Sensory Discrimination of Fat and Solids-Not-Fat in Milk

Abstract

A dual-standard paired-comparison method was used by a highly trained panel to detect differences in fat and in solids-not-fat (SNF). Homogenized milk of desired composition was prepared by special techniques, using heat-treatments below the legal minimum for pasteurization to avoid cooked flavors, and a vacuum treatment to remove volatiles. In milks containing 0, 2.0, 4.0, and 6.0% fat at base SNF levels (prepared from nonfat milk solids) of 8.5 and 10.0%, the level of fat and SNF did not influence significantly the detection of added SNF (approximately 0.5% added SNF detected 67% of the time). In specially prepared fluid milk, however, it was slightly easier to detect SNF in skimmilk than in milk containing 2.0 or 3.5% fat. In skimmilks, the level of SNF (8.5 vs. 10.0%) influenced detection of fat, but in whole milk the difference was not significant. Interpolation of the data suggested minimum differences for 67% correct response of 0.3% fat in skimmilk (8.5% SNF), 0.8% in fortified skimmilk (10.0% SNF), and 1.5% in whole milk (8.5 and 10.0% SNF). The data emphasize that in sensory discrimination of concentration differences, SNF are more important than fat. Temperature and order of serving did not influence detection of differences.