THE INFLUENCE OF FAT ON THE SENSORY PROPERTIES, VISCOSITY, AND COLOR OF LOW-FAT MILK

A sensory panel was trained to assess appearance, aroma, flavor, and textural attributes of milk containing various percentages of fat. The relative viscosity and color of the milk were also measured. Milk appearance had a profound effect on the perceived mouthfeel. There was a correlation of the L-value (whiteness), a-value (greenness), and b-value (blueness) for the milk with the perceived color and mouthfeel. As fat content was increased, the milk was whiter, less green, and less blue. Similarly, sensory scores for appearance and mouthfeel attributes increased as fat content increased from 0 to 2%. Panelists were given the samples under red lighting to mask the milk color. Under these conditions, the perceived mouth coating, residual mouth coating, and thickness of 2% fat milk were decreased from those of the same samples tested under normal light. Our results suggested that a fat substitute for fat-free milk needs to change the appearance more than the tactile attributes of the milk. A successful fat substitute should alter the color of fat-free milk such that the L-, a-, and b-values are approximately 81, -3.7, and 2.9, respectively, based on L-, a-, and b-values of 74, -6.7, and 1.1 for skim milk.