不同贮藏温度和时间下采后甘薯糖化效果的比较

Comparison of Saccharification Effect of Post -harvest Sweet Potatoes under Storages at Different Temperatures and for Different Time Periods

摘要:

针对我国甘薯因采后糖化条件不明确导致加工产品品质不稳定的问题，该研究以“烟薯25号”为实验材料，通过比较不同贮藏温度和时间下采后鲜薯及其烤甘薯淀粉、糖组分、感官、质构特性等的差异，并采用相关性分析法进行综合评价，筛选出甘薯最佳的糖化温度和时间。结果表明，与刚采收鲜薯相比，不同贮藏条件下鲜薯淀粉含量均有所下降，糖组分含量有所提高，其中，12 ℃贮藏21 d时鲜薯还原糖含量显著增加，增幅达37.39%，且果糖含量最高。12 ℃下贮藏12 d的甘薯烤制后，葡萄糖、果糖、蔗糖、麦芽糖含量较采后直接烤制（对照组）分别提升11.90%、17.76%、64.72%和3.67%，甜度系数（0.75）和Brix值（31.80 °Bx）也显著提升（P<0.05），高于对照组（0.72，25.20 °Bx）和其它实验组（0.65~0.76，18.80~29.50 °Bx）。感官评价及质构特性结果表明，该处理条件下烤甘薯风味与对照组无显著差别，但具有最高的甜味响应值（7.50）、较高的鲜味响应值（6.70）和较低的硬度（840.80 g）。综上所述，12 ℃贮藏12 d是适宜甘薯糖化的最佳条件，该结果可为鲜薯加工制品品质提升提供理论依据和技术指导。

Abstract:

In order to solve the problems of unstable quality of processed sweet potato products due to unclear postharvest saccharification conditions in China, in this study, "Yanshu No. 25" was used as the experimental material, the differences in starch content, sugar components, sensory and texture characteristics of fresh and roasted sweet potatoes under different storage temperature and time. The optimal saccharification temperature and time for post-harvest fresh sweet potatoes and roasted sweet potato were compared, and a comprehensive evaluation was conducted by correlation analysis to screen out the optimal saccharification temperature and time of sweet potatos. The results showed that compared with freshly harvested sweet potatoes, the starch contents of the fresh sweet potatoes stored under different storage conditions decreased whilst their sugar contents increased, among them, the reducing sugar content increased significantly (by 37.39%) with the fructose content being the highest after storage at 12 ℃ for 21 d. The contents of glucose, fructose, sucrose and maltose of the roasted sweet potatoes after being stored at 12 ℃ for 12 d increased by 11.90%, 17.76%, 64.72% and 3.67%, respectively, compared with the sweet potatoes roasted straightly after harvest (the control group). The sweetness coefficient (0.75) and Brix value (31.80 °Bx) of the roasted sweet potatoes after being stored at 12 ℃ for 12 d were also significantly higher than those of the control (0.72, 25.20 °Bx) and other experimental groups (0.65~0.76, 18.80~29.50 °Bx). The results of sensory evaluation and texture characteristics showed that the roasted sweet potatoes under such treatment conditions exhibited a flavor essentially the same as that of the control, and had the highest sweetness response value (7.50), relatively high umami response value (6.70) and lower hardness (840.80 g). In conclusion, a storage at 12 ℃ for 12 d was identified as the optimal conditions for saccharification of post-harvest sweet potatoes. The results could provide a theoretical basis and technical guidance for improving the quality of processed products from fresh sweet potatoes.