牛奶脂肪对不同烘焙程度咖啡感官品质的影响

Effect of Milk Fat on Sensory Quality of Coffee with Different Degrees of Roast

摘要:

作者主要研究牛奶脂肪质量分数对不同烘焙程度牛奶咖啡风味的影响及全脂牛奶咖啡中脂肪质量分数的消费者差别阈值。首先，针对浅、中、深3个烘焙程度的咖啡，采用定量描述性分析法评价不同脂肪质量分数牛奶咖啡的风味；其次，采用三点选配法测量全脂牛奶咖啡中脂肪质量分数的差别阈值。结果表明，随着脂肪质量分数降低，咖啡的酸味、苦味、涩味、烟味、煳味、焦香味、生豆味和酸味（鼻前香气）逐渐增强，而甜味、醇厚感、焦糖味和奶香味减弱，这些影响在3种不同烘焙程度咖啡中的变化趋势一致，但随着烘焙程度加深，牛奶脂肪的变化对咖啡风味的影响程度也会上升。进一步通过分析阈值测试结果发现，脂肪质量分数在浅、中、深烘焙咖啡中的差别阈值分别为2.59%、2.45%和2.36%（质量分数）。女性消费者对脂肪的变化更敏感，脂肪质量分数在深焙咖啡中的差别阈值显著低于男性。研究结果可为低脂牛奶咖啡的开发提供理论依据。

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.