响应面法优化草莓鲜榨汁紫外杀菌工艺

以草莓鲜榨汁为原材料,进行紫外线杀菌,研究草莓鲜榨汁厚度、紫外线照射距离和紫外线照射时间对菌落总数、霉菌和酵母菌总数杀菌率的影响。利用响应面分析法确定紫外线杀菌的最佳工艺参数为果汁厚度0.7 mm、照射距离8.0 cm、照射时间62 min,得到实际杀菌率为99.24%。在最佳工艺条件下对草莓鲜榨汁进行紫外杀菌,并与巴氏杀菌比较对草莓鲜榨汁品质指标的影响。结果表明:紫外线杀菌可以提高草莓鲜榨汁中花色苷和总酚的含量;有利于减缓草莓鲜榨汁中可滴定酸含量的降低,但对可溶性固形物无显著影响;另外紫外线杀菌降低了草莓鲜榨汁中VC的含量,但是与巴氏杀菌相比较,VC损失率减少了28.7%。这说明紫外线杀菌可以在达到商业无菌的前提下,维持草莓鲜榨汁中的营养成分。

Optimization of UV Sterilization Process of Strawberry Fresh Juice by Response Surface Methodology

In this study, fresh strawberry juice was sterilized by UV radiation. The effects of fruit juice thickness, irradiation distance and time on sterilization efficiency were investigated. The optimal process parameters were obtained by response surface methodology as follows: juice thickness 0.7 mm, irradiation distance 8.0 cm and irradiation time 62 min. Under these conditions, the sterilization efficiency was 99.24%. In comparison with pasteurization, the contents of total phenolics and total anthocyanins were increased by UV irradiation while maintaining titratable acidity. However, UV irradiation had no significant influence on soluble solid content. Additionally, VC content was decreased by UV irradiation, while compared with pasteurization, the loss rate of VC was reduced by 28.7%. These results indicate that UV irradiation can meet the requirements for commercial sterilization of strawberry juice while maintaining its quality.