hydrolysate on Nitrogen Metabolism in Rats with Gastric Ulcer Induced by Restraint and Water-Immersion Stress (단백질과 단백질 가수분해물이 침수 속박 스트레스로 유도된 위 궤양 흰쥐의 질소대사에 미치는 영향)

  • 김창임
    • 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.

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Effects of cultural conditions on growth of Micrococcus sp. and casein hydrolysis : (II) -Studies on patterns of casein hydrolysis with time during culture- (Micrococcus sp.의 생육 및 casein 분해에 미치는 배양조건의 영향 : (II) -배양시간에 따른 casein 분해 형태에 관한 연구-)

  • Lee, Si-Kyung;Pec, Un-Hua;Joo, Hyun-Kyu
    • Applied Biological Chemistry
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    • v.35 no.6
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    • pp.479-484
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    • 1992
  • This study was undertaken to determine the effects of cultural conditions on cell growth and casein hydrolysis for cell production in order to add Micrococcus sp. LL3 as a potential agent for industrial application with aim of shortening ripening period and improving flavor. Optimum temperature for cell growth and caseinolysis was $30^{\circ}C$ and $37{\circ}C$, respectively, and optimum pH was 7.0. The enzyme remained stable up to $50^{\circ}C$. Hydrolysis patterns of casein were also observed on SDS-PAGE. Both ${\alpha}-casein$ and ${\beta}-casein$ were totally hydrolysed by enzymes from Micrococcus sp. LL3 during culture. A preferential attack on ${\beta}-casein$ was observed. Production of aminopeptidase which cleaved polypeptides was the highest in early stationary phase during cell growth.

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MILK PROTEIN POLYMORPHISMS AS GENETIC MARKER IN KOREAN NATIVE CATTLE

  • Chung, E.R.;Han, S.K.;Rhim, T.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.8 no.2
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    • pp.187-194
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    • 1995
  • Genetic variants of ${\alpha}s_1$-casein, ${\beta}$-casein, ${\kappa}$-casein and ${\beta}$-lactoglobulin were investigated by starch urea gel electrophoresis in milk samples of 280 Korean native cattle. A new ${\beta}$-casein variant, designated ${\beta}$-casein $A^4$, was found in milk samples of Korean native cattle. It has a much slower electrophoretic mobility than the ${\beta}$-casein $A^3$ variant in acid gel. This new variant appeared together with either ${\beta}$-casein $A^1$, $A^2$ or B variant. Gene frequencies and genotypic frequencies were estimated. Gene frequencies of four milk protein loci in Korean native cattle were compared with those of imported cattle breeds raised in Korea and Japanese brown cattle. Gene frequencies were ${\alpha}s_1$-casein B .846, ${\alpha}s_1$-casein C .154; ${\beta}$-casein $A^1$ .216, ${\beta}$-casein $A^2$ .666, ${\beta}$-casein $A^4$ .048, ${\beta}$-casein B .070; ${\kappa}$-casein A .648, ${\kappa}$-casein B .352; ${\beta}$-lactoglobulin A .148, ${\beta}$-lactoglobulin B .852. The population was in Hardy-Weinberg equilibrium at all milk protein loci. Gene frequencies of Korean native cattle were very similar to those of Japanese brown cattle. Interestingly, a new variant, ${\beta}$-casein $A^4$, was found only in Korean native cattle and Japanese brown cattle. These results support the hypothesis that Korean native cattle were used in the development of the Japanese brown cattle.

The Changes of Casein of Cheese Base Treated with Enzyme during Ripening (Enzyme의 처리에 의한 Cheese Base의 숙성중 Casein의 변화)

  • Lee, Gang-Ik;Cha, Gwang-Jong;Yu, Je-Hyeon
    • 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.

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Emulsion Properties of Casein-Alginate Mixtures (카제인-알긴산 혼합물의 유화특성)

  • 황재관;최문정;김종태
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.6
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    • pp.1102-1108
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    • 1997
  • Proteins and polysaccharides confer distinct functional properties in food systems. This research was attempted to improve emulsion properties of casein by protein-polysaccharide conjugation, in which alginates with various molecular weights were employed as polysaccharide sources. Casein-alginate mixtures were conjugated by the amino-carbonyl or Maillard reaction at 6$0^{\circ}C$ and 79% relative humidity. The resulting casein-alginate conjugates were tested for their emulsion activity and emulsion stabilizing properties. In general, the emulsion stability of casein-alginate mixture greatly increased due to the amino-carbonyl reaction between casein and alginates, whose magnitude depended on the molecular weight of alginate, weight ratio of casein to alginate and incubation time. It was also found that thermal stability and pH stability were markedly improved by the casein-alginate conjugation.

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Secretion of Bovine $\beta$-Casein by Saccharomyces cerevisiae

  • Chung, Kun-Sub;Rafael, F.R.;Oh, Sang-Suk;Richardson, T.
    • Journal of Microbiology and Biotechnology
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    • v.1 no.1
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    • pp.31-36
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    • 1991
  • Yeast expression plasmids containing an appropriate leader sequence and bovine $\beta$-casein cDNA were constructed to produce $\beta$-casein for the study of its functional characteristics. Two kinds of expression systems for $\beta$-casein were constructed using pCGYl444 as a precursor plasmid. This plasmid is a yeast-E. coli shuttle vector which contains the chelatin promoter. The plasmid pISB202 contains the invertase leader sequence and $\beta$-casein gene. The plasmid pDEB303 contains the original bovine $\beta$-casein leader sequence gene. These two plasmids were introduced into S. cerevisiae AB116 which is a strain deficient in the major yeast proteinases. Each clone was grown in minimal media for 24 h before induction by $CuSO_4$. The cells were thus grown under expression conditions. Both strains harbouring pISB202 and pDEB303 expressed bovine $\beta$-casein. The $\beta$-casein was detected using immunochemical staining after western blot. Secretion of $\beta$-casein was detected in the culture broth. The estimated amount of secreted $\beta$-casein was approximately 50 ${\MU}g$/l.

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Fractionation and Physicochemical Characteristics of Caprine Casein by DEAE-Cellulose (DEAE-Cellulose에 의한 산양유 Casein의 분별 및 이화학적 성질에 관한 연구)

  • Im, Dong-Hyeon;Jeon, U-Min;Han, Gyeong-Sik;Kim, Byeong-Cheol;Hwang, Gwang-Yeon;Kim, Se-Heon
    • Journal of Dairy Science and Biotechnology
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    • v.18 no.1
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    • pp.1-8
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    • 2000
  • This experiment was carried out to study fractionation and physicochemical characteristics of caprine casein. Acid caseins obtained from caprine colostral and normal milk were analyzed by chymosin treatment and fractionated by DEAE-cellulose column chromatography with linear gradient and electrophoresis. Protein, fat and lactose of caprine normal milk were 2.70${\pm}$0.27%, 3.82${\pm}$0.51%, and 4.10${\pm}$0.29%, respectively. More non-protein nitrogen(NPN) was released by chymosin treatment from caprine colostral casein than normal casein. The electrophoretic pattern of caprine casein was not similar to that of bovine casein, Caprine normal casein was fractionated by DEAE-cellulose column chromatography with a 0.08${\sim}$0.18 M NaCl linear gradient into 5 pes with the proportion of 5.27%, 26.07%, 25.97%, 30.40% and 12.29%, respectively. In order to identify the pure fraction, the chymosin-treated caprine normal casein was fractionated by DEAE-cellulosecolumn chromatography with a 0.08${\sim}$0.18 M NaCl linear gradient into 6 peaks with the proportion of 17.06%, 9.10%, 17.85%, 20.11%, 27.03% and 8.85%, respectively.

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Hydrolysis Characteristics of Goat Milk $\beta-Casein$ by Enzyme and Angiotensin Converting Enzyme Inhibition Effects of Hydrolysate (산야유 $\beta-Casein$의 효소 가수분해 특성과 가수분해물의 Angiotensin Converting Enzyme 저해 효과)

  • Park Yong-Kuk;Kwon Il-Kyoung;Kim Gur-Yoo
    • Food Science of Animal Resources
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    • v.25 no.2
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    • pp.238-243
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    • 2005
  • This study was carried out to understand hyrolytic characteristics of $\beta-casein$ by enzyme in goat milk and to measure the inhibition effect of the ACE of the hydrolysate. In order to conduct the experiment, $\beta-casein$ of goat milk was separated using Mono S HR 5/5, a cation exchange column. The separated $\beta-casein$ was treated with trypsin of animal hydrolysis enzymes, in an effort to verify the characteristics of hydrolysis. The inhibition activity of ACE was measured and the results are as follows. By analyzing the hydrolysate separated from the trypsin-processed $\beta-casein$ of goat milk, the inhibition effect of the ACE was measured trypsin-hydrolyzed $\beta-casein$ demonstrated a $25.36\pm0.79\%$ of inhibition effect and the $IC_{50}$ of the hydrolysate from the trypsin-processed $\beta-casein$ reached $308.7\pm2.77({\mu}g/mL)$.