Biosciences Research, Agriculture Victoria, AgriBio, 5 Ring Road, Bundoora, Victoria 3083, Australia.
CSIRO Agriculture and Food, Werribee, Victoria 3030, Australia.
Food Chem. 2017 Dec 15;237:865-869. doi: 10.1016/j.foodchem.2017.06.038. Epub 2017 Jun 8.
Seasonal change of milk composition could offer opportunities for dairy manufacturers. A systematic survey on seasonal variation of six classes of polar lipids was conducted with 19 Holstein cows over the entire milking season using liquid chromatography-mass spectrometry technique. This study revealed that most polar lipid classes were positively correlated with the total fat content, but negatively correlated with fat globule size. All polar lipid classes displayed a large cow-to-cow variation as well as seasonal variation. All of the six classes showed a gradual increase over the milking season with the highest concentration observed in May (autumn). However, the proportion of different polar lipid classes remained constant during the entire milking season. This finding suggests that the production of polar lipids is highly regulated in the mammary gland. The implication of such a seasonal variation of polar lipids in the nutritional and technological aspects of milk is discussed.
奶成分的季节性变化为乳制品制造商提供了机会。本研究采用液相色谱-质谱联用技术，对 19 头荷斯坦奶牛整个泌乳期内 6 类极性脂的季节性变化进行了系统调查。结果表明，大多数极性脂类与总脂肪含量呈正相关，与脂肪球大小呈负相关。所有极性脂类在牛群间和季节间均存在较大变异。6 类极性脂在泌乳期内逐渐增加，5 月（秋季）浓度最高。然而，不同极性脂类的比例在整个泌乳期内保持不变。这表明极性脂的合成在乳腺中受到高度调控。讨论了这种极性脂季节性变化在牛奶营养和技术方面的意义。
