高温短时热空气处理促进甘薯愈伤的工艺优化.

Hot air treatment is currently the main pretreatment method to promote postharvest callus healing of sweet potatoes. To improve the existing problem, such as high energy consumption, low efficiency, instability, in sweet potato callus formation technology. The purpose of this study was to find the optimal conditions of High Temperature Short Time (HTST) hot air treatment which could promote postharvest sweet potato callus formation. The lignin content, soluble solid content, weight loss rate, and decay rate of sweet potato were selected as the key indices in this study. The indices of sweet potatoes were measured after 15 d of (25±5) ℃ storage. Single-factor and response surface methods were used to optimize the callus formation conditions of sweet potato within hot air treatment. In the single-factor experiment, the temperature and time of treatment were used as variables. The HTST hot air treatment temperature range was set as 40, 45, 50, 55, 60 and 65 ℃, and the treatment time range was set as 30, 60, 90, 120, 150, and 180 min. By Design-Expert 8.0 software, a central combination of two factors and three levels was used to design the central composite design for sweet potato hot air treatment. The quadratic multivariate regression equations of lignin, soluble solids, weight loss rate, and decay rate were obtained. The results of variance analysis of lignin content, soluble solid content, weight loss rate, and decay rate of sweet potato after hot air treatment showed that the four equations of hot air treatment had high significance, good fitting degree, and small test error. Hence, this model could be used to predict the data of sweet potato after callus formation. The results of the single-factor experiment showed that the soluble solids and starch content of sweet potato after callus formation could be maximized maintained when the treatment time reached 150 min. And the decay rate and weight loss rate after storage could be maximized reduced. At the same time, When the hot air treatment temperature reached 50 ℃, the soluble solid content and starch content of sweet potato after shelf-life storage was significantly higher than that of other treatment temperatures. Meanwhile, the weight loss rate and the decay rate were the lowest in all treatment groups. Within the single-factor experimental results, the two-factor and three-level center combination design of the treatment temperature and treatment time was performed for quadratic multiple regression fitting. The quadratic multinomial regression equations of lignin content, soluble solid content, decay rate, and weight loss rate were obtained. At the same time, the model was tested and the four equations were found to have high significance and a good degree of the fitting. The model was used to predict the four parameters of sweet potato callus formation and analyze the response surface. The results showed that the callus formation effect of sweet potato in shelf-life storage was more influenced by hot air treatment temperature than treatment time. On the other hand, the optimal conditions for promoting the callus formation of sweet potato were 49 ℃ and 137 min, which could effectively promote the lignin synthesis, weight loss rate, and decay rate of sweet potato callus. Compared with the control, the content of starch was higher by 76.30%, soluble solid content was higher by 32.08% and ascorbic acid content was higher by 81.19% in sweet potato after shelf storage, which was all significantly increased by hot air treatment. Moreover, the weight loss rate and decay rate of sweet potato after storage were reduced by 22.14% and 79.95%, respectively. All the five indices provided the 49 ℃ and 137 min was an optimized post-partum callus process for sweet potato production. [ABSTRACT FROM AUTHOR]