Effects Of Different Kinds And Debranching Treatment On The Interaction Between Starch And Lipid

Different starch has different gelatinization,crystallization and ordered structure.Starch molecule has helix structure,and can accommodate small molecules of comparable size in the helical cavity,such as lipids.In this study,three different kinds of starches（wheat,corn and rice starch）and normal and waxy corn starch before and after debranching were as the research object,to mixed with different lipids（glycerol,linseed oil and glycerin ester）by rapid viscosity analyzer.The morphology of the mixture was observed,and the crystalline properties and ordered structure of the mixtures were analyzed.The main results and conclusions are as follows:（1）The gelatinization temperature of three different kinds of starches（wheat,corn and rice starch）has no significant change after added lipids,and the type of lipids had no significant effect on the gelatinization temperature of starch either.After the interaction between wheat starch and lipid,the peak viscosity decreased and the thickening ability decreased,while the peak viscosity of corn starch and rice starch did not change obviously.The retrogradation values of wheat,corn and rice starches decreased by 14.5%³5.2%,2.9%¹5.5%and2.3%¹2.1%respectively after added different lipids,which indicated that adding lipids could inhibit the retrogradation of different starches.The gluten viscosity of wheat,corn and rice starch after added linseed oil increased by15.1%,5.8%and 14.9%respectively,and the attenuation value decreased by51.2%,10.0%and 24.7%respectively.The thermal paste stability of wheat starch increased the most.（2）After added lipids,the gel powder surfaces of the three different kinds of starch did not change obviously,all of them were irregular blocks and was not smooth.After added linseed oil,the gel network structure of wheat,corn and rice starch was evenly distributed.The mesh sizes were 18⁴4μm,22⁵1μm and14⁴0μm respectively.The X-ray diffraction peaks of the three starches with the addition of lipids all decreased.The relative crystallinity decreased by21.0%⁴1.3%,28.0%³7.2%and 9.6%²7.7%,respectively.The infrared spectra showed that the absorption peak intensity ratio of 1047 cm^-1/1020 cm^-11 of wheat starch and rice starch was increases after added lipids,their degree of internal order structure increased.The effects of lipid types on the internal ordering of corn starch were different.The ordering of corn starch decreased after added glycerol and linseed oil,while it increased after added glycerin ester.（3）The amylose content of normal corn starch was different from that of waxy corn starch,and the gelatinization characteristics of them were also different.The viscosity range of normal corn starch decreased from 2153³628cP to 25⁶9 cP after debranching treatment.The viscosity range of waxy corn starch decreased from 1475⁴003 cP to 0¹8 cP after debranching treatment.The addition of lipids had no significant effect on the viscosity properties of starch after debranching.Scanning electron microscopy（SEM）observation of starches after debranching treatment and its lipid mixtures showed that normal corn starch was flocculent,irregular protuberance,rough surface and no network structure.The addition of lipid had no significant effect on the morphology of the debranched corn starch gel.The waxy corn starch after debranching treatment showed regular vertical stripe layers,and the spacing between layers was between 15³9μm.The debranched waxy corn starch added glycerol was flocculent,while the debranched waxy corn starch after added linseed oil and glycerin ester showed scattered curly sheets.（4）There was no obvious diffraction peak in the X-ray diffraction pattern of the normal corn starch debranched control group.After debranching treatment,there was a diffraction peak at 2θ=17.2°,and recrystallization occurred.The types of lipid had no significant effect on the recrystallization of the normol corn starch before and after debranching treatment.The waxy corn starvh debranched control group showed a diffuse steamed bread-like peak,and there was no significant change in the waxy corn starch peak type after added lipids.The diffraction peaks of waxy corn starch after debranching treatment also appeared at 2θ=17.2°,and it still existed after added glycerol.While the debranched waxy corn starch added linseed oil or glycerin ester was almost dispersive,and the relative crystallinity decreased by 39.7%and 45.9%respectively compared with the control group.The infrared spectra showed that the absorption peak intensity ratio of 1047 cm^-1/1020 cm^-11 of normol corn starch decreased after debranched,the internal ordering decreases.The ratio of waxy corn starch increases after debranched,and the internal structure of starch rearranged.After added lipids,the retrogradation value of different starches decreased and the retrogradation resistance increased.The addition of linseed oil can improve the heat paste stability of three different kinds of starches,and wheat starch has the greatest improvement.The linear short chain obtained from starch after debranching treatment can recrystallize.The addition of glycerol has no obvious effect on the recrystallization of debranched waxy corn starch.while the addition of linseed oil or glycerin ester can inhibit the internal crystallization rearrangement of debranched waxy corn starch.The addition of three lipids had no effect on the recrystallization of debranched normal corn starch.