• 한국식품영양과학회지
• /
• 제30권3호
• /
• pp.505-509
• /
• 2001

This study was carried out to evaluate the application of food irradiation technology as a method for reducing milk allergies. Bovine $\alpha$-casein, $\beta$-casein, $textsc{k}$-casein, $\alpha$-lactalbumin(ALA), $\beta$-lactoglobulin (BLG) and serum albumin (BSA) were used as model allergens of milk proteins and the proten solution (2.0 mg/mL) with 0.01 M phosphate buffered saline (pH 7.4) was irradiated at 3, 5 and 10 kGy. Using milk-hypersensitive patients IgE (MHP-IgE), the changes of binding ability to irradiated proteins were observed by competitive indirect enzyme-linked immunosorbent assay (Ci-ELISA). Affinity of MHP-IgE to milk proteins was higher in ALA and BLG than that of other proteins. Standard curve to each non-irradiated protein could be made with MHP-IgE for quantifying milk allergens. Binding abilities of MHP-IgE to the irradiated proteins, however, decreased with different slopes of the standard curves. Sensitivity of gamma irradiation was higher in ALA and BLG than of other proteins. These results indicated that irradiation technology can be used to reduce the milk hypersensitivity.

• 한국식품과학회지
• /
• 제31권6호
• /
• pp.1648-1653
• /
• 1999

새우젓으로부터 혈전용해효소를 생산하는 균주를 분리하여 Bacillus sp.로 동정하였다. Bacillus sp. S19는 screening 배지에서는 18 U/mL의 효소를 생산하였다. 그러나 2% soluble starch, 2% skim milk, 3% NaCl(pH 7.5)의 최적화된 배지로 $37^{\circ}C$에서 72시간 동안 배양하였을 경우 효소활성이 약 3배 증가된 62 U/mL의 효소 생산을 결과하였다.

• Applied Biological Chemistry
• /
• 제21권3호
• /
• pp.137-143
• /
• 1978

소의 갑상선에 있는 xanthine oxidase 효소도 flavin adenine dinucleotide(FAD), 모리브덴 및 철을 cofactor로서 가지고 있었으며 그 비율은 1 : 0.36 : 1.6이었다 갑상선 xanthine oxidase의 분자량은 gel filtration과 gel electrophoresis방법으로 측정하였을 때 우유에서 추출한 xanthine oxidase의 분자량과 큰 차이가 없었다. 그 효소의 활성도는 pH7.8에서 가장 높았고 isoelectric point는 electrofocusing으로 측정하였을 때 pH 6.2 였다. SDS-polyacrylamide gel electrophoresis 실험 결과는 소의 갑상선에서 추출된 xanthine oxidase가 세개의 subunit로 분해되었음을 지적했고, 최소 단위분자량 65,000정도의 polypeptide 4개로서 완전한 xanthine oxidase 한 분자를 구성하고 있을 가능성을 보였다. 갑상선 호소의 absorption spectrum을 우유에서 추출된 효소와 비교하였을 때 상당한 상이점을 나타내었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제20권2호
• /
• pp.273-282
• /
• 2007

This study was carried out to compare the changes of nutrients, sensory and chemical properties of freeze-concentrated and evaporated milks during storage. For pasteurization, the freeze-concentrated milk containing 27% of total solid was treated with 150 rpm ozone for 5 min, and 99% of microflora was eliminated. Also, the activities of protease and lipase decreased 93.31% and 96.15%, respectively, and phosphatase showed negative activity. Total bacteria count was maintained below$2.0{\times}10^4$CFU/ml. During storage, TBA absorbance was lower in freeze-concentrated milk than that in the evaporated milk. The production of short-chain free fatty acids and free amino acids increased proportionally to the storage period in both samples. While the short-chain free fatty acid production was lower in the freeze-concentrated milk compared with that in the evaporated milk, the production of individual free amino acid was similar in both samples. In sensory evaluation, cooked flavor and color were much lower in the freeze-concentrated milk than that in the evaporated milk. Overall acceptability score was higher in the freeze-concentrated than the evaporated milk. Based on above results, ozone treatment for the freeze-concentrated milk pasteurization was positive at the elimination of microflora and enzyme inactivation. During storage, the freeze-concentrated sample minimized the change of color and TBA absorbance, the production of short-chain free fatty acid and vitamins than the evaporated milk. Therefore, the freeze-concentrated milk process in the present study resulted in the positive effect in minimizing nutrient loss and keeping quality of milk during storage.

• 환경위생공학
• /
• 제5권2호
• /
• pp.103-110
• /
• 1990

For production of thermophilic and alkaline protease, Bacillus sp. strain AP-5 was isolated from a compost. The production of the protease was reached at maximum for 4 days at $55^{\circ}$ in standing culture. Chitin and Cellulose as carbon source, and Skim Milk as nitrogen source were favorable for the production of the enzyme. Optimal temperature and optimal pH of the enzyme was $55^{\circ}$ and 11, respectively. Metal ion didn't effect on the enzyme activity, the protease was very stable at heat treatment of 30 min at $55^{\circ}$.

• 한국축산식품학회지
• /
• 제25권2호
• /
• pp.238-243
• /
• 2005

산양유 $\beta-casein$의 효소에 의한 가수분해 특성과 가수분해물의 ACE 저해 효과를 측정하고자 산양유의 $\beta-casein$을 양이온 교환 컬럼인 Mono S HR 5/5를 이용하여 분리하였으며 분리된 $\beta-casein$을 동물성 분해효소인 trypsin으로 처리하여 가수분해 특성을 확인하였고 가수분해물의 ACE 저해활성을 측정하였다. Mono S HR 5/5 양이온 교환 컬럼을 이용한 산양유 산 케이신으로 부터 순수한 $\beta-casein$의 분리는 SDS-PAGE를 이용하여 확인한 결과 순수한 $\beta-casein$의 분리가 이루어졌음을 확인할 수 있었다. $\beta-casein$을 $37^{\circ}C4$에서 trypsin으로 처리하여 전기영동으로 확인한 결과 가수분해 직후부터 $\beta-casein$ 위치의 band가 희미해지기 시작하고 저분자량의 band가 나타나기 시작하였으나 120분이 지난 후에는 모든 band가 가수분해되어 사라졌고 산양유에서 분리된 $\beta-casein$을 trypsin으로 처리하여 120분 경과 후 그 가수분해물을 이용하여 ACE 저해효과를 측정한 결과 가수분해하지 않은 $\beta-casein$은 $1.80\pm1.21\%$의 ACE 저해활성을 보였으나 trypsin으로 가수분해하여 ACE 저해 활성을 측정하였을 때 $25.36\pm0.79\%$의 저해 활성을 나타내었으며, trypsin에 의한 $\beta-casein$가수분해물의 $IC_{50}$을 측정한 결과 $308.7\pm2.77({\mu}g/mL)$로 나타났다.

• 한국미생물·생명공학회지
• /
• 제13권3호
• /
• pp.191-198
• /
• 1985

루우핀콩 단백질 농축물(LPC)을 이용한 두유에 7가지 유산균과 13가지 유산균 조합을 접종하여 유생성능력을 검토하고 루우핀 두유에 탄수화물 분해 효소로 처리한 것과 하지 않은 것의 차이를 살펴보았다. 그 결과, L. acidophilus, L. casei, S. lactis, L. mesenteroides, L. acidophilus와 S. thermophilus의 혼합균과 S. lactis와 L. mesenteroides의 혼합균을 선정하여 탄수화물 분해효소로 처리한 루우핀 두유와 처리하지 않은 루우핀 두유에서의 유산균의 생육과 산생성 능력을 조사하였다. 효소처리에 의한 루우핀 두유의 당조성은 처리하지 않은 루우핀 두유에 비하여 Fructose가 8.2배, Glucose가 3.0배 그리고 maltose가 2.3배였으며 총 유이당 함량은 1.5배였다. 효소처리하지 않은 루우핀 두유에서는 L., mesenteroides가 최대 생균수 1.0 $\times$ $10^{9}$ $m\ell$, 최종 pH 4.40 및 최종 산도 0.46%를 나타내어 가장 우수하였으며 효소 처리한 루우핀 두유에서는 L. acidophilus와 S. thermophilus의 혼합균이 최대 생균수 1.9 $\times$ $10^{9}$ $m\ell$, 최종 pH 3.69 및 최종 산도 1.13%를 보여주어 가장 뛰어난 유산균 조합임을 나타내었다. 유산 발효를 통한 루우핀 두유의 물리적 성질의 변화를 살펴보면 대체로 발효가 진행됨에 따라 효소처리하지 않은 루우핀 두유 기질에서는 점도가 증가하였고, 효소처리한 기질에서는 감소하는 경향을 나타내었다. 또한 발효된 루우핀 두유의 점도변화와 심전속도는 유산균에 따라 다양함을 보여주었다. 관능 검사 결과에서 효소처리한 루우핀 두유를 S. lactis 및 L. casei로 배양한 것과 S. lactis와 L. mesenteroides 및 L. acidophilus와 S. thermophilus의 혼합균으로 배양한 것이 비교적 우수한 풍미를 지녔으며 유산균 음료로서의 사용 가능성이 확인되었다.

• Journal of Nutrition and Health
• /
• 제31권3호
• /
• pp.363-368
• /
• 1998

Taurine is only supplied to the infants from the breast-fed or formula milks because the enzyme activities of taurine biosynthesis are limited in early stages of infants . The objectives of present study were to quantitate the contents of tarurine in human milk and to estimate the intake of taurine by breast-fed infants during early period of lactation. Thirty -three lactating women, volunteered and delivered in R hospital in Serou. were recruited. Milk samples were collected every day at B1-B5 day(from 1 to 5 day dafter start of milk secretion), 15th and 30th day postpartum. Taurine contents were determined by HPLC equipped with RF-detector. The intake of taurine by infants was estimated by multiplization with the infant milk intake reported in our laboratory. The content of taurine was 406$\pm$174nmol/ml at B1-B5 day, and then gradually decreased to 359$\pm$125nmol/ml at 15th day and to 304$\pm$94nmol/ml at 30th day postpartum. The estimated intake of taurine was almost same as 24-25mg/day at B1-B5 day, and 15th , 30th days postpartum . This results was due to the increase of the intake of milk by infants.

• Asian-Australasian Journal of Animal Sciences
• /
• 제23권10호
• /
• pp.1369-1379
• /
• 2010

This study investigated purification and milk-clotting activity of the enzymes produced by Bacillus subtilis var, natto and Rhizopus oligosporus compared with that of commercial rennet. The clotting time, viscosity, tension and microstructure of the curd and electrophoretic patterns of milk proteins were determined. The milk-clotting activity/proteolytic activity ratios (MCA/PA ratio) of B. subtilis, R. oligosporus and commercial rennet were also compared. The results revealed that the curd formed by the commercial rennet had the highest viscosity and curd tension and the shortest clotting time among the three enzymes. However, curd produced by Rhizopus enzymes was ranked as second. From the MCA/PA ratio and electrophoretogram analyses it could be concluded that the enzyme produced by B. subtilis had the highest proteolytic activity, while the commercial rennet had the highest milk-clotting activity. Observations of microstructures of SEM showed that the three-dimensional network for curd formed by commercial rennet was denser, firmer and more smooth. The milk-clotting activity, specific activity, purification ratio and recovery of the purified enzymes produced by both the tested organisms were also determined with ion exchange chromatography and gel filtration.

• Asian-Australasian Journal of Animal Sciences
• /
• 제9권3호
• /
• pp.299-302
• /
• 1996

Milk samples(n = 78) were taken 19d, 20d, 21d, 22d after artificial insemination(AI) for early pregnancy diagnosis by using the Enzyme immunoassay(EIA) kit. The progesterone ($P_4$) concentration in the whole milk was measured on the same day of pregnancy diagnosis. Rectal palpation(RP) was accomplished between 60d and 70d after AI to estimate the ovary condition and pregnancy status. Milk progesterone concentrations measured by Radio-immunoassay(RIA) method, in the pregnant cows at 17d, 19d, 21d after insemination were $17.10{\pm}0.91$, $17.60{\pm}0.46$, and $18.43{\pm}0.79nmol/l$, whereas those in the not-pregnant cows were $6.57{\pm}1.03$, $2.63{\pm}0.29$, and $0.67{\pm}0.08nmol/l$, respectively. When the progesterone concentration was less than 7 nmol/l, the color of the EIA kit was lighter and when the progesterone concentration was ${\geq}16nmol/l$, the color of the EIA kit was darker compared to the standard color. The detection rates of error by judging the color differences were 5.1% and 20.7%, respectively. In the early pregnancy diagnosis by the EIA kit and RIA method, the accuracy rates in the pregnancy of cows were 82% and 87%, and those in not-pregnant cows were 86% and 91%, respectively. For ovarian status estimated by the RIA method and certified by RP, the accuracy rates of the ovarian atrophy, follicular cyst and luteal cyst were 80, 91 and 83% and the progesterone concentrations were 2.51, 2.03, and 26.7 nmol/l, respectively.