Buttermilk lipids

The fat obtained by different methods of processing varies in composition and therefore in properties (Table 4.12 Mulder and Walstra 1974). For example, the amount of phospholipid per 100 g of fat is much greater in buttermilk from 40% cream than in whole milk (21.6 vs. 0.9 g), and these phospholipids contain much more unsaturated fatty acids than the whole milk lipids. 

The diets used in these initial studies on the effect of consuming buttermilk on serum cholesterol were not standardized, and involved a small number of individuals. Hussi et al. (1981) fed a large group of healthy volunteers with either 2.7 L/day of skim milk or 2 L/day of buttermilk or a control diet for three weeks. All diets were standardized for macronutrient and energy level, and all volunteers consumed the control diet for 3 weeks prior to the study. No significant differences were found in the serum lipid or lipoprotein profiles between the control and test groups. 

Improvement of membrane separation technology has resulted in the isolation of MFGM-enriched material from commercially available products. A phospholipid-rich fraction can be extracted from whey (Boyd et al., 1999) and buttermilk (Sachedva and Buchheim, 1997) with a reported yield of 0.25 g of phospholipids/g of protein in buttermilk (Sachdeva and Buchheim, 1997). Microfiltration of whey derived from the Cheddar cheese process, using 0.2 pm ceramic filters results in a fraction containing two major phospholipids, phosphatidylcholine and phosphatidylethanolamine, and lesser amounts of phosphatidylinositol, phosphatidylserine, sphingomyelin and cerebrosides (Boyd et al., 1999). The phospholipid fraction separated from the total lipids contains a larger proportion of mono- and polyunsaturated fatty acids (mainly oleic, Cig i and linoleic, C ) compared to the total lipid and the neutral lipid fraction (Boyd et al., 1999). 

Astaire, J.C., Ward, R., German, J.B., Jimenez-Flores, R. 2003. Concentration of polar MFGM lipids from buttermilk by microfiltration and supercritical fluid extraction../ Dairy Sci. 86, 2297-2307. 

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