Composition Analysis And Activity Evaluation Of Noni Tea With Different Fermentation Degrees

Noni(Morinda Citrifolia Linn),also known as Moraida,is a genus of the genus Morinda of the Rubiaceae family.It is a tropical shrub with edible and medicinal value.Noni leaves are rich in vitamins,minerals,flavonoids,terpenoids and other active ingredients,with antioxidant,anti-inflammatory,anti-gout and analgesic effects.In this study.Noni leaves were used as the research object.comparative analysis of the effect of fermentation on the quality of Noni leaf tea,aims to provide theoretical basis and scientific basis for the deep processing and product development of Noni.The main findings are as follows:1.The main nutrients of Noni leaf tea with different fermentation degrees were tested by national standard method.The results showed that the content of carbohydrates and protein was higher in the three noni leaf teas,and the free amino acids were up to 17 kinds,mineral content up to 39 species,8 soluble sugars were detected.With the increase of fermentation degree,the protein content,free amino acid content,carbohydrate content and soluble moncsaccharide content all showed a trend of decreasing first and then increasing.2.The composition of total phenol,total flavonoids and polyphenols of Noni leaf tea with different fermentation degrees were determined by spectrophotometer and HPLC.The results showed that the content of polyphenols in Noni tea increased with the degree of fermentation.The trend of lowering and then increasing,while the total flavonoid content showed an increase and then decreased.A total of 11 free polyphenols were detected,of which rutin and quercetin were the highest,the content of different phenolic substances has different dynamic changes with the progress of fermentation.Based on the ORAC,ABTS,DPPH and reducing power in vitro antioxidant system and the three enzyme activity inhibition experiments of xanthine oxidase,a-glucosidase and angiotensin converting enzyme,the activities of different fermentation degrees of Noni tea were evaluated.The results showed that all three noni teas have strong anti-oxidation,uric acid-lowering,hypoglycemic and blood pressure lowering activities.Among them,Noni oolong tea has the best total antioxidant capacity;while Noni black tea has the strongest ABTS,DPPH free radical and reducing ability,and has the best inhibitory effect on xanthine oxidase and a-glucosidase;Noni Green Tea has the strongest inhibitory effect on angiotensin-converting enzyme.3.The HS-SPME-GC/MS method was used to analrae the aroma components of Noni leaf tea with different fermentation degrees.The results showed that 68 kinds of aroma components were separated from the three noni teas,and the alcohol content was obtained.Mainly,the green tea is as high as 24.67%,and the content of olefins,ketones and hydrocarbons increases with the degree of fermentation;the content of alcohols,esters,phenols and nitrogen-containing substances tends to decrease as the degree of fermentation deepens.4.Using LC-MS/MS-based metabolomics detection technology,combined with principal component analysis,cluster analysis,orthogonal partial least squares discriminant analysis and differential metabolite screening,and study on the dynamic changes of metabolites in Noni leaf tea.The results showed that the samples in the three groups of Noni tea were highly correlated,and there was a certain gap between the metabolites in the group.The obtained differential metabolic data was reliable.Among the groups that were screened for differential expression of significant metabolites,the differentially expressed metabolites of green tea and oolong tea,green tea and black tea,oolong tea and black tea were 226,349 and 206,respectively,and Green tea and black tea differentially expressed the most significant number of metabolites,with the largest difference between groups.