Study On Color Characteristics,Active Substance Composition And Vitro Antioxidant Capacity Of Fermented Stems And Leaves Of Chenopodium Album L

stems and leaves of Chenopodium album L.(CSL)have high nutritional and medicinal value and can be used as feed and feed additive.fermented stems and leaves of Chenopodium album L.(FCSL)is a kind of fermented plant raw material rich in many active ingredients.Using probiotic solid state fermentation to treat the stems and leaves of Chenopodium album L can change the apparent color,enrich its active substances,improve its activity,and provide technical support for its high value-added development and utilization.In this study,the effects of solid fermentation on the apparent color characteristics of stems and leaves of Chenopodium album L and their quality assessment,extraction and composition analysis of main active ingredients,and antioxidant activity of water extracts were studied.The results were as follows:Exp.1 Changes in apparent color characteristics and quality assessment of fermented Chenopodium album L stems and leaves.In this experiment,the p H value,the main active components and the color characteristics of the fermentation Chenopodium album L were analyzed over time,and the correlation between the active components and the color characteristics was established.The results showed that:(1)p H value of stems and leaves of Chenopodium album L decreased gradually with the extension of fermentation time;The contents of polyphenols,polysaccharides and reducing sugars reached the highest at 24 h,and the contents of flavonoids reached the highest at 60 h.(2)The color characteristics of the stems and leaves of the fermented Chenopodium album L were significantly correlated with the contents of polysaccharides,reducing sugars,polyphenols and flavonoids.(3)With RGB and HSV color characteristics as independent variables,the quality assessment model of stems and leaves of fermenting Chenopodium album L was constructed based on random forest algorithm.The accuracy,recall rate,F1 score and accuracy of the model were 0.859,0.914,0.886 and 0.900,respectively.The accuracy of random forest model(80%)was higher than that of manual evaluation(60%).The establishment of this model provides technical support for the standardization evaluation of stem and leaf products of fermented Chenopodium album L.Exp.2 Water extraction technology and composition analysis of the main active components from the stems and leaves of the fermented Chenopodium album L.The aim of this experiment was to study the effects of fermentation on the content and composition of soluble substances in the stems and leaves of Chenopodium album L.The results were as follows:(1)The optimum hot water extraction process of the stems and leaves of the fermented Chenopodium album L was as follows: extraction temperature was80℃,ratio of material to water was 1:20,water extraction time was 90 min,and the water extraction rate was 24.90% under these conditions.(2)Fermentation significantly increased the contents of soluble polysaccharides,polyphenols and flavonoids in stems and leaves of Chenopodium album L,and changed the composition of monosaccharides,phenolic acids and flavonoids.(3)A total of 163 phenolic acids were detected in stem and leaf water extracts of Chenopodium album L before and after fermentation,of which 45 were significantly up-regulated and 55 were significantly down-regulated.The contents of ferulic acid methyl ester,ferulic acid ethyl ester,dihydroferulic acid,p-coumaric acid,vanillic acid,gentian acid and syringic acid in FCSL aqueous extract were significantly up-regulated.(4)A total of 179 flavonoids acids were detected in stem and leaf water extracts of Chenopodium album L before and after fermentation,of which 27 were significantly up-regulated and 67 were significantly down-regulated.glycosidic flavonoids such as quercetin,kaempferol and isorhamnetin were significantly up-regulated and glycosidic flavonoids such as quercetin glycosides,kaempferol glycosides and lignan glycosides were significantly down-regulated in the aqueous extracts of FCSL.Exp.3 In vitro antioxidant activity of aqueous extracts from the stem and leaves of the fermented Chenopodium album L.In this study,the antioxidant activity of CSL and FCSL aqueous extracts was evaluated by measuring DPPH free radical clearance,hydroxyl free radical clearance and reducing power.The results showed that the water extracts from the stems and leaves of Chenopodium album L showed a certain antioxidant capacity before and after fermentation,and it was dose-dependent.In the range of 0.5-1.5mg/m L,FCSL had stronger DPPH free radical scavenging ability than CSL.In the range of 0.5-2.0mg/m L,FCSL has stronger hydroxyl radical scavenging ability and reducing power than CSL.In summary,the color characteristics of the stems and leaves of the fermentation Chenopodium album L are significantly correlated with the content of active ingredients,and the quality of the stems and leaves of the fermentation Chenopodium album L can be automatically assessed by machine vision technology.In addition,fermentation can improve the content,composition and antioxidant capacity of stems and leaves of Chenopodium album L.This study provided a theoretical basis for developing the stems and leaves of fermented Chenopodium album L as a natural antioxidant feed additive.