Native milk fat globule size and its influence on the natural creaming properties of buffalo milk

Abstract

We investigated the influence of the physical characteristics of fat globules on the creaming properties of buffalo milk and on the fatty acid profile of the various fractions separated by natural creaming. A total of six bulk buffalo milk samples were taken from one individual farm in central Italy. An aliquot of each fresh raw milk sample underwent gravity separation and three fractions were separately collected: the bottom, middle, and top. The top and medium fractions showed a significantly (P<0.01) higher average diameter of the milk fat globules and a higher percentage of large globules. The top fraction was also made up of more densely packed globules as revealed by the higher (P<0.01) number of globules per ml. The smallest globules however tended to remain in emulsion, by virtue of the greater amount of membrane per unit volume, which makes them compatible with the aqueous phase. As a result the highest percentages of small globules were found in the bottom phase. The creaming capacity of buffalo milk was lower compared to cow milk. Despite the higher contribution of lipids in the top fraction, there were more fatty acids that are considered beneficial to human health, such as C18:0 (P<0.01), C18:2 cis9, 12; C18:2 cis9, t11 (rumenic acid) and C20:3 n6. In conclusion, natural creaming can act on the quality of the products by selecting globules with different diameters and nutritional quality, thus increasing the nutritional value of dairy products.