Comprehensive evaluation of medicinal and nutritional quality of 16 mulberry resource leaves in Guangxi

【Objective】 To clarify medicinal and nutritional components of different mulberry varieties and to evaluate medicinal and nutritional qualities of 16 mulberry resource leaves，so as to provide theoretical reference for the diversified development of mulberry.【Method】 Taking 16 mulberry resource leaves preserved in the mulberry resource garden of the sericulture technology extension station of Guangxi Zhuang Autonomous Region as experimental materials ，9 indexes，content of polyphenol，deoxynojirimycin（DNJ），polysaccharide，protein，fat and Vitamin C（VC）in mulberry leaves were measured.Principal component analysis，correlation analysis and membership function method were used for comprehensive evaluation.【Result】There were significant differences in 9 components of 16 mulberry resource leaves.Among them，the difference of DNJ content among varieties was the largest，the coefficient of variation was 41%，and the average value was 1803.17 μg/g.Guiyou 94-936 has the highest DNJ content，3239.25 μg/g，and the content of DNJ in Guiyou 94-168 was the lowest，747.73 μg/g.The difference of water content among varieties was the smallest，with a coefficient of variation of only 6% and an average of 83.93%.The water content in Guiyou 94-936 was the highest，91.46%，and that of A17 was the lowest，71.02%.Correlation analysis showed that polyphenol content was significantly correlated with tannin content（P<0.05）.Correlation analysis and principal component analysis showed that the main indexes affecting the comprehensive quality of mulberry leaves were phenols，alkaloids，polysaccharides and proteins.The comprehensive score of 16 mulberry resource leaves was obtained by calculating the value and weight of the membership function.The top 3 in the comprehensive evaluation of the medicinal quality of the 16 mulberry resource leaves were Guiyou 94-936，Test 11 and Guiyou 8012，while the top 3 in the comprehensive evaluation of the nutritional quality were Guiyou 94-936，Guiyou 92L-26 and Hu 107.【Conclusion】 According to the comprehensive evaluation of nutritional quality and health care quality of mulberry leaves，Guiyou 94-936 can be used as a candidate for medicinal and food homologous varieties.Polyphenols，DNJ，and polysaccharides can be used as evaluation indicators for the medicinal quality of mulberry，while the content of protein，fat and VC can be used as evaluation indicators for the nutritional quality of mulberry.