Seasonal variation in the triacyglycerides of bovine milk fat

Abstract

Using Gas Chromatography (GLC), the content of triacylglycerides of milk fat was determined in samples of raw milk collected monthy during one year (from june 1998 to May 1999) at milk tank level from six industries located in the VIII ^th, IX^th and X^th Region.
The triacylglycerides of pure milk fat were classified according to their chain length: short chain from C26 to C32, medium and long chain from C34 to C42 and C44 to C54 respectively. At chain level (short, medium and long) no seasonal effect was detected (p>0,05) in any of the studied regions.
At regional level  significant differences (p<0,05) were observed for the three chains. The average values  for short and medium chain in the X^th  Region, whith values of 7,55 and 51,85 % p/p respectively, were significantly higher (p<0,05) than those found in the VIII ^th and IX^th  Region. However an inverse situation was observed in the case of long chain (C44-C54) with average values of 40,13 % p/p in the X^th Region, that was significantly lower (p<0,05) than average values in the IX^th (48,78 %p/p) and VIII ^th Region (49,01 %p/p).
Season and geographic areas (regions) are factors that generated significant differences in the composition of the triacylglycerides in bovine milk fat.