Abstract: Yogurt was prepared from raw milk and oolong tea powder with added L-theanine and muscovado sugar using a starter culture of lactic acid bacteria. The effects of the concentration of oolong tea powder, muscovado sugar and L-theanine and inoculum size on the pH value, acidity, viscosity, water-holding capacity and sensory score of yoghurt were investigated by using a combination of one-factor-at-a-time (OFAT) method and orthogonal array design (OAD). The results showed that under the conditions of 0.3% oolong tea powder concentration, 8% muscovado sugar concentration, 0.09% L-theanine concentration and 0.010% inoculum size, the sensory score, pH value, acidity, water-holding capacity, and total viable count of the prepared yogurt were 96 points, 4.54, 72 °T, 67.34%, and 5.78 × 109 CFU/g, respectively. The product had a rich flavor, bright color, exquisite texture, prominent muscovado sugar-like flavor, strong aroma, and smooth taste without suspended particles.

Key words: oolong tea powder; L-theanine, muscovado sugar; lactic acid bacteria; orthogonal array design

摘要： 以生牛乳和乌龙茶粉为主要原料，添加L-茶氨酸、黑糖和乳酸菌等配料共同发酵，研发黑糖乌龙茶酸乳。通过单因素试验和正交试验分别考察乌龙茶粉添加量、黑糖添加量、L-茶氨酸添加量和发酵剂接种量对黑糖乌龙茶酸乳pH值、酸度、黏度、持水力和感官评分的影响。结果表明：在乌龙茶粉添加量0.3%、黑糖添加量8%、L-茶氨酸添加量0.09%、发酵剂接种量0.010%条件下，黑糖乌龙茶酸乳感官评分为96 分、pH 4.54、酸度72 °T、持水力67.34%、乳酸菌活菌数5.78×109 CFU/g，产品乌龙茶风味浓郁、色泽明亮、质地细腻、黑糖风味突出、口感香浓顺滑、无颗粒悬浮。

关键词: 乌龙茶粉；L-茶氨酸；黑糖；乳酸菌；正交试验