响应面法优化胡萝卜膳食纤维酸奶工艺

Optimization of fermentation process for yogurt with added carrot dietary fiber by response surface analysis

将胡萝卜水溶性膳食纤维以不同比例加入酸奶中,在单因素试验的基础上,采用响应面分析法,优化膳食纤维添加量、接种量、发酵时间及发酵温度的工艺参数。结果表明,胡萝卜水溶性膳食纤维能促进乳酸菌的生长,添加胡萝卜水溶性膳食纤维前后乳酸菌活菌数分别为2.6×10~7和4.3×10~8mL^(-1),一定范围内降低酸奶的pH值,增加酸奶的持水力和黏度,并改善酸奶的组织状态。胡萝卜膳食纤维酸奶的最佳工艺参数为胡萝卜水溶性膳食纤维添加量2.17%,乳酸菌接种量3.46%,发酵温度42.3℃,发酵时间6h。该条件下制得的酸奶,香味浓郁,质地均匀,口感爽滑细腻。

Nowadays, there is growing interest to improve texture, flavour and health benefits of manufactured foods, particularly dairy based products, using natural fruit and vegetable fiber. By adding different amounts of carrot soluble dietary fiber to milk before yogurt fermenta- tion. On the basis of single factor experiments, we studied the effects of the amount of water-soluble dietary fiber carrot, inoculum size, fer- mentation time and temperature of the fermentationby Box-Behnken experimental design and response surface methodology. It was found that the added carrot dietary fiber was able to stimulate the growth of lactic acid bacteria, decrease the pH value in a certain range, enhance the water holding capacity and viscosity, and changed the texture. The number of viable bacteria was 2.6×107 and 4.3×10s mL-1, respectively, before and after the addition of carrot water soluble dietary fiber. By analyzing the experimental data using Design-Expert V 8.0.6, the opti- mum fermentation parameters Were determined as follows： 2.17% carrot soluble dietary fiber, an inoculum size of 3.46%, a fermentation tem- perature of 42.3 ℃ and time 6 h. Under these conditions, the system has the rich flavor. The texture of the yogurt is exquisite and uniform, and taste of yogurt is smooth and delicate.