Preparation Of Waxy Rice Starch-β-Glucan Complexes By Ball Milling And Investigation Of Their Physicochemical And Digestive Properties

Starch is a major source of energy in the human diet,however the rapid digestion of starch often leads to a rapid rise in blood sugar in the body,increasing the risk of diseases such as obesity and hyperglycaemia and greatly limiting its use.Oatβ-glucan has the ability to inhibit the activity of amylase and reduce the digestibility of starch.In addition,ball milling treatment has received attention from researchers as a green and efficient physical modification technique.Therefore,in this thesis,the effect of ball milling treatment on the physicochemical properties and structure of waxy rice starch was investigated using waxy rice starch as raw material.The effects of ball milling time and oatβ-glucan addition on the physicochemical and digestive properties of the starch-β-glucan complexes were investigated by scanning electron microscopy,infrared spectroscopy,Raman spectroscopy,X-ray diffraction,differential scanning calorimetry and in vitro digestion simulation.Molecular docking was used to elucidate the intermolecular interactions between the two compounds.The results were used to develop slowly digested waxy rice products with low glycaemic response levels.The main findings were as follows:1.After the ball milling treatment,the crystallinity of waxy rice starch did not change,while the crystallinity decreased from 28.52%to 7.23%,the granular integrity of the starch was damaged,cracks appeared,the particle size distribution tended to increase and the short-range ordered structure was severely damaged.Compared to the untreated starch,the water absorption index increased from 2.15 to 7.31 g.g^-1 at 80 min of ball milling,cold water solubility and swelling increased significantly,starch pasting characteristics parameters all showed a significant decrease,enthalpyΔH decreased from 9.33 to 1.79 J.g^-1 and pasting degree increased significantly.The polarization cross characteristics of the starch diminished with increasing treatment time.2.The optimum ball milling time for the waxy rice starch-β-glucan complex was 60 min,with the maximum resistant starch content of 35.92%.With the increase of ball milling time,the surface of its complex particles became rough,the more irregular the shape of the particles,and the phenomenon of agglomeration and agglomeration appeared.The IR spectral results showed that there was no significant change in the individual absorption peaks and no new chemical bonds were formed.The ball milling treatment caused the oatβ-glucan to be inlaid or attached to the waxy rice starch by hydrogen bonding.The short-range orderliness of the complex gradually decreased,the content of the double helical structure decreased and the content of the amorphous region increased significantly.3.As the amount of oatβ-glucan added increases,the particle size of the starch-β-glucan complex increases significantly,and the swelling and solubility decrease significantly.In addition,ball milling leads to the disruption of the crystalline regions of the starch granules,resulting in the transformation of the starch from a semi-crystalline structure to an amorphous state,resulting in the formation of a new low or disordered crystal structure.Quantum chemistry and molecular docking suggest that oatβ-glucan interacts with waxy rice starch through hydrogen bonding,thereby inhibiting starch digestion and providing some theoretical basis for the development of healthy starches and products.