Nutrition Analysis Of Different Millets And Effects Of Processing And Storage On Their Phenolic Contents

At present,the nutritional datas of different millet cultivars are not complete and the change of phenolic content in millet during low temperature storage is not clear.In addition,it lacks theoretical support for the processing of millet and the mechanism of phenolic content change.Therefore,we detected the nutrients composition of 11 vatieties of millet and the effect of dehulling,steaming and cooking on the phenolic content and antioxidant activity of 6 varietie of millets.What is more,we studied the effect of cooking and baking conditions on the phenolic content of Fenghonggu.At last,we studied the effect of storage temperature,storage time and the enzymatic activity on the phenolic content of millet.Firstly,in order to supplement the nutrition data of different varieties of millet,the nutritional composition of 11 varieties of millet were detected.The results showed that the moisture content ranged from 8.66% to 11.47%,ash content ranged from 2.05% to 3.25%,the fat content ranged from 1.81% to 3.35% and unsaturated fatty acids of Jingfen02 was up to 89.25%.Linoleic acid was the most abundant fatty acid in 11 varieties of millet and it's content in Jingfen02 was up to 70.28%.Crude protein content ranged from 8.42% to 10.70%.Glutamic acid and leucine were the most abundant amino acids which were up to 2350.96 and 1462.00 mg/100 g,respectively.In addition,the total dietary fiber content ranged from 10.33% to 21.35%.Dietary fiber mainly exsisted in soluble form and the content accounted for 74% to 98% that of the total dietary fiber content.What is more,the 11 varieties of millet were also rich in minerals including Fe(29.36~75.00 mg/kg)and Zn(19.53~39.66 mg/kg).Secondly,6 varieties of millet were selected on account of the higher total nutrient content.After dehulling process,the effect of the treatments on the phenoic content,phenoilc acids content and the antioxidant activity of millet were studied.It turned out that the total phenolic content(TPC)and antioxidant activity of different process were Whole > Dehulled.72% of the phenolic compounds in millet existed in the bran.Besides,the effect of cooking,steaming and baking on the phenoic content,phenoilc acids content and the antioxidant activity of millet were studied.It turned out that the total phenolic content(TPC)and antioxidant activity of different process were Dehulled > Cooked > Steamed.The results showed when the conditions of cooking millet were cooking temperature 100°C,sample and water ratio 1:20 and cooking time 40 min,the phenolic content of dehulled millet was highest.When the conditions of baking millet were baking temperature 237°C and baking time 8 min,the phenolic content of dehulled millet was highest.Finally,after 16 months storage at-20°C,the TPC of whole Jigu31 and whole Jingu21 stored decreased by 68% and 35%,respectively.The TPC of dehulled Jigu31 and dehulled Jingu21 decreased by 41% and 51%,respectively.Also,with the extension of storage time,the phenolic acids of whole and dehulled Jigu31 stored at 4°C and-20°C all decreased.Additionally,the TPC of whole and dehulled Jigu31 stored at 4°C were 1.95 and 1.31 times than those at-20°C,respectively.Compared with-20°C storage,the activity of polyphenol oxidase,Peroxidase and feruloyl esterase stored at 4°C was lower,and the free phenolic content had no significant difference,bound phenolic content and total phenolic content were higher.