Effects Of Co-milling With Tea Polyphenols On The Physicochemical Properties And Digestibility Of Starch

Starch is not only the main source of carbohydrates,but also the main cause of postprandial hyperglycemia.After eating starch foods,the fast digestion of starch rapidly decomposes into glucose,which increases the risk of obesity and diabetes,and restricts the development of starch food industry.However,tea polyphenols can inhibit the activity of alpha amylase and alpha glucosidase,and slow down the hydrolysis rate of starch.Therefore,the purpose of this study is to provide theoretical basis for the development of functional starch through the slow release of tea polyphenols,the reduction of the digestion rate of starch and the increase of the content of resistant starch,so as to control the increase of postprandial blood sugar.In this paper,potato starch,corn starch and high amylose corn starch were used as raw materials to prepare three kinds of tea polyphenols-starch co-milled mixture.The effect of co-milled with tea polyphenols on the physicochemical properties and in vitro digestion characteristics of starch were investigated.As well as in vitro release regularity of tea polyphenols.The experimental results showed that tea polyphenols had the greatest influence on the crystalline structure of potato starch,while the crystalline structure of corn starch and high amylose corn starch was relatively small,and the grinding time was inversely proportional to the degree of crystallinity.It had little effect on the crystallinity of starch when the proportion of tea polyphenols/starch is below 1:10.SEM analysis showed that the particle diameter of tea polyphenols-starch co-milled mixture was increased.Compared with the original starch granules,the particle surface was rough and the particle shape was irregular.FT-IR analysis shows that there is an interaction between starch and tea polyphenols.The TG analysis showed that the thermal stability of the tea polyphenols-potato starch co-milled mixture is better than the tea polyphenols and the other two kinds of tea polyphenols-starch co-milled mixture.The digestion experiment showed that tea polyphenols can affect the digestion of starch in a certain extent.Tea polyphenols can improve resistant starch digestibility with the increase of the ratio of tea polyphenols.The in vitro digestibility of co-milled mixture with a proportion of 1/10 was the lowest in vitro,and the best anti digestibility was 60.11%.The content of digestive function starch showed that tea polyphenols can improve the resistant starch content of corn starch and high amylose corn starch,while the content of slow digestible starch decreased to some extent.The proportion of resistant starch in the potato starch-tea polyphenol co-milled mixture proportion of 1/10 was the highest,which was 36.53%.According to the evaluation of in vitro release,the cumulative release was related to the ratio of tea polyphenol/starch.The higher ratio of tea polyphenols in co-milled mixture,the higher cumulative release rate is.Potato starch-tea polyphenol co-milled mixture(1/10)has strong sustained release properties of tea polyphenols.These released tea polyphenols can inhibit the activity of alpha amylase and alpha glucosidase,so as to control the purpose of increasing postprandial blood sugar.