• 한국축산식품학회지
• /
• 제36권2호
• /
• pp.206-214
• /
• 2016

The aim of this study was to evaluate the potential use of fatty acids, triacylglycerols, and cholesterol in the detection of adulterated milk fat. The fatty acid, triacylglycerol, and cholesterol profiles of the mixtures of milk and non-milk fat (adulteration ratios of 10%, 30%, 50%, 70%, and 90%) were analyzed by gas chromatography. The results showed that concentrations of the fatty acids with oleic acid (C18:1n9c) and linoleic acid (C18:2n6c), triglycerides with C52 and C54, and cholesterol detected are proportional to the adulteration ratios remarkably. Oleic acid (C18:1n9c), linoleic acid (C18:2n6c), C52, and C54 were lower in pure milk fat than in adulterated mixtures. In contrast, pure milk has a higher cholesterol concentration than all adulterated mixtures (adulteration concentration in the range 10-90%). Thus, we suggest that oleic acid (C18:1n9c), linoleic acid (C18:2n6c), C52, C54, and cholesterol are suitable indicators and can be used as biomarkers to rapidly detect adulterated milk fat by gas chromatography. This study is expected to provide basic data for adulteration and material usage. Moreover, this new approach can detect the presence of foreign oils and fats in the milk fat of cheese and can find application in related studies.

• 한국식생활문화학회지
• /
• 제14권4호
• /
• pp.361-369
• /
• 1999

The purpose of this study is to investigate the current situation of children's milk intake at home and school in order to identify the better way to help children's milk intake. For this, 895 elementary students participated in this study through the questionnaire developed by researchers. Conclusions drawn from the results of this study are as follows : 1. Various kinds of milk should be provided for children both at home and school so that they can choose an appropriate milk for themselves. 2. Teachers at school should help children's milk intake not through forcing them but through appropriate educational approach. 3. Milk distribution system and ways of refrigeration of milk in school should be improved. 4. Nutrition education should be implemented for children so that they themselves choose milk as favorite beverage.

• Journal of Dairy Science and Biotechnology
• /
• 제35권1호
• /
• pp.55-72
• /
• 2017

The second article of 'Effects of heat treatment on the nutritional quality of milk,' titled 'Destruction of microorganisms in milk by heat treatment' and authored by Dr. Seong Kwan Cha, who worked at the Korea Food Research Institute, covers the heat-stable microorganisms that exist in milk after pasteurization. The article focusses on the microbiological quality of raw milk and market milk following heat treatment, and is divided into four sub-topics: microbiological quality of raw milk, survey and measurement of microorganisms killed in raw milk, effect on psychrophilic and mesophilic microorganisms, and effect of heat treatment methods on thermoduric microorganisms. Bacillus spp. and Clostridium spp. are sporeforming gram-positive organisms commonly found in soil, vegetables, grains, and raw and pasteurized milk that can survive most food processing methods. Since spores cannot be inactivated by LTLT (low temperature long time) or HTST (high temperature short time) milk pasteurization methods, they are often responsible for food poisoning. However, UHT (ultra high temperature) processing completely kills the spores in raw milk by heating it to temperatures above $130^{\circ}C$ for a few seconds, and thus, the UHT method is popularly used for milk processing worldwide.

• 한국축산식품학회지
• /
• 제35권2호
• /
• pp.205-210
• /
• 2015

The objective of this study was to develop yogurt-cheese using cow’s milk, ultrafiltrated cow’s milk, and soy milk. The addition of soy milk and ultrafiltrated milk increased the amount of protein in the yogurt-cheese. Yogurt-cheeses were made using cheese base using 10% and 20% soy milk with raw and ultrafiltrated cow’s milk, and stored at 4°C during 2 wk. The yield of yogurt-cheeses made with added soy milk was decreased and the cutting point was delayed compared to yogurt-cheese made without soy milk. Yogurt-cheese made using ultrafiltrated cow’s milk showed the highest yield. However, yogurt-cheese made with added soy milk had higher protein content and titratable acidity than yogurt-cheese made using raw and ultrafiltrated cow’s milk. Fat and lactose contents in the yogurt-cheese made with added soy milk were lower. Yogurt-cheeses made with added soy milk contained several soy protein bands corresponding to the sizes of α₂-, β-, and κ-casein band. Yogurt-cheese made with added soy milk had similar elasticity to yogurt-cheese made without soy milk but had lower cohesiveness. There was no significant difference in the number of lactic acid bacteria in the different cheeses, as all had over 8.0 Log CFU/g. Considering these data and the fact that proteins and fats of vegetable origin with high biological value were observed as well as unsaturated fats, yogurt-cheese made with added soy milk can be considered to be a functional food.

• Journal of Dairy Science and Biotechnology
• /
• 제15권1호
• /
• pp.45-51
• /
• 1997

Korea dairy industry is placed on the very critical situation with the progression of free trade marketing system internationally. The sterilized milk or pasteurized extended shelf life milk can be considered as the international trade dairy products. Now all dairy foods would be selling in international market. To keep and improve our dairy foods market, the Korea dairy system improvement committee was inaugurated in 1995. This committee has done so many works to improve or dairy system such as the settlement of raw milk supply and demand, centralization of raw milk collection, ideal raw milk price system and dairy foods marketing structure, etc.

• Molecules and Cells
• /
• 제39권5호
• /
• pp.410-417
• /
• 2016

During the lactation cycle of the bovine mammary gland, autophagy is induced in bovine mammary epithelial cells (BMECs) as a cellular homeostasis and survival mechanism. Interferon gamma ($IFN-{\gamma}$) is an important antiproliferative and apoptogenic factor that has been shown to induce autophagy in multiple cell lines in vitro. However, it remains unclear whether $IFN-{\gamma}$ can induce autophagy and whether autophagy affects milk synthesis in BMECs. To understand whether $IFN-{\gamma}$ affects milk synthesis, we isolated and purified primary BMECs and investigated the effect of $IFN-{\gamma}$ on milk synthesis in primary BMECs in vitro. The results showed that $IFN-{\gamma}$ significantly inhibits milk synthesis and that autophagy was clearly induced in primary BMECs in vitro within 24 h. Interestingly, autophagy was observed following $IFN-{\gamma}$ treatment, and the inhibition of autophagy can improve milk protein and milk fat synthesis. Conversely, upregulation of autophagy decreased milk synthesis. Furthermore, mechanistic analysis confirmed that $IFN-{\gamma}$ mediated autophagy by depleting arginine and inhibiting the general control nonderepressible-2 kinase (GCN2)/eukaryotic initiation factor $2{\alpha}$ ($eIF2{\alpha}$) signaling pathway in BMECs. Then, it was found that arginine supplementation could attenuate $IFN-{\gamma}$-induced autophagy and recover milk synthesis to some extent. These findings may not only provide a novel measure for preventing the $IFN-{\gamma}$-induced decrease in milk quality but also a useful therapeutic approach for $IFN-{\gamma}$-associated breast diseases in other animals and humans.

• Asian-Australasian Journal of Animal Sciences
• /
• 제31권10호
• /
• pp.1542-1549
• /
• 2018

Objective: Because lactation periods in dairy cows lengthen with increasing total milk production, it is important to predict individual productivities after 305 days in milk (DIM) to determine the optimal lactation period. We therefore examined whether the random regression (RR) coefficient from 306 to 450 DIM (M2) can be predicted from those during the first 305 DIM (M1) by using a RR model. Methods: We analyzed test-day milk records from 85,690 Holstein cows in their first lactations and 131,727 cows in their later (second to fifth) lactations. Data in M1 and M2 were analyzed separately by using different single-trait RR animal models. We then performed a multiple regression analysis of the RR coefficients of M2 on those of M1 during the first and later lactations. Results: The first-order Legendre polynomials were practical covariates of RR for the milk yields of M2. All RR coefficients for the additive genetic (AG) effect and the intercept for the permanent environmental (PE) effect of M2 had moderate to strong correlations with the intercept for the AG effect of M1. The coefficients of determination for multiple regression of the combined intercepts for the AG and PE effects of M2 on the coefficients for the AG effect of M1 were moderate to high. The daily milk yields of M2 predicted by using the RR coefficients for the AG effect of M1 were highly correlated with those obtained by using the coefficients of M2. Conclusion: Milk production after 305 DIM can be predicted by using the RR coefficient estimates of the AG effect during the first 305 DIM.

• 한국초지조사료학회지
• /
• 제14권1호
• /
• pp.57-63
• /
• 1994

We use a variety of methods to determine the optimum time for havesting corn for silage. In addition, adequate dry matter for silage must be considered along with maturity stage. The objective of this study was to evaluate using the kernel milk line to determine when to harvest com for silage in 1992 on the Livestock Experimental F m , Keiymung Junior College at Keongsan, Keongsangbukdo. Four hybrids were field grown and com plants were harvested at various stages of kernel development so that kemel milk line movement could be analyzed whilc the corn was in the premature stages. As the plants approached maturity, the ears were collected from each of the hybrids and the position of the milk line wa5 noted. Then the whole plants were chopped and the content of DM was determined. The milk line was a readily identifiable feature of maturing com kemels. We focused on the five development \tage\. The fint was "soft dough". The second was "dent". The third wa, "75% milk". and the fourth wa5 "half milk". The half milk occurs when the milk line is positioned falf way down the kemel face. and the final stages win "no milk", milk disappearance as indicators of physiological maturity in maix. Milk free stage of the kemel occurred from I to 3 days prior to black layer having developed. The range for harvesting com for silage occurs a kemels mature from 75% milk to no milk. Position of milk line was easy to see. and can be used as a visible indicator to determine com matunty stage\ and whole plant dry matter. Whole plant dry matter increased with advancing maturity. averaged over hybrids it was 24.1, 25.6. 28.5. 34.6 and 39.0% at soft dough, dent, 75% milk. half milk and no milk. Milk line was more usehl indicator in monitoring corn maturity prior to physiological maturity.ing corn maturity prior to physiological maturity.

• Journal of Dairy Science and Biotechnology
• /
• 제17권1호
• /
• pp.50-57
• /
• 1999

Milk is a first food for as long as the mammalian race has existed. A characteristic unique to mammal is their ability to secrete milk as a source of nutrients and immunological protection for their young. From a nutitrional viewpoint, milk has heen described as nature's most perfect food, owing mainly to its biological role as the only source of nutrition for the infant mammal. Milk is estimated to contain more than 100,000 molecular species, However, the average contents of milk can be simplified to 3.4% fat, 3.1% protein (80% casein protein and 20% whey protein), 4.5% lactose, and 0.7% ash. Chemically, milk is a very complex fluid rich in nutrients, antibodies, growth factors, antimicrobial components etc. This report will discuss functional properties of milk components, such as lactoferrin, opoid peptide, CPP, cGMP and sialic acid etc.

• Journal of Dairy Science and Biotechnology
• /
• 제22권2호
• /
• pp.113-118
• /
• 2004

가열유는 rennet 응고성, 전자현미경법, -SH기정량, 전기영동적 관찰법, 340nm에서 흡광도 측정법 등 여러 가지 방법에 의하여 판정이 가능하나 간편성, 신속성으로 보아 rennet 응고성 이용이 가장 돌출하다. 70도 이상의 가열유는 rennet 응고성을 이용하여 판정이 가능하다. 앞으로 $55^{\circ}C$ 부근의 예열 수준도 검출할 수 있는 방법이 더 개발되어야 한다.