Abstract: [Objective] Pineapple flavored double protein yogurt was prepared using pure milk,black soya bean powder,trehalose,and concentrated pineapple juice as raw materials,with Streptococcus thermophilus and Lactobacillus bulgaricus as fermentation agents. [Mothod] On the basis of single factor experiment,orthogonal experiment and fuzzy mathematical sensory evaluation were used as the main indicators to obtain the optimal process conditions for double protein yogurt. [Result] The mass ratio of black soya bean milk to pure milk was 3:1,trehalose was 5%,concentrated pineapple juice was 15%,fermentation time was 6 h,strain addition was 2%,and fermentation temperature was 42℃. [Conclusion] Under these process conditions,the prepared yogurt appears light green,with a significant pineapple aroma and yogurt specific fermentation flavor.The taste is moderate in acidity and sweetness,with a delicate texture and a sensory evaluation score of 92.15.

Key words: pineapple, double protein yogurt, black soya bean, trehalose, fuzzy mathematics