Changes Of Bamboo Leaves Flavonoids In Flour System Caused By Thermal Treatment

With the diversified development of wheat flour food,there are more and more functional foods on the market.They are also very popular.Bamboo leaves have a lot of nutrients,such as flavonoids.And flavonoids is rich in bamboo leaves,which has significant biological activities,and it also has increasingly applied in food field.Bamboo leaves flavonoids as the main research object,using the method of process tracking to research its change in different thermal process,and the change after applied to the flour system.In addition,we had discussed about the influence of sucrose,salt and baking soda for flavonoids in the processing,including the content and the total antioxidant capacity.At last we used GC-MS to analyze the untreated and the treated component change,mainly for acids.The experimental results showed that,in the three thermal treatment methods:microwave,baking and steaming,the steaming showed significant reduction in bamboo-leaves-flavonoids(40%-70%);followed by baking,with this treatment,Acidosasa edulis had the highest loss rate,all other processing is between 16%-33%;and the reduction caused by microwaves is less than 30%.Among the four bamboo species:Acidosasa edulis(AE),Phyllostachys heterocycla(PH),Dendrocalamopsis oldhami(DO),and Pleioblastus amarus(PA),DO had minimal variation on the content of flavonoids.AE flavonoids decreased significantly in baking processing,its loss rate was 69%;the loss rate of PH bamboo-leaves-flavonoids was 71%;extract of PA bamboo-leaves-flavonoids had larger changes after heat treatment,.lost about 30%-40%;and DO’s change was small,the maximum loss was 34%with steaming.With different processing,each species showed the characteristic of regular,it is associated with flavonoids’ type and quantity.AE and PH flavonoids affected by additives(sucrose,salt,baking soda)have difference in the thermal processing of flour products.In AE flour products,with the rising of sucrose,flavonoids content decreased first and then increased,when the amount of sucrose was 5g/100g,the lowest content of flavonoids;increased with the amount of salt,flavonoids continue to lower,as salt was 1g/100g,bring the significant reduction on flavonoids;while with the addition of baking soda to increase,the flavonoid content was unregular,the optimum dosage is 1g/100g.In PH flour products,sucrose and sult had no significant effect on the amount of flavonoids;baking soda made flavonoids significant decline,variation trend is similar with AE.Three kinds of additives and baking that affected the total amount of flavonoids,while bring the type and content of acids.At the same time,we found citric acid,linoleic acid,inositol and etc.new substances during processing,these substances have contribution on the taste,flavor of food and biological activity.In addition,we found that the antioxidant capacity is associated with additives,AE and PH had the same change regular.When added with sucrose and baking soda,antioxidant capacity significantly increased;while plus salt treatment,total antioxidant capacity had not much difference.The study should be very useful in promoting fine production of bamboo leaf flavonoid as food additives.