凝固型紫薯酸奶工艺研究

目的]优化得出凝固型紫薯酸奶的最佳工艺参数，方法]以紫薯，纯牛乳为主要原料，采用保加利亚乳杆菌和嗜热链球菌混合菌种进行发酵，制备凝固型紫薯酸奶。在单因素的基础上，通过响应面法优化紫薯添加量、蔗糖添加量、接种量和发酵温度4个因素的最佳工艺参数。结果]以感官评价为指标，紫薯经蒸制，干燥后粉碎并过100目筛以粉状添加时，产品品质较好。紫薯酸奶的最优发酵工艺为：在紫薯添加量为2．2％，蔗糖添加量为6．7％，接种量为10％，发酵温度为41℃时，发酵8h时所得产品色泽均匀，组织细腻，味道酸甜可口，风味纯正，具有浓郁的紫薯香味和酸乳风味。结论]研究可为市场开发凝固型紫薯酸乳产品提供理论依据，增加功能性酸奶种类，丰富酸奶市场。

Process of Solidified Purple Sweet Potato Yogurt

Objective] To obtain the optimal technique parameters of solidified purple sweet potato yogurt. Method ] With purple sweet po- tato, pure milk as the main raw material, the Bulgarian bacillus and Streptococcus thermopiles strains were used for preparation of solidified purple sweet potato yogurt. On the basis of single factor, response surface analysis method was used to optimize four factors, including purple potato addition, sucrose addition, inoculation and fermentation temperature. Result] The experimental results show that, the purple sweet potato by steaming, drying and crushing with 100 mesh sieve powder added into the product, the product quality is the best. Optimal purple sweet potato yogurt fermentation process is： purple sweet potato is 2.2%, sucrose dosage is 6.7%, inoculation is 10%, fermentation temperature is 41 ℃, the resulting product attractive color uniform fermentation 8 h, tissue texture delicate soft uniform, sweet and sour taste, pure flavor, with rich yogurt flavor and unique purple sweet potato flavor. Conclusion] The study can provide theoretical basis for developing solidified purple sweet potato yogurt, increasing functional yoghurt species, enriching yoghurt market.