• Asian-Australasian Journal of Animal Sciences
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• 제29권11호
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• pp.1625-1631
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• 2016

Forty-eight barrows with an average initial body weight of $25.5{\pm}0.3kg$ were assigned to 6 dietary treatments arranged in a $3{\times}2$ factorial of 3 graded levels of P at 1.42, 2.07, or 2.72 g/kg, and 2 levels of casein at 0 or 50 g/kg to compare the estimates of true total tract digestibility (TTTD) of P in soybean meal (SBM) for pigs fed diets with or without casein supplementation. The SBM is the only source of P in diets without casein, and in the diet with added casein, 1.0 to 2.4 g/kg of total dietary P was supplied by SBM as dietary level of SBM increased. The experiment consisted of a 5-d adjustment period and a 5-d total collection period with ferric oxide as a maker to indicate the initiation and termination of fecal collection. There were interactive effects of casein supplementation and total dietary P level on the apparent total tract digestibility (ATTD) and retention of P (p<0.05). Dietary P intake, fecal P output, digested P and retained P were increased linearly with graded increasing levels of SBM in diets regardless of casein addition (p<0.01). Compared with diets without casein, there was a reduction in fecal P in the casein-supplemented diets, which led to increases in digested P, retained P, ATTD, and retention of P (p<0.01). Digested N, ATTD of N, retained N, and N retention were affected by the interaction of casein supplementation and dietary P level (p<0.05). Fecal N output, urinary N output, digested N, and retained N increased linearly with graded increasing levels of SBM for each type of diet (p<0.01). The estimates of TTTD of P in SBM, derived from the regression of daily digested P against daily P intake, for pigs fed diets without casein and with casein were calculated to be 37.3% and 38.6%, respectively. Regressing daily digested N against daily N intake, the TTTD of N in SBM were determined at 94.3% and 94.4% for diets without casein and with added casein, respectively. There was no difference in determined values of TTTD of P or N in SBM for pigs fed diets with or without casein (p>0.05). In summary, our results demonstrate that the estimates of TTTD of P in SBM for pigs were not affected by constant casein inclusion in the basal diets.

• 한국식품과학회지
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• 제27권6호
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• pp.866-870
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• 1995

본 실험에서는 메밀에서 추출한 다당분획이 in vitro에서 casein 가수분해에 미치는 영향을 관찰하였다. 처리방법(날것, 볶은것, 찐것)을 달리한 메밀로부터 추출한 다당중 분자량 10,000 이상의 고분자 가용성다당(HMS-P)과 저분자 불용성다당(LMI-P)이 in vitro에서 trypsin에 의한 casein의 가수분해율을 각각 $80{\sim}89%$, $69{\sim}99%$ 감소시켰으며, 분자량 10,000 이하의 저분자 가용성다당(LMS-P)은 $5{\sim}7%$ 감소시켰다. Chymotrypsin에 의한 가수분해율은 고분자 가용성다당(HMS-P)과 저분자 불용성다당에서 각각 $63{\sim}88%$, $71{\sim}79%$이였으며 저분자 가용성다당은 $2{\sim}5%$였다. Casein 가수분해율을 현저히 감소시킨 볶은 메밀로부터 추출한 다당을 casein과 흔합하여 trypsin과 chymotrypsin으_로 각각 가수분해시킨 후 가수분해산물을 Sephdex G-100 column에 통과시켰다 Casein만 가수분해시켰을 때와 저분자 가용성다방(LMS-P)을 첨가했을 때에 가수분해물은 total volumne에서 1개의 peak가 용출되었으나 고분자 가용성다당(HMS-P)과 저분자 불용성다당(LMI-P)에서는 void volumne에서 고분자량의 peptide peak가 1개 더 용출되었다. Casein 가수분해를 억제하는 고분자 가용성다당(HMS-P)의 구조를 분식한 결과 주로 1,4결합의 glucose로 구성되어 있으며 소량의 1,6결합의 glucose와 단일 glucose도 함유되어 있었다. 따라서 메밀로부터 추출한 고분자 가용성다당분획에 의한 casein 가수분해율의 감소는 다당에 의한 것이라기 보다는 괌자량 10,000이상의 수용성물질에 의한 것으로 추측된다.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.10-15
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• 1996

To determine the quality of heated protein, in vitro method, invluding lysine, lysionalanine, and fructose-lysine as well as homoarginine by guanidination of lysine, was assessed using heated casein with of without glucose. In vivo methods such as PER, digestibility and BV were also tried on homoarginine, lysinoalanine, fructoselysine, and lysine. The nonreactive lysine for huanidination was hardly digestive, while the non heat damaged lysine side chanis in the protein were accessible for guanidination as well as for the digestion. A linear correlation(${\gamma}$=0.80) was obstained between PER and digestibility of the analysed lysine. Digestibility of homoarginine was higher that of true protein. However, in the guanidinated heated casein with glucose, digestibility of homoarginine was significantly reduced. It is suggested that the homoarginine method may mislead to over- or underestimation of the damaged protein quality.

• Applied Biological Chemistry
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• 제24권1호
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• pp.67-73
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• 1981

보리와 발아보리의 생체내 영양효율을 알기위해 동물실험을 행하였다. 젖뗀 albino rat를 사용하여 단백질원으로 보리 및 발아보리만을 사용한 군, 단백질(5%의 casein)을 첨가해준, 그리고 쌀(쌀:보리=8:2) 및 단백질(5% casein)을 혼합 첨가시킨군으로 나누어 4주간 사육하여 다음과 같은 결과를 얻었다. 1. 식이 및 열량섭취량, 식이의 효율 및 체중은 보리 및 발아보리에 단백질을 첨가시킨군들에서 높았으며 쌀과 단백질을 첨가시킨군들에서는 현저히 높아 통계적으로 유의성을 보였다. 그러나 보리군들과 발아 보리군들간의 차이는 볼 수 없었다. 2. 단백질의 효율은 단일 곡류군들과 단백질 첨가군들에 비해 쌀과 단백질 혼합첨가군들이 높음을 보여 흔합된 곡류단백질이 체내효율을 높이는 것으로 나타났다. 3. 식이 및 단백질의 소화흡수율을 보면, 단일곡류군들에서는 표준군에 비해 보리군 및 발아보리군들이 낮음을 보였다. 그러나 여기에 단백질 또는 쌀과 단백질을 혼합 첨가하였을 경우 보리군들에 비해 발아보리군들의 단백질 소화흡수율이 현저히 증가하였다. 따라서 발아보리의 영양효과는 발아보리와 함께 동물성단백질을 적당히 섭취할 경우 단백질의 소화흡수율을 크게 증가 시키는데 있다고 할 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제11권1호
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• pp.13-16
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• 1998

A $2{\times}2{\times}4$ factorial study was conducted to examine the possibility of improving estimates of in vitro digestibility, using untreated (UBS) and ammonia-treated (ABS) barley straw, through homogenization of rumen fluid (RF) and by additions of urea (U) and casein (C) as N sources and Xylose + Glucose (XG) as energy sources into artificial saliva. Digestibiltiy of ABS was significantly greater than that of UBS (p < 0.001). There was a significant decrease in digestibility when additions (U, UC, UCXG) were compared with the control (p < 0.001). A 2-way interaction between RF and straw type was significant (p < 0.05) for dry matter digestibility (DMD). Homogenization of RF increased DMD of ABS (p < 0.05) whereas it decreased DMD of UBS (p > 0.05). The study showed that addition of N alone or in combination with energy sources was not better than control, rather the reverse, digestion was inhibited by a combination of U and casein (UC). It was concluded that sufficient N and branched chain fatty acids were supplied in the inoculum from sheep fed high protein grass cubes to support the growth of cellulolytic microbes during in vitro incubation. Further studies are, however, required to explore the potential of homogenization in improving the in vitro method to estimate digestibility of cereal straws.

• Asian-Australasian Journal of Animal Sciences
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• 제15권11호
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• pp.1634-1638
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• 2002

Quantification of endogenous amino acid loss at the terminal ileum is an essential means for calculation of the true amino acid digestibility of a feedstuff. Since nitrogen appeared in the determined diet or not could shift the results very much, also, none of digestibility markers could be recovered with 100% rate at the terminal ileum, the objectives of the present study were: (1) to determine endogenous amino acid losses when fed either a casein diet or a protein-free diet and (2) to examine the reliability of chromic oxide or acid insoluble ash in the protein-free diet. Six ileal-cannulated pigs ($65{\pm}1.85 kg$ BW) with a simple T-cannula in the terminal ileum were used in a replicated $3{\times}3$ Latin square designed trial, after allowed a 14 d recuperation period. Each test period ran for 12 days comprised of a 10 d adjustment period and a 2 d collection period. The endogenous AA losses of His, Ile, Lys, Cys, Thr, Val, Trp, Asp, Glu, and Ser from pigs fed the casein diet were significantly higher than those of the protein-free diet (p<0.05). No significant difference was found in the amount of endogenous amino acid loss when determined with the different markers in the protein-free diet (p>0.05). These data suggest that endogenous amino acid loss could be underestimated when a protein-free diet is used. A direct effect of dietary peptides on the endogenous amino acid loss was found when the casein diet was fed. Our results also indicate that acid insoluble ash can be used as an inert marker as an alternative to chromic oxide when measuring endogenous amino acid loss.

• 생명과학회지
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• 제5권2호
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• pp.57-62
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• 1995

Casein or soybean protein was subjected to there action with caffeic acidtyrosinase system at 30-35$\circ$C, pH 6.8 with aeration for 5hr. The resulting brown proteins were washed with acetone until the washings were on longer colored. However, modified protein still retained a light brown. The effects of the modified proteins and brown compounds on male Wistar strain rats were studied by pair-feeding of a cholesterol-free diet for 14days. Significant decrease in protein digestibility for the rats fed with the modified proteins were observed. Weight gain and protein digestibility were not influenced by feeding brown compounds, but the feeding of brown compound from casein caused an enlargement of caecum. The concentrations of serum cholesterol and triglyceride in the rats fed with modified proteins and brown compounds were mostly unchanged against the rats fed with untreated proteins. These results suggest that the decrease in protein digestibility induced by enzymic browning-reaction did not cause the decrease in concentration of serum cholesterol.

• Journal of Dairy Science and Biotechnology
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• 제34권3호
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• pp.173-180
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• 2016

In many countries, goat milk is an excellent nutrient source and is less allergenic for children and the elderly. The casein composition of goat milk consists largely of ${\beta}$-casein and lower amounts of ${\alpha}_{s1}$-casein, which may interfere with digestion by forming solid curds in the human stomach. Goat milk contains small fat globules and large amounts of medium chain fatty acids for, better digestibility, as well as abundant minerals and vitamins with high absorption rates. Recently, the medical benefits of goat milk in different human disorders have been recognized, leading to an increased interest in developing functional foods with goat milk, particularly for individuals with malabsorption syndrome. However, the physiological and biochemical properties of goat milk are largely unknown. We review the importance of goat milk as a potential functional food by providing scientific evidence confirming its health benefits.

• 한국축산식품학회지
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• 제37권6호
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• pp.940-947
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• 2017

Goat milk has a protein composition similar to that of breast milk and contains abundant nutrients, but its use in functional foods is rather limited in comparison to milk from other sources. The aim of this study was to prepare a goat A2 ${\beta}$-casein fraction with improved digestibility and hypoallergenic properties. We investigated the optimal conditions for the separation of A2 ${\beta}$-casein fraction from goat milk by pH adjustment to pH 4.4 and treating the casein suspension with calcium chloride (0.05 M for 1 h at $25^{\circ}C$). Selective reduction of ${\beta}$- lactoglobulin and ${\alpha}_s$-casein was confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. The hypoallergenic property of A2 ${\beta}$-casein fraction was examined by measuring the release of histamine and tumor necrosis factor alpha from HMC-1 human mast cells exposed to different proteins, including A2 ${\beta}$-casein fraction. There was no significant difference in levels of both indicators between A2 ${\beta}$-casein treatment and the control (no protein treatment). The A2 ${\beta}$-casein fraction is abundant in essential amino acids, especially, branched-chain amino acids (leucine, valine, and isoleucine). The physicochemical properties of A2 ${\beta}$-casein fraction, including protein solubility and viscosity, are similar to those of bovine whole casein which is widely used as a protein source in various foods. Therefore, the goat A2 ${\beta}$-casein fraction may be useful as a food material with good digestibility and hypoallergenic properties for infants, the elderly, and people with metabolic disorders.

• 한국식품영양과학회지
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• 제19권5호
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• pp.387-394
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• 1990

The effect of lysine or methionine addition on the lipid oxidation and protein properties in casein-fish oil model system during the storage of 21 days at 37$^{\circ}C$ was studied. The peroxide and TBA values were increased markedly and the amino acids addition to the system caused to reduce the extent of lipid oxidation in comparison with that of casein-fish oil system which was a control group. Significant changes in fatty acid composition of each group were observed. Polyenoic acid contents were drastically decreased during the storage in the groups with and without the amino acids additions, . And also significant losses of several amino acids were occurred with the reduction of solubility and digestibility of casein during the storage. However no different effects were observed in both additionsof lysine and methionine to the system.