Effect Of Varieties,Growth Periods And Storage Temperatures On Texture Quality Of Sweetpotatoes

Sweetpotato is an important food crop in China.Different products of sweetpotatoes need raw materials with different processing qualities.In recent years,there have been many studies on the nutritional qualities of sweetpotatoes.However,the texture qualities,as one of the most important criteria for the quality evaluation of sweetpotatoes,are rarely reported.In this paper,12 sweetpotato varieties were used as materials to explore the differences of texture.Meanwhile,Xinxiang,Zheshu75 and Nonglin54 were used as materials to explore the effect of different growth periods and storage temperatures on the texture.The main innovative conclusions were as follows:(1)There were significant differences in texture among different sweetpotato varieties(p(27)0.05).Hardness and dry matter content of fresh sweetpotatoes showed a significant positive correlation(r=0.416,p<0.05).Adhesiveness and reducing sugar content of roasted sweetpotatoes showed a extremely significant positive correlation(r=0.470,p<0.05).12 sweetpotato varieties can be divided into 3 categories according to the texture characteristics by cluster analysis.The first category included Zheshu70,Zheshu259,ZhezishuNo.3 and Guangshu87.The second included Xinxiang,Zheshu75,Zheshu20 and Zheshu13.The third included Shangshu19,ZhezishuNo.1,Xushu22 and Nonglin54.The results of cluster analysis showed that the hardness range of roasted sweetpotatoes in fresh-eating variety was 8.05-9.93 N,and the hardness of sweetpotato varieties using for starch processing was more than 150 N.(2)In the growth period of 100-120 d,the hardnesses of the fresh tubers of Xinxiang,Zheshu75 and Nonglin54 were more than 150 N,which were suitable for starch processing.Xinxiang,Zheshu75 and Nonglin54 were suitable for roasted processing in the growth period of 100 d,120 d,140 d,respectively.In the growth period of 140 d,Xinxiang was suitable for sweetpotato chips processing,however,Zheshu75 and Nonglin54 were not suitable for sweetpotato chips processing.(3)During the storage,dry matter contents,amylase activities and hardnesses of sweetpotatoes showed a increased trend,and starch contents and reducing sugar contents showed a decreased trend.There were significant differences in dry matter contents of 3 sweetpotato varieties at different storage temperatures(p<0.05).Dry matter contents of Xinxiang,Zheshu75 and Nonglin54 were the highest,accounting for 34.31%,34.09% and 33.29% respectively,when they were stored at 14 ? for 110 d.Dry matter content of Xinxiang was the highest at the storage period of 110 d,accounting for 37.46% when they were stored at 25 ?,meanwhile dry matter contents of Zheshu75 and Nonglin54 were the highest in the storage period of 90 d,accounting for 40.45% and 35.27% respectively.The hardness of Xinxiang and Zheshu75 were the highest at the storage period of 90 d,and the hardness of Nonglin54 was the highest at the storage period of 110 d at different temperatures.The nutritional quality of sweetpotatoes decreased significantly,while the hardness increased significantly in the storage period of 60-90 d.The above results indicated that there was a close relationship between hardness and storage quality in sweetpotatoes.