Inhibition Of Flavonoids On The Harmful Products From Maillard In Protein Beverages

Beverage as a unique food,is popular among consumers.However,most of beverages,especially plant protein beverages(soymilk and soybean powder),contained carbohydrates,protein,fat and other ingredients.It is easy to produce the harmful intermediate products of Maillard reaction(1,2-dicarbonyl compounds,such as methylglyoxal and glyoxal)and advanced glycation end products(AGEs)during processing and storage.This study detected the content of MGO and GO in 95 types of beverages by gas chromatography in China.For plant protein beverage(soybean milk and soybean meal),the influence factors of MGO,GO and AGEs were investigated.The flavonoids(quercetin,rutin,genistein,luteolin and catechin)were applied to soybean milk and soybean powder,which aimed to study the inhibitiory efficacy during processing and storage.Ultra high performance liquid chromatography was used to investigate the loss of flavonoids during manufacturing.Change mechanisms of flavonoids were analyzed in soybean milk and soybean powder system by liquid chromatography-mass spectrometry(HPLC-MS).1 The content of MGO and GO in eight kinds of beverages,saled in China,were detected by gas chromatography.All samples,even without sugar,sugar mainly come from raw materials,contained one or both 1,2-dicarbonyl compounds(MGO and GO).Among these beverages,the lowest average and relatively lower content of GO and MGO were found in the traditional plant beverages(because of containing natural inhibitors).In the protein beverage,the level of MGO(Max.716.7 ?g/100mL)and GO(Max.587.5p,g/100mL)were remarkably higher than all other beverages.These results indicated that the ingredient in the formula,such as,protein or fat,was linked to an increase of MGO(GO).2 In soymilk system,MGO and GO are both affected by sweeteners.A highly significant linear correlatio:n was observed between the level of GO and the content of fat,while the level of MGO did not obviously vary with increasing concentration of the fat(1.0-3.0%).Boiling time(1-5 min)had little effect on MGO and GO in soymilk.The effect of sugar on AGEs and 1,2-dicarbonyl compounds(MGO+GO)were in the same order,and the effect order of sweetener inducement are as follow:xylitol<sucrose<fructose syrup<glucose<fructose.Generally,boiling time,the amount of sugar and fat content showed a positive correlation with AGEs.In soybean powder processing system,the higher pH(6.0-8.0)and inlet temperature(130-210?)are,the more content of MGO,GO and AGEs have.While solid-liquid ratio(1:5?1:7 ? 1:9)has a negative effect on MGO/GO and a positive effect on AGEs.The formation of MGO and GO has a markedly positive correlation of with the concentration of maltodextrin(0-20.0%),which seems to have the opposite role on AGEs.During storage,the content of MGO/GO and AGEs increased with the increase of temperature and time.In the first month,MGO,GO and fluorescent AGEs increased significantly and kept a relatively flat state during the second month.3 By building the model system:flavonoid-(MGO+GO),the kinetic process of different kinds of flavonoids(quercetin,rutin,genistein,luteolin and catechin)with GO and MGO was studied under high temperature(100?).Within 60 min,as the reaction time went on,the inhibitory effect of five kinds of flavonoids on MGO(GO)was increasingly stronger.When MGO(GO)was at a certain concentration,the more content of the flavonoids is,the higher the inhibition rate have.In the soybean milk and soybean powder,the dose effect relationship of MGO,GO and AGEs with five kinds of flavonoids were investigated.The results showed that five kinds of flavonoids all have a good inhibitory effect on protein glycosylation.The higher the concentration of flavonoids(0.2-2.0 mmol/L)is,the better inhibitory efficacy the glycosylation have.The optimum dosage is 2.0 mmol/L.During storage,the inhibitory effect of flavonoids on MGO,GO and AGEs have a growing trend.The loss rate of quercetin and luteolin in soymilk and soy powder were detected via UPLC-DAD.HPLC-ESI-DAD-MS was used to analyze structural changes of quercetin and luteolin,quercetin and MGO formed 3 adducts;luteolin and MGO formed one adduct.