Preparation,Structure And Properties Of Highland Barley Starch Modified By OSA With Frozen Ball Milling

As a kind of multigrain grain,highland barley has become a research hotspot.In order to further develop highland barley products and expand the way of deep processing highland barley starch,on the basis of previous studies,this study selected octenyl amber anhydride(OSA)modified highland barley starch,and the use of frozen ball milling to cooperate with OSA modified highland barley starch.The differences between the cooperative modification of frozen ball milling and the traditional modification methods in the OSA degree of substitution,the position of substitution reaction and other structural changes and the performance of modified starch were compared.At the same time,OSA modified highland barley starch as emulsifier was used to prepare nano emulsion to carry lycopene and other nutrients,and to enhance the stability of the emulsion and improve the protection efficiency of nutrients were explored.The main research results are as follows:1.The grain morphology of highland barley starch was significantly changed by frozen ball milling,and the surface of starch granules became rough,with cracks and holes.The grain size of barley starch increased after frozen ball milling mainly due to the damage of starch particles,the roughness of the original smooth surface,and the agglomeration of fine starch particles after frozen ball milling for a certain time.The amylose content of barley starch decreased after frozen ball milling.At the same time,the crystal structure of starch was damaged by freezing ball milling,and the crystallinity was decreased.The longer the milling time,the lower the crystallinity was,but the crystallinity of starch was not affected.2.Frozen ball milling could promote the modification of highland barley starch with octenylsuccinic anhydride.When the frozen ball milling time reached 40 min,the degree of substitution of OSA modified highland barley starch was 1.32 times that of traditional modification methods.Frozen ball milling treatment did not significantly destroy the long-term order of OSA highland barley starch.On the contrary,the crystallinity of OSA modified starch pretreated by frozen ball milling increased compared with that of original highland barley starch after OSA modification,and its short-term order decreased with the extension of frozen ball milling time.Frozen ball milling treatment reduced the gelatinization temperature of OSA starch,improved its solubility,swelling,gelatinization transparency and freeze-thaw stability,and increased the content of resistant starch(RS).3.Compared with the traditional modification methods,the frozen ball milling pretreatment significantly improved the emulsification performance of OSA modified highland barley starch.The starch emulsion did not show obvious stratification after 15 days of storage at room temperature,and still maintained good stability.The three-dimensional reticular space structure formed in the emulsion system was more tightly intertwined and more stable.The frozen ball milling pretreatment increased the absolute value of Zeta potential of starch emulsion,and increased the electrostatic repulsion force between emulsion droplets.4.Compared with traditional modification methods,the nano emulsion system prepared by frozen ball milling/OSA modified highland barley starch could better protect lycopene and effectively store lycopene.