• Title/Summary/Keyword: dairy products

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The Effects of Milking Time and Dairy Processes on Melatonin Contents in Milk (착유 시간 및 유처리 공정이 우유 내 멜라토닌 함량에 미치는 영향)

  • Kang, S.H.;Baick, S.C.
    • Journal of Dairy Science and Biotechnology
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    • v.26 no.1
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    • pp.1-4
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    • 2008
  • Melatonin is one of the functional hormones in the milk and found in all mammalian species. The primary motivation for the use of melatonin as a supplement is as a natural aid to better sleep. Melatonin contents in milk vary according to the naturally occurring factors such as seasons and milking times. As a number of studies indicate melatonin supplementation helps to reduce the age-related decline in hormone production and overall enhancement of health, the more detailed studies are required to know the nature of milk derived hormones and to clarify them as a functional value adaptation. The objectives of this study were to examine the change of melatonin content in bovine milk during different milking times at the two dairy farms and during dairy process including homogenization and pasteurization. Commercial dairy products including night time milking products(night milk) marketed in Japan were also investigated. Melatonin content was determined by radioimmunoassay using 125I. Individual milk was collected from lactating Holstein cows at Kyong-Ki province in Korea. At farm A, the melatonin contents milking at 4 a.m. was higher than those of 7 p.m. and 12 p.m.($6.90{\pm}3.55,\;2.01{\pm}1.47$ and $0.16{\pm}0.04pg/mL$, respectively). At farm B, the mean melatonin contents milked from 24:00 AM to 05:00 AM have shown the highest contents ($4.65{\pm}$0.72pg/mL), and milking samples of the rest time had very little or non-detection of melatonin contents. Melatonin contents of commercial night milk samples were about 5 times higher than those of other common milk products. These results suggested that melatonin might be heat-resistant and commercial dairy process might not affect its contents in the final products.

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Determination of the Authenticity of Dairy Products on the Basis of Fatty Acids and Triacylglycerols Content using GC Analysis

  • Park, Jung-Min;Kim, Na-Kyeong;Yang, Cheul-Young;Moon, Kyong-Whan;Kim, Jin-Man
    • Food Science of Animal Resources
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    • v.34 no.3
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    • pp.316-324
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    • 2014
  • Milk fat is an important food component, and plays a significant role in the economics, functional nutrition, and chemical properties of dairy products. Dairy products also contain nutritional resources and essential fatty acids (FAs). Because of the increasing demand for dairy products, milk fat is a common target in economic fraud. Specifically, milk fat is often replaced with cheaper or readily available vegetable oils or animal fats. In this study, a method for the discrimination of milk fat was developed, using FAs profiles, and triacylglycerols (TGs) profiles. A total of 11 samples were evaluated: four milk fats (MK), four vegetable oils (VG), two pork lards (PL), and one beef tallow (BT). Gas chromathgraphy analysis were performed, to monitor the FAs content and TGs composition in MK, VG, PL, and BT. The result showed that qualitative determination of the MK of samples adulterated with different vegetable oils and animal fats was possible by a visual comparision of FAs, using C14:0, C16:0, C18:1n9c, C18:0, and C18:2n6c, and of TGs, using C36, C38, C40, C50, C52, and C54 profiles. Overall, the objective of this study was to evaluate the potential of the use of FAs and TGs in the detection of adulterated milk fat, and accordingly characterize the samples by the adulterant oil source, and level of adulteration. Also, based on this preliminary investigation, the usefulness of this approach could be tested for other oils in the future.