• Korean Journal of Food Science and Technology
• /
• v.27 no.5
• /
• pp.794-798
• /
• 1995

Deamidation by neutrase on glutaminyl and asparaginyl residues of protein was examined. The optimum pH and temperature for BSA(bovine serum albumin) deamidation by neutrase were 10 and $20^{\circ}C$, respectively. The incubation for 3 hrs under the optimum condition removed 24% of amide groups and hydrolyzed 2.9% of peptide bonds. Deamidation by neutrase was superior to that by pronase, bromelain, or ficin. Deamidation degrees of egg albumin, soy protein isolate and casein by neutrase under the optimum condition were about 20%, 14% and 14%, respectively. However, relatively high degree of peptide hydrolysis was accompanied with casein deamidation.

• The Korean Journal of Mycology
• /
• v.14 no.1
• /
• pp.25-30
• /
• 1986

The purposes of this study were to investigate enzyme components and its physiological activities of Sarcodon aspratus (Berk.) S. Ito which grows wildly in Korea, belonging to the family Thelephoraceae. The carpophores of the fungus was extracted with cooling distilled water and salted out by ammonium sulfate. The precipitate was purified by dialysing through visking tube against distilled water and then dissolved with pH 7.8 ammonia aqua, and the extract was filterated. The fraction of filtrate was obtained as light brown powder after lyophilization and determined proteolytic activity. Protease activity of Sarcodon aspratus (Berk.) S. Ito was about two-third of that of pepsin on casein by cup method. The proteolytic potency of this enzyme was found to be 500 unit/mg. This proved the efficacy of the mushroom when it was used as a folk medicine for treating indigestion of beef.

• Korean Journal of Food Science and Technology
• /
• v.25 no.3
• /
• pp.277-281
• /
• 1993

To elucidate the conformational stability of proteins in colloidal food system, molecular properties of various proteins such as chemically modified ${\beta}-lactoglobulin$, bovine serum albumin (BSA) structural intermediates, and ${\beta}-casein$ under chaotropic conditions, were examined using circular dichroism, SS bond content, and hydrodynamic radius determination. As refolding time increases, BSA intermediates approach the conformation of native BSA. And succinylation made ${\beta}-lactoglobulin$ have more aperiodic structure by increasing net negative charge. Also, under chaotropic conditions, the conformation of P-casein was affected by hydrophobic interactions. This study clearly indicates that hydrophobic interactions and electrostatic interactions are major contributing factors in conformational stability of proteins.

• Food Science of Animal Resources
• /
• v.39 no.5
• /
• pp.725-741
• /
• 2019

In the current study, we first investigated a method for directly transforming lactose into galacto-oligosaccharides (GOS) for manufacturing low-lactose and GOS-enriched skim milk (GSM) and then evaluated its prebiotic potential by inoculating five strains of Bifidobacterium spp. In addition, fermented GSM (FGSM) was prepared using a potentially probiotic Lactobacillus strain and its fermentation characteristics and antioxidant capacities were determined. We found that GOS in GSM were metabolized by all five Bifidobacterium strains after incubation and promoted their growth. The levels of antioxidant activities including radical scavenging activities and 3-hydroxy-3-methylglutaryl-CoA reductase inhibition rate in GSM were significantly increased by fermentation with the probiotic Lactobacillus strain. Moreover, thirty-nine featured peptides in FGSM was detected. In particular, six peptides derived from ${\beta}$-casein, two peptides originated from ${\alpha}s_1$-casein and ${\kappa}$-casein were newly identified, respectively. Our findings indicate that GSM can potentially be used as a prebiotic substrate and FGSM can potentially prevent oxidative stress during the production of synbiotic fermented milk in the food industry.

• Journal of the Korean Wood Science and Technology
• /
• v.31 no.1
• /
• pp.22-26
• /
• 2003

Particleboards (PBs) were made from Pinus densiflora thinning particle with urea-formaldehyde (UF) resin added casein and soybean as extender. The performance test results of the PB made showed that Pinus densiflora thinning log was suitable raw material for PB. As the extender addition in the UF resin was increased, the mechanical performance of the PB, bonded with the extended UF resin, were significantly decreased. However, casein and soybean can be used up to 15% and 20% of the UF resin solids respectively.

• Journal of Dairy Science and Biotechnology
• /
• v.40 no.4
• /
• pp.173-181
• /
• 2022

Industrial-scale Ca-fortified Dangmyon was manufactured with added casein phosphopeptides (CPP) to increase Ca adsorption in the intestine. Very low P content in eggshell Ca (egg Ca) and Dangmyon could make it possible to indirectly measure CPP content in Dangmyon. Partitions of the whole P present in Dangmyon were made into sweet potato, egg Ca, and CPP. The CPP content was obtained by multiplying CPP per P by the amount of P partitioned into CPP. It was found that 88.46% of CPP was obtained. However, when milk Ca, which was much higher in P, was added to fortify Dangmyon with CPP, it was found that the CPP content was either under- or over-estimated. Care must be taken when a much higher content of P as a Ca source is selected using this method. It was discovered that the added Ca and CPP were retained after cooking at boiling temperature; therefore, Dangmyon could be an excellent Ca and CPP carrier for humans.

• Korean Journal of Food Science and Technology
• /
• v.6 no.2
• /
• pp.75-78
• /
• 1974

An experiment has been carried out in order to analyze the main components of Korean Cattles' milk, and fractionate the milk protein by DEAE-cellulose column. The results obtained were summarized as follow. 1) The average values of specific gravity, pH and acidity of Korean Cattles milk which were negative in alcohol test were 1,036, 6.4 and 0.21, respectively. 2) The average values of total solids, solids-not-fat, protein, lactose and ash contents of Korean Cattles milk were 11.61%, 9.53%, 2.08%, 3.99%, 4.76% and 0.86%, respectively. 3) Distribution of casein, whey protein, N.P.N., protein precipitated in 12% TCA, lactoglobulin and lactalbumin contents of the milk were 3.07%, 1.13%, 0.10%, 4.06%, 0.34% and 0.66%, respectively. 4) Acid casein obtained from Korean Cattles milk was fractionated into four fractions on DEAE-cellulose column with 0.005M tris-citrate buffer containing 6M urea, pH 8.6, and the ratio of the fraction I, II, III and IV was 3.24%, 52.67%, 26.22% and 17.87%, respectively. 5) Whey protein obtained from Korean Cattles milk was also fractionated into four fractions on DEAE-cellulose column with 0.04M phosphate buffer, pH 5.8, and the ratio of the fraction I, II, III and IV was 41.74%, 10.17%, 1.50% and 46.59%, respectively.

• Korean Journal of Food Science and Technology
• /
• v.20 no.5
• /
• pp.659-665
• /
• 1988

The ${\alpha}_{s1}$-and ${\beta}$-casein were purified by DEAE-cellulose chromatography and digested with alkaline protease from Bacillus subtilis. Bitter fractions from the hydrolyzates were isolated using n-butanol extraction, Sephadex G-25 gel chromatography, and high performance liquid chromatography. Peptide mixtures were separated by reverse-phase octadecyl silica column with linear gradient of 0-80% acetonitrile containing 0.1% trifluoroacetic acid. Major peaks were combined from replicate chromatographies and the bitterness of each peak was evaluated. The bitter-tasting peaks were rechromatograpied until isolated peaks were obtained. Three different bitter peptides(BP-I, BP-II, BP-III) were obtained from the ${\alpha}_{s1}$-casein hydrolyzate. BP-I was eluted at 34% acetonitrile and BP-II, 35%, BP-III, 26%, respectively. Two bitter peptides(BP-IV, BP-V) were isolated from the ${\beta}-casein$ hydrolyzate: BP-IV was eluted at 40% acetonitrile and BP-V, 42%. BP-V was the most hydrophobic peptide in the five bitter peptides. However, BP-I and BP-II tasted more bitter than BP-IV and BP-V.

• Journal of Animal Science and Technology
• /
• v.44 no.4
• /
• pp.483-490
• /
• 2002

The aim of this study was to determine if a low-molecular weight casein hydrolysate has an anti- hypertensive effect in spontaneously hypertensive rats (SHR). Prior to the in vivo experiment, the casein hydrolysate was confirmed to be resistant to gastrointestinal digestion by confirming the retention of its potency as an inhibitor of angiotensin I-concerting enzyme after incubation with pepsin, trypsin, or chymotrypsin. The in vivo anti-hypertensive effect of the hydrolysate was determined by the tail cuff method. Following an oral administration of the hydrolysate solution, the systolic blood pressure (SBP) decreased by 12.9% (－28.9mmHg; P<0.05) at 3 h after the administration at a dose of 500mg/kg body weight. When the hydrolysate was administered as an emulsion with 30% egg yolk, its anti-hypertensive effect was even more greater at the same dose(－30.8mmHg or －15.9%; P<0.01). In a 50-day long-term trial where the casein hydrolysate was administered once a day, the SBP-lowering effect of the hydrolysate was apparent (P<0.05) from day 35 through the end. Moreover, organ weights and plasma glutamate oxaloacetate transaminase and glutamate pyruvate transaminase activities of the administered SHR were not significantly different from those of controls at the end of the long-term trial.

• Journal of Sericultural and Entomological Science
• /
• v.17 no.2
• /
• pp.133-139
• /
• 1975

For developing the therapeutic agents to be administered orally for treating certain silkworm diseases and applying them to clinical conditions, vehicles suitable for the agents are needed. The author presumed that Lactose, Casein, and Urea, respectively, have an effectiveness as the vehicle. A series of experiments were carried out on these substances for conforming the applicability of the vehicles at the silkworm rearing house of the College of Agriculture, at Seoul National University during the spring silkworm rearing season of 1974 and the spring and autumn seasons of 1975. The author recognized, Lactose, Casein, and Urea, when put on the mulberry leaves in a powdered form, are eaten along with the leaves by silkworm. Thus, the systemic administration of them to silkworms are possible. The author administered these individual substances orally to silkworm larvae in doses of l0mg., 30mg., 50mg., and 100mg. per gram of the body weight of the silkworm larvae at intervals of once a day, once every two days, and once every three days for 15 days. This was carried out from the first day of the fourth instar to just before mounting. The influences of these substances on the growth of silkworm larvae and the cocoons made by the larvae were observed. The author found out after completing the experiment that Lactose had no effect on growth and cocoon formation. This was observed in all cases. Casein inhibited the growth of silkworms except in the case of administered doses of once every third day in whick the growth and the cocoons were normal but the administration of the agent brought considerably large numbers of abnormal cocoons in every case. Urea inhibited both the growth and the formation of tile cocoons in most cases. For the confirmation of the clinical effectiveness as the vehicles for some therapeutic agents, the three substances, Lactose, Casein, and Urea, will be investigated more closely for the mixing amounts needed and other pertinent data.