Grasslands Research Centre, AgResearch Ltd., Palmerston North 4442, New Zealand; School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150090, China.
Grasslands Research Centre, AgResearch Ltd., Palmerston North 4442, New Zealand.
Food Chem. 2018 Sep 15;260:327-335. doi: 10.1016/j.foodchem.2018.04.011. Epub 2018 Apr 6.
4-alkyl-branched-chain fatty acids (vBCFAs) are responsible for the goaty-sheepy flavour of sheep and goat milk. The levels of vBCFAs were investigated in sheep, goat and cow milk powders. The effect of season and industrial processes on the levels of vBCFAs in sheep milk was also evaluated. Sheep milk powders contained lower amounts of 4-Me-8:0 and 4-Et-8:0 (143-176 and 1.2-10.7 µg/g milk fat) than goat milk powders (335-481 and 73.1-105 µg/g milk fat), while 4-Me-9:0 was low in both sheep and goat milk powders (<8 µg/g milk fat). Odour activity values (OAVs) of sheep milk powders (17-393) were 6-fold lower than the values of goat milk powders (882-1323). Higher levels of vBCFAs were found in sheep milk produced in spring than in summer. Thermisation had little impact on vBCFAs; however, spray drying led to dramatic increases in free vBCFAs, particularly towards late lactation, which resulted in higher OAVs in sheep milk powder compared to raw milk.
4-支链脂肪酸（vBCFAs）是导致羊奶和牛奶具有羊膻味的原因。本研究调查了绵羊奶、山羊奶和牛奶粉中的 vBCFA 水平，并评估了季节和工业加工对绵羊奶中 vBCFA 水平的影响。绵羊奶粉中的 4-Me-8:0 和 4-Et-8:0（143-176 和 1.2-10.7μg/g 乳脂）含量低于山羊奶粉（335-481 和 73.1-105μg/g 乳脂），而 4-Me-9:0 在绵羊奶和山羊奶粉中含量均较低（<8μg/g 乳脂）。绵羊奶粉的气味活度值（OAV）为 17-393，是山羊奶粉（882-1323）的 6 倍。春季生产的绵羊奶中 vBCFA 含量较高，夏季生产的绵羊奶中 vBCFA 含量较低。巴氏杀菌对 vBCFA 的影响较小；然而，喷雾干燥会导致游离 vBCFA 急剧增加，尤其是在泌乳后期，这导致绵羊奶粉的 OAV 高于生奶。
