• Asian-Australasian Journal of Animal Sciences
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• v.29 no.11
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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.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.866-870
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• 1995

This study was conducted to determine the effect of soluble polysaccharides and indigestible polysaccharides on the digestibility of casein in vitro and the structure of polysaccharide. The digestibility of casein by trypsin in vitro was reduced to $80{\sim}89%$ and $69{\sim}99%$ by high molecular soluble polysaccharide (HMS-P) and low molecular insoluble polysaccharide (LMI-P) prepared from buckwheat, respectively. The digestibility of casein by chymotrypsin was reduced to $63{\sim}88%$ and$71{\sim}79%$ by HMS-P and LMI-P, respectively. But casein digestibiliy by trypsin and chymotrypsin was slightly reduced by LMS-P. The casein hydrolyzates inhibited by HMS-P gave a main peak in the void volume on Sepadex G-100, but the peak in the total volume was only appeared in case of LMS-P having no inhibito교 effect. It was suggested that the HMS-P was consisted of 4-linked and 4,6-dissubstituted glucose from the structural analysis by GC.

• Preventive Nutrition and Food Science
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• v.1 no.1
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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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• v.24 no.1
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• pp.67-73
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• 1981

This study was conducted to investigate the nutritional value of germinated barley with animal experiment. Fourthyeight weanling albino rats, which were divided into 8 groups, were fed during 4 weeks. The feed intake, energy intake, FER (feed efficiency ratio) and growth rate were slightly high in the casein supplemented groups and were significantly high in the rice and casein supplemented groups. But there was no a significant difference between the barley and germinated barley groups. A higher PER (protein efficiency ratio) was shown in the rice and casein supplemented groups. It was induced that mixed cereal protein increase the PER compared to simple cereal protein. Low apparent digestibility of the diet and of the protein were found in barley and germinated barley groups compared to standard and rice groups. But apparent digestibility of protein in germinated barley groups were markedly increased by the supplementation of 5% casein or supplementation of rice and casein. From this result it was concluded that germinated barley has a nutritional effect on increasing protein digestibility when added enough amount of animal protein.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.1
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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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• v.15 no.11
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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.

• Journal of Life Science
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• v.5 no.2
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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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• v.34 no.3
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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.

• Food Science of Animal Resources
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• v.37 no.6
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.5
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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.