• 한국미생물·생명공학회지
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• 제1권2호
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• pp.99-104
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• 1973

A study on the active center of the acid protease from Penicillium sp. was conducted, and also the milk clotting activity of acid prorease was measured. 1. PCMB failed to influence the proteolytic activity of acid protease, indicating that a reactive sulfhydryl group is not required for the enzymatic activity. 2. $\varepsilon$-amino caproic acid did not show any inhibitory effect on tile proteolytic activity of acid protease. 3. Also 2, 4-dinitro phenol did not show any inhibitory effect on the enzyme activity. 4. Acid protease from Penicillium sp. showed a strong milk clotting activity in the presence of Ca ion. 5. This enzyme had a strong proteolytic activity on various substrate, such as casein, denatured hemoglobin, ovalbumin, denatured bovine muscle protein, denatured percine muscle protein and denatured chicken muscle protein.

• Journal of Dairy Science and Biotechnology
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• 제30권2호
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• pp.119-129
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• 2012

Lactic acid bacteria (LAB) have been used as starter cultures in the manufacturing processes of fermented dairy products such as cheese and yogurt. LAB have a proteolytic system to use the nitrogen source from milk for their growth. The proteolytic system involved in casein utilization provides cells with essential amino acids during growth in milk and is also of industrial importance, because of its contribution to the development of the organoleptic properties such as flavor of fermented milk products. In the most extensively studied LAB, Lactococcus lactis, the main features of the proteolytic system comprise 3 groups. The first is proteinase, which initially cleaves the milk protein to peptides. The second group consists of transport systems for the internalization of oligopeptides, which are involved in the cellular uptake of small peptides and amino acids. The third group, peptidases in the cell, cleaves peptides into smaller peptides and amino acids. This review is to provide the information about the proteolytic system of LAB.

• Journal of Animal Science and Technology
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• 제46권1호
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• pp.77-82
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• 2004

본 연구는 우유의 angiogenin(ANG) 생리활성기능을 조사하기 위한 전단계로 ANG 정제 방법을 확립하기 위하여 실시하였다. 우유로부터 ANG을 CM-Sepharose ion exchange chromatography, HPLC, Gel-filtration의 3단계 방법을 이용하여 정제하였다. 1단계인 CM-Sepharose ion exchange chromatography를 수행 한 결과 0.6 M NaCl 농도의 36번 분획에서 ANG의 밴드를 볼 수 있었고 2단계인 Mono-S 컬럼을 이용하여 HPLC를 수행한 결과에서는 1.0 M에서 하나의 peak가 분리되었고 전기영동 결과는 LF와 ANG 두 가지 성분이 함유되어 있음을 확인하였다. 마지막 단계인 Gel-filtration을 수행한 결과 ANG이 단일 밴드로 분리되었다. 우유 10 $\ell$로부터 약 80 ${\mu}\ell$의 ANG를 얻었고 정제된 ANG을 N-말단 아미노산 배열을 분석한 결과 AQDDYRYIHFLTQHY로 밝혀졌다.

• 한국유기농업학회지
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• 제24권4호
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• pp.957-967
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• 2016

The present study was conducted to investigate effect of dietary protected amino acid on milk yield and composition in dairy cow using meta-analysis. Total 21 research papers were employed in analysis, and mixed model was used for the analysis of effects. Effect of protected methionine (PM) and combination of protected methionine and lysine (PML) were investigated under two different levels of dietary crude protein (CP, <18% and >18%). For performance of dairy cow, milk yield, milk composition including milk fat and protein content and yield and 4% FCM (fat corrected milk) production were used for analysis. In case of milk yield, a trend of increment was found at PM supplementation at low CP (P=0.055). However, the effect of PM at high CP was detected as not significant (P>0.05). In case of milk protein, inclusion of PM at low CP showed significant decrement (P<0.05). However, there was no significant effect of MP on milk protein at high CP (P>0.05). Supplementation of MP at high CP level showed significant increment of milk fat (P<0.05). MP supplementation represented significant increment of 4% FCM production (P<0.05) regardless of dietary CP levels. Effects of PML on milk yield and composition at both of low and high dietary CP were not significant in this study. However, it seem to be that there was a possible positive effect of MPL application at high dietary CP on performance of dairy cow.

• 한국식품영양과학회지
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• 제28권1호
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• pp.9-15
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• 1999

Taurine contents in alcoholic and non alcoholic beverages, milk and milk products, sugars and condiments were determined for 83 food items commonly used by Koreans. Taurine concentrations of food samples were analyzed by using an automated amino acid analyzer(Biochrom 20, Pharmacia LKB) based on ion exchange chromatography. Taurine was not detected in most carbonated beverages, but found in a variety of fruit and vegetable beverages(canned) in the range of 0.13 ~1.43mg taurine/ 100g wt, and in instant coffee or tea beverages(canned) in the range of 0.10~0.41mg taurine/100g wt. The traditional Korean turbid rice wine(takju) sample contained the highest level of taurine (2.29mg/100g wt) among alcoholic beverages tested, which was followed by wine(0.59~0.88mg tau rine/100g wt) and beer(0.53~0.73mg taurine/100g wt). Ordinary milk samples contained 1.05~1.40 mg taurine/100g wt, and a variety of taurine supplemented infant formulas manufactured by Korean companies included 17.3~25.4mg taurine/100g wt. Taurine was not detected in most sugars and sweetners except a couple of chocolate samples(2.13~2.18mg taurine/100g wt). Exceptionally high level of taurine was found in a curry powder sample(16.9mg taurine/100g wt), while the rest of commonly used condiments contained less than 2.90mg taurine/100g wt.

• 한국관광식음료학회:학술대회논문집
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• 한국관광식음료학회 2003년도 학술논문발표집
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• pp.19-35
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• 2003

This study was carried out to find a cholesterol removal rate, flavor development, and bitter amino acid productions in Cheddar cheese treated with -cyclodextrin (${\beta}-CD$): 1) Control (no homogenization, no ${\beta}--CD$), and 2) Milk treatment (1000 psi milk homogenization, 1% ${\beta}-CD$). The cholesterol removal of the cheese were 79.3%. The production of short-chain free fatty acids (FFA) increased with a ripening time in both control and milk treated cheese. The releasing quantity of short-chain FFA was higher din milk treated cheese than control at 5 and 7 mo ripening. Not much difference was found in neutral volatile compounds production between samples. In bitter-tasted amino acids, milk treatment group produced much higher than control. In sensory analysis, texture score of control Cheddar cheese significantly increased, however, that in cholesterol-reduced cheese decreased dramatically with ripening time.

• Journal of Dairy Science and Biotechnology
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• 제17권1호
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• pp.16-31
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• 1999

Milk and milk products, especially the cow's milk and cheese, have been used since the ancient time. Because they contains almost all kinds of nutrients that are necessary for human beings except for iron, n-3 fatty acid, and vitamin C. Milk is an excellent dietary source of protein, calcium and phosphorus. The biological value of milk protein is as high as those of red meat and eggs. So cheese, a food processed from concentrated milk protein, is highly recommended food for the patient of diabetes mellitus. Because the major form of milk lipids is n-6 fatty acid, milk and milk products may not be a good food for the patients of cardiovascular disease. But the nutritional quality of milk lipids cannot be inferior to those of margarine, fish oil, and vegetable oil. Milk has been produced commercially since 1936 in Korea. The most popular milk product is a drink milk now in Korea. But according to the change of dietary pattern the consumption of yoghurt and cheese has been enormously increased during the last 20 years. As the soy sauce, tofu, and soy been paste have been the fundamental seasoning and source of protein in Korea, milk and cheese have consisted the essential flavor of western cuisine. But the basic idea for the usage of protein, peptides, and amino acids are the same. We found that milk and milk products can be nicely added in many Korean dishes such as Juk, Mandoo, Jeon, and Bindeatuk for the diversity of traditional flavor.

• Asian-Australasian Journal of Animal Sciences
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• 제27권12호
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• pp.1705-1711
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• 2014

The objective of this study was to evaluate the effect of ruminally protected amino acids (RPAAs) and ruminally protected fat (RPF) supplementation on ruminal fermentation characteristics (in vitro) and milk yield and milk composition (in vivo). Fourteen mid-lactating Holstein dairy cows (mean weight $653{\pm}62.59kg$) were divided into two groups according to mean milk yield and number of days of postpartum. The cows were then fed a basal diet during adaptation (2 wk) and experimental diets during the treatment period (6 wk). Dietary treatments were i) a basal diet (control) and ii) basal diet containing 50 g of RPAAs (lysine and methionine, 3:1 ratio) and 50 g of RPF. In rumen fermentation trail (in vitro), RPAAs and RPF supplementation had no influence on the ruminal pH, dry matter digestibility, total volatile fatty acid production and ammonia-N concentration. In feeding trial (in vivo), milk yield (p<0.001), 4% fat corrected milk (p<0.05), milk fat (p<0.05), milk protein (p<0.001), and milk urea nitrogen (p<0.05) were greater in cows fed RPAAs and RPF than the corresponding values in the control group. With an index against as 0%, the rates of decrease in milk yield and milk protein were lower in RPAAs and RPF treated diet than those of basal diet group (p<0.05). In conclusion, diet supplemented with RPAAs and RPF can improve milk yield and milk composition without negatively affecting ruminal functions in Holstein dairy cows at mid-lactating.

• 생약학회지
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• 제29권4호
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• pp.360-364
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• 1998

To develop new elicitors inducing the high productivity of taxane derivatives, plant growth inhibitors, namely, maleic acid hydrazide, N-phosphomethyl glycine and succinic acid 2.2-dimethyl hydrazide, coconut milk and yeast extract were administrated in the cell suspension culture system of Taxus cuspidata, and the production of baccatin III were analysed. The effects of amino acid related with the biosynthesis of baccatin III were also examined in these culture system. As the results, a remarkable enhancement of baccatin III production was observed in the cultivation with coconut water and with maleic acid hydrazide.

• 한국축산식품학회지
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• 제33권4호
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• pp.542-548
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• 2013

살균한 원유에 지방분해효소와 단백질 분해효소활성이 가장 높게 나타났던 균주를 접종하고 저장하면서 내냉성미생물이 생성하는 효소가 원유의 품질에 미치는 영향을 조사하였다. 지방분해효소활성이 높은 Acinetobacter genomospecies 10은 냉장저장기간 중 총 고형분과 유지방의 함량에 영향을 미치지 않았고, 지방의 분해는 냉장보관 14일째에 대조구와 비교하여 2.6배 이상의 유리지방산을 생성하였다. 생성된 지방산의 조성은 short chain free fatty acid(SCFFA), middle chain free fatty acid(MCFFA) 및 long chain free fatty acid(LCFFA)를 모두 생성하였으며, 특히 SCFFA와 MCFFA의 증가율이 높았다. 단백질 분해효소활성이 높은 Serratia liquefaciens은 원유의 총 고형분과 유단백질 함량에 영향을 미치지 않았고, 단백질 조성의 변화는 냉장저장기간 동안 케이신의 함량이 서서히 감소하다가 10일째부터 $\kappa$-케이신의 함량이 현저히 감소하였다. 유리아미노산은 대조구와 비교하여 냉장저장 14일째 2.8배 이상 생성되었으며 특히 소수성 아미노산으로 쓴맛을 내는 leucin, valine 등의 함량이 급격히 증가하였다.