Folate Stability Analysis In Wheat And Fresh Corn During Storage And Processing

Folates are important vitamins to maintain human health,but they are not stable.Light,heat,ultraviolet radiation,oxidation and different p H can cause the degradation or transformation of folates.In this study,the stability of folates during storage and processing of wheat and fresh corn products was analyzed.The main results were as follows:1.Six wheat varieties were selected to analyze the folate loss during grain storage,flour processing and foods preparation.It was found that the folates of wheat grain began to decrease(14%)when stored at room temperature for 4 months,and decreased significantly(26%)after stored for 8 months.Flour processing can lead to serious loss of folates,the folate retention in flour is only 29%.The folate levels in noodles,steamed bread and bread were 1.93-2.29 ?g/100 g,12.53-19.83 ?g/100 g and 30.01-45.92 ?g / 100 g fresh weight,respectively.The folate content of steamed bread and bread was 1.5-4.0 times higher than that of flour.The folate loss led by boiling,steaming and baking was 11%-22%.2.Three waxy corn varieties and three sweet corn varieties was used to analyze the folate retention of fresh corn during storage and cooking.It found that there were fresh corn contained abundant folates(66.6-152 ?g /100g(FW)at the suitable harvest period(22 days after pollination),with 5-methyltetrahydrofolate as the main folate derivative.The average folate retention rate in waxy corn was 83%after storage at 25 ? for 5 days,which 77% for sweet corn after storage at 4 ? for 3 days.After 14 days of storage at-20 ?,the folate retention in both types of fresh corn averaged 71% and declined to 40%after 120 days.The folate loss caused by boiling was 45% on average,while steaming and microwave heating caused the folate loss of 12% and 15%,respectively.These results provide information for the folate retention in fresh corn after harvest.3.We analyzed the folate content of 64 common foods and beverages in Beijing,including carbohydrates/staples,vegetables,fruits,meat,eggs and milk,and beverages,the total folate content was0.28 ? 129 ?g/100 g fresh weight,with the average of 21.18 ? g/100 g.The folate content in egg yolk and waxy corn was the highest(> 120 ?g/100g),followed by vegetables such as chili,spinach,bean sprouts,stem lettuce,coriander and cauliflower(44-72 ?g /100 g),and the lowest in coca cola(0.28 ?g / 100 g).5-methyltetrahydrofolate is the main folate derivative in various foods.These data will help to estimate daily folate intake and provide dietary recommendations for improving folate status in humans.Through the systematic analysis of folate loss in the storage and processing of wheat and fresh corn products,the main factors affecting folate content were identified.Fresh corn is a good source of folates,with abundant active folate derivatives.And the folate content in commonly consumed food was listed.These results provide a better understanding for folate preservation during household or industrial food preparation,and provide guidance for dietary folate intake for humans.