Evaluation On The Biological Activity Of Polyphenols From Lotus Seedpod And Its Application In Mooncakes

With the steady growth of lotus planting area,the development of lotus industrialization has become more and more mature.As a by-product of the lotus industry,lotus seedpod is mostly discarded as waste because it is inedible.Studies have shown that lotus seedpod is rich in polyphenols,including proanthocyanidins,quercetin,hyperoside and kaempferol.In this research,lotus seedpod polyphenols were extracted and purified.The anti-oxidation,anti-glycation and anti-inflammatory activities of LSPs were evaluated,and its application in mooncakes was explored,which would broaden the application fields of LSPs in foods.The main results are summarized as follows:(1)Single factor and response surface experiments showed that the optimal extraction conditions for polyphenols from lotus seedpod were:extraction time of 43 min,ethanol volume fraction of 40%,material-to-liquid ratio of 1:40.The yield of polyphenols can reach 8.54%.The UV-Vis,FT-IR and UPLC-ESI-Q-TOF results of lotus seedpod polyphenols(LSPs)purified by AB-8 macroporous resin and ethyl acetate extraction showed that LSPs contained the typical characteristics of polyphenols,and were composed of 8 types of polyphenols.The component units were catechins,epicatechins,gallocatechins,epigallocatechins and procyanidins.(2)LSPs performed well in scavenging DPPH and ABTS free radicals,and there was a good dose-effect relationship between the scavenging ability and the concentration of LSPs.LSPs also can scavenge the OH and O₂^-radicals,but there was no concentration-dependent relationship.The results of the cell oxidative damage model showed that LSPs exhibited no obvious cytotoxicity at low concentrations,and can increase the survival rate of hydrogen peroxide-damaged cells.When LSPs were included,the levels of ROS,MDA and LDH in H₂O₂induced RAW264.7 macrophages were reduced.The levels of GSH,T-AOC,GSH-PX,SOD and CAT were increased and the degree of cell peroxidation was reduced.(3)A food modle system including bovine serum albumin(BSA)and glucose was constructed.Under the simulating baking conditions of mooncakes,the effect of LSPs on the formation of fluorescent AGEs(f AGEs)was investigated to evaluate their anti-glycation effects.The level of f AGEs generated at 130°C gradually increased with time,while it first increased and then decreased at 170°C.The level of f AGEs produced at 170°C was much higher than that at 130°C.However,when LSPs were added,the level of f AGEs produced at 130°C and 170°C gradually decreased to a constant amount as the concentration of LSPs increased.(4)AGEs can induce inflammation in the body,resulting in adverse health effects.Therefore,the anti-inflammatory activity of LSPs was evaluated by the cellular inflammation model.LSPs promoted cell growth,increased the survival rate of inflammatory RAW264.7macrophages,and reduced the ROS,NO,TNF-?,IL-1?,IL-6 and IFN-?levels.The expressions of pp65,c-Jun,p38,p ERK,JNK and p I?B-?in inflammatory RAW264.7 macrophages treated with LSPs were all reduced in a concentration-dependent manner.LSPs inhibited MAPK/AP-1,MAPK/NF-?B and I?B-?/NF-?B pathways and captured free radicals,thus inhibiting cell inflammation and reducing the levels of intracellular inflammatory mediators.(5)LSPs were applied to the mooncake production,the effects of LSPs on the level of f AGEs and the quality of mooncake skin were investigated.When the concentration of LSPs was higher than 0.2 mg/g,the inhibition rate of f AGEs in mooncake skin can reach 45%.The addition of LSPs within the measuring range(0.1?0.5 mg/g)did not cause obvious damage to the texture and taste of mooncake skin.When the concentration of LSPs was in 0.1?0.4 mg/g,the total color difference of mooncakes skin was moderate and acceptable.Sixty-eight types of volatile organic compounds in mooncake skins were identified by GC-IMS,including 1 olefin,16 aldehydes,10 alcohols,1 acid,8 esters,1 ether,5 ketones,and 2furans.When the concentration of LSPs was in 0.1?0.4 mg/g,the scores of volatile aroma substances in the mooncakes skin were all above 85 points,which was regarded as acceptable.At this time,the original taste and flavor of the mooncakes skin can be maintained,and the content of f AGEs can be effectively reduced.Lotus seedpod,as a resource rich in polyphenols,has been comprehensively evaluated for its beneficial effects.It is promising for LSPs to be appled as a functional food ingredient,and the effective use of lotus seedpod resource will be exploited.