龙眼发酵乳饮料加工工艺优化研究

Study on Optimization of Processing Technology of Longan Fermented Milk Beverage

【目的】探究龙眼发酵乳饮料的优化配方和发酵条件,为深化龙眼发酵乳饮料生产及推动龙眼深加工产业健康发展提供参考依据。【方法】筛选适宜龙眼发酵乳饮料加工的乳酸菌种,通过单因素试验和正交试验,探讨不同果汁含量、乳粉含量、蔗糖含量对龙眼发酵乳饮料感官的影响,测定和研究不同温度、接种量、菌种比例对龙眼发酵乳饮料生成乳酸量和感官的影响,试制龙眼发酵乳饮料。【结果】选用保加利亚乳杆菌和嗜热链球菌的混合菌发酵制备龙眼发酵乳饮料,影响感官评分因素的排序为:果汁添加量>乳粉添加量>蔗糖添加量,最优配方为乳粉添加量为10%、果汁添加量为20%、蔗糖添加量为3%。以乳酸含量和感官评分综合加权分为评价指标,最优发酵工艺为发酵温度42℃、接种量为2%、嗜热链球菌∶保加利亚乳杆菌为1∶2,发酵时间4 h。【结论】以龙眼汁、乳粉和蔗糖为原料制得龙眼发酵乳饮料酸甜度适中,口感细腻,具有龙眼清香、发酵酸香和乳香,色泽均匀乳白含浅黄色,感官评价良好。

【Objective】To explore the optimum formula and fermentation conditions of Longan fermented milk beverage,and to provide reference for the further production of Longan fermented milk beverage and the healthy development of Longan processing industry.【Method】The lactic acid bacteria suitable for the processing of longan fermented milk beverage were screened.Single factor test and orthogonal test were used to study the effects of fruit juice,milk powder and sucrose content on sensory of Longan fermented milk beverage,the effects of temperature,inoculum amount and proportion of bacteria on lactic acid production and sensory of Longan fermented milk beverage were studied,for trial production of longan fermented milk drink.【Result】Longan fermented milk beverage was prepared by mixed fermentation of Lactobacillus DELBRUECKII subsp.Bulgaricus and Streptococcus thermophilus.The factors affecting the sensory score were as follows:the addition of fruit juice>the addition of milk powder>the addition of sucrose.The optimal formula was 10%milk powder,20%fruit juice and 3%sucrose.The optimal fermentation conditions were 42℃,2%inoculum,1∶2 Streptococcus thermophilus and 4 hours fermentation time,respectively,with lactic acid content and sensory score as evaluation indexes.【Conclusion】Longan fermented milk beverage was made from Longan juice,milk powder and sucrose.The beverage had moderate acidity and sweetness,fine taste,clear Longan aroma,fermented sour aroma and frankincense,uniform colorof light yellow color and good sensory evaluation.