| Yam,as a kind of crops with the same origin of medicine and food,has advantages of high nutritional value,high yield and rich variety,and its main ingredient is starch.Meanwhile,oat?-glucan is a kind of soluble non-starch polysaccharide,which plays an important role in intestinal flora of human body.In this paper,the physicochemical characteristics and digestive properties of different kinds of yam starch were studied.According to the content of resistant starch,Tiegun yam starch was selected.The blends of Tiegun yam starch and oat ?-glucan were further prepared by rapid visco analyser to study its physical and chemical properties,digestive properties and antioxidant activity.The main research contents and conclusions are as follows:1.Study on physicochemical characteristics and digestive properties of starch of different varieties of yamUsing Purple yam,Tiegun yam and Vegetable yam as raw materials,the starch of three different varieties of yam was extracted by alkali extraction method,and the chemical composition,granule properties,crystal types,gelatinization characteristics,viscosity properties and in vitro digestibility of starch of different varieties of yam were studied.The physicochemical characteristics and digestibility of different kinds of yam starch were studied.It was found that Tiegun yam starch was the best and the content of resistant starch was the highest.2.Preparation and physicochemical properties of yam starch/oat ?-glucan blendsIn order to study the effect of oat ?-glucan on yam starch,the yam starch/oat ?-glucan blends were prepared by rapid visco analyzer.The gelatinizing properties,thermal properties,rheological properties and digestive properties of the blends were investigated.The results showed that the gelatinization enthalpy ?H,viscosity and regeneration value of blends was significantly decreased and the gel structure was weakened with the addition of oat ?-glucan.Infrared spectrum analysis showed that yam starch and oat ?-glucan had no covalent binding and mainly through hydrogen bond.X-ray diffraction results showed that the gelation changes the crystal type and decreased the relative crystallinity.In addition,scanning electron microscopy showed that the pore size of yam starch/oat ?-glucan blends decreased with the increase of oat ?-glucan content.This study could provide theoretical basis for developing oat?-glucan/starch based food.3.Digestibility and functional properties of yam starch/oat ?-glucan blendsThe digestive properties and antioxidant activity of yam starch/oat ?-glucan blends were studied.The addition of oat ?-glucan increase the content of resistant starch,and decreased the digestibility,with the highest value was 49.24±0.16%.Meanwhile,the antioxidant activity of the blends was studied in vitro.The results showed that the yam starch/oat ?-glucan blends had DPPH radical scavenging ability,hydroxyl radical scavenging ability,reducing ability and total antioxidant ability.Therefore,the yam starch/oat ?-glucan blends have certain antioxidant properties.The yam starch/oat ?-glucan blends could be used as a potential resource in functional foods. |
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