抗寒桑树品种霜前后品质评价及功能品种筛选OA

[Objective]To clarify the differences in the contents of nutrients,bioactive substances and functional activities in mulberry leaves among different cold-resistant mulberry varieties before and after frost,and to screen excellent mulberry varieties suitable for edible and medicinal development in cold-resistant regions of northern China.[Methods]Five northern cold-resistant mulberry varieties were used as materials,and mulberry leaf samples were collected before and after frost,respectively.1-deoxynojirimycin(DNJ)was determined by high performance liquid chromatography-tandem mass spectrometry,polyphenols by Folin-Ciocalteu colorimetry,and total flavonoids by sodium nitrite-aluminum nitrate colorimetry.The antioxidant capacity was evaluated by ABTS,FRAP and DPPH assays,and α-glucosidase inhibitory activity was detected simultaneously.The results were subjected to comparison between varieties before and after frost,regression analysis,comprehensive evaluation and cluster analysis.[Results]There were extremely significant differences(P＜0.01)among the varieties in 1-deoxynojirimycin(DNJ),flavonoids,antioxidant capacities(ABTS,FRAP,DPPH),and α-glucosidase inhibition rate before and after frost.Before frost,Longsang1 had the highest contents of DNJ,quercetin and rutin;Liaoyu8 performed prominently in chlorogenic acid,isoquercitrin,FRAP and ABTS;while Liaolu 11 was optimal in total flavonoids,DPPH and α-glucosidase inhibition rate.After frost,Longsang1 maintained the highest DNJ content;Liaoyu 8 had the highest contents of chlorogenic acid and FRAP;Liaolu11 showed the highest contents of total flavonoids,ABTS and DPPH;both Liaolu11 and Liaoyu8 performed excellently in quercetin,isoquercitrin and α-glucosidase inhibition rate.Regression analysis indicated that among the 9 indicators measured before and after frost,DPPH was the core driving factor affecting total flavonoids.The comprehensive evaluation results showed that Liaolu 11 had the best performance and Liaoyu16 had the worst before frost;after frost,Liaolu11 still ranked first while Longsang11 was the poorest.Cluster analysis revealed that the varieties showed geographical aggregation characteristics both before and after frost.[Conclusion]Liaolu11 and Liaoyu8 are excellent mulberry varieties for the diversified food and medicinal development in cold-resistant areas of northern China,with high development and utilization value.