708. Phospholipids in New Zealand dairy products: II. Seasonal variations in the phospholipid content of butter and of milk and cream

Abstract

Samples of milk, skim-milk and raw cream from one factory and of pasteurized cream, buttermilk and butter from two factories were taken twice monthly for varying periods for estimation of total phospholipids and (in butter only) of lecithin, cephalin and sphingomyelin.Seasonal variations in the phospholipid contents of milk, skim-milk and raw cream over 13 months probably were due to the greater proportion of small fat globules in autumn (late lactation) milk compared with spring (early lactation) milk.There were regularly recurring seasonal variations in total phospholipid content of the butters over 3 years. Maximum results were found during autumn and minimum results in winter. Lecithin, cephalin and sphingomyelin contents followed the same trends as the total phospholipid contents.Seasonal variations in phospholipid contents of buttermilks and butters were due mainly to variations in the amount of phospholipid per unit of fat in the cream. Differences in butter-making technique had little effect on the proportion of phospholipids from the cream retained in the butter.Average results for total phospholipid content of the products examined were: milk, 0·038% (0·031–0·050%); skim-milk, 0·018% (0·014–0·023%); buttermilk, 0·156% (0·103–0·191%); butter, 0·133% (0·099–0·181%). The average result for percentage of total phospholipid in the fat of the raw creams examined was 0·44% (0·38–0·51%); and in the fat of the pasteurized creams 0·41% (0·35–0·49%). Average weighted results for total phospholipid and for lecithin, cephalin and sphingomyelin contents of butter were 0·139, 0·041, 0·051 and 0·047% respectively.