凍結乳に関する研究-3-バターミルクの凍結保存〔英文〕

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Buttermilk and buttermilk-like-fluid prepared by churning from raw cream and washed cream, respectively, were frozen and stored for various periods up to 6 months at -17°C.The amount of the precipitate (or pellet) separated from frozen-thawed buttermilk by centrifugation (1300 G, 10min) was yery small in the case of a short-term storage for 60 days or less, and chromatographically similar to casein. The ratio of phosphorus to nitrogen of the precipitate, however, increased definitely with the progress of the storage period. About 3.6g of dry matter was isolated as precipitate from 100ml of the buttermilk prepared from 35% cream and frozen for 6 months. The dry matter mostly consisted of lipid and protein in the ratio of 1: 2 to 1: 4 depending on the acidity of the original buttermilk. The lipid moiety on the average contained 14% of phospholipid.Column chromatography of the frozen material on TEAE-cellulose revealed that the preci-pitate separated from the buttermilk frozen for 100 days consisted of two major peaks. The first peak was comparable to the main component of the buttermilk-like fluid and considered to be lipoprotein derived from fat globules. The second peak was similar to α-casein in respect to the eluted position and phosphorus content.The role of lipoprotein in the frozen storage of cream as well as buttermilk was discussed.
公益社団法人日本畜産学会の論文