the fatty substance of milk from which butter is made
butterfat详细解释
but.ter.fat n.（名词）The natural fat of milk from which butter is made, consisting largely of the glycerides of oleic, stearic, and palmitic acids.乳脂：牛奶中的天然脂肪，是奶油的成分之一，主要由含有油酸、硬脂酸和软脂酸的甘油脂混合物构成
