食用木薯块根冻结特性及代谢产物分析

为了解木薯块根冻结特性及其代谢产物，以食用木薯品种“华南9号”为研究对象，通过电导率法测定块根头、中和尾3个部位的冻结变化规律及相关影响因素，结合非靶向代谢组学进行差异代谢物分析。结果表明:木薯块根不同部位冰点范围为?0.6至?1.1 ℃，但发生冻结的时间不一致；不同部位的可溶性固形物含量与淀粉含量最高值均出现在头部，分别为7.00%和26.84%，但各部位间的含量差异不显著（P>0.05），而含水量最高值出现在尾部，为64.07%；相关性结果分析发现，冰点与可溶性固形物、含水量呈负相关关系，与淀粉含量呈正相关关系。非靶向代谢组学分析发现，与对照相比冰温处理存在41个具有显著差异表达的代谢物，以苯丙氨酸代谢途径富集程度最高，共有9个显著差异代谢物。该途径中马尿酸-苯甲酸-水杨酸通路的马尿酸、苯甲酸表达上调，这可能与块根对低温应答响应有关。该研究结果可为今后木薯块根低温贮藏提供理论参考。

Freezing Characteristics and Metabolite Analysis of Edible Cassava Root

In order to understand the freezing characteristics and metabolites of cassava root, the edible cassava variety “South China 9” was taken as the research object, by measuring the freezing-law and related influencing factors at the head, middle and tail of cassava root, combined with non-targeted metabolomics to analyze the differential metabolite. The results showed that: The freezing temperature was from ?0.6 to ?1.1 ℃ in different parts of root, but the freezing time was different. The highest values of soluble solid content and starch content in different parts appeared in the head, which were 7.00% and 26.84% respectively, but there was no significant difference among different parts (P>0.05), while the highest value of water content appeared in the tail, which was 64.07%. Correlation analysis showed that freezing point was negatively correlated with soluble solids and water content, and positively correlated with starch content. Compared with control, 41 differential metabolites were screened under low treatment by the non-targeted metabolomics, and the enrichment degree of phenylalanine metabolic pathway was the highest, with a total of 9 significant differential metabolites. In this pathway, the expression of hippuric acid and benzoic acid was up-regulated, which might be related to the response of root tubers to low temperature. The results provide theoretical reference for low-temperature storage in the future.