Abstract:The current research studied the influence of milk fat mass fraction on sensory profiles of whole milk coffee with different roasting degrees. The just noticeable difference (JND) threshold of consumers in fat content of whole fat milk coffee was also investigated. Hereby, for light-, medium- and dark-roasted coffee, the flavor of the milk coffee with varied milk fat contents was evaluated by a quantitative descriptive analysis. Meanwhile, the JND threshold of fat mass fraction in whole milk coffee was determined by a three-alternative forced-choice detection. The results showed that the decrease of milk fat content could enhance the intensities of sourness, bitterness, astringency, smoky flavor, burnt flavor, roasted flavor, raw bean flavor and sour fragrance, and inhibit sweetness, body, caramel flavor and milky flavor. A consistent trend of influence was observed in all three coffees with different degrees of roast. However, the increased degree of roast caused more significant effect of milk fat on the flavor of coffee. Further analysis of the threshold tests showed that JND thresholds of the mass fraction of fat in light-, medium- and dark-roasted coffee were 2.59%, 2.45% and 2.36% (mass fraction), respectively. Female consumers were more sensitive to changes in fat, and their JND thresholds of fat mass fraction in deep-roasted coffee were significantly lower than those of men. The results could provide a theoretical basis for the development of low-fat milk coffee.
