Formation Of Starch-Lipid Complexes In Starch-Oil System And Its Effect On The Oil Absorption Of Starch

The interaction between starch and lipid have been extensively studied and have important implications for the functional properties and nutritional value of starch.The interaction between starch and lipid includes: the formation of starch-lipid complexes by hydrophobic interactions between starch and fatty acids or fatty acid esters;and the adsorption of triglycerides by starch is shown by the oil absorption of starch.Whether these two interactions affect each other has not been studied.Therefore,the purpose of this paper is to investigate formation of starch-lipid complexes in starch-oil system and its effect on the oil absorption of starch,divided into two aspects: the effect of triglycerides on the formation of starch-fatty acid complexes,and the effect of starchfatty acid/fatty acid ester complexes on the oil absorption of starch.The details are as follows.Firstly,the effect of triglycerides on the formation of starch-fatty acid complexes was investigated.The fatty acids included lauric acid(C12:0),myristic acid(C14:0),palmitic acid(C16:0)and stearic acid(C18:0).The rapid visco analyzer(RVA),X-ray diffractometry(XRD),differential scanning calorimetry(DSC)and confocal laser scanning microscopy(CLSM)analyses confirmed the formation of starch-fatty acid complexes but the starch-triglyceride complex was not detected.The addition of triglycerides promoted formation of starch-palmitic acid and starch-stearic acid complexes,which might be due to more leached amylose induced by triglycerides.However,triglycerides inhibited the formation of starch-lauric acid complexes and starch-myristic acid complexes,which may be related to the higher affinity of lauric acid and myristic acid for triglycerides.Secondly,the effect of starch-fatty acid/fatty acid ester complexes on oil absorption of starch was investigated.The fatty acids included lauric,myristic,palmitic and stearic acids,and the fatty acid esters were glyceryl monolaurate and glyceryl monostearate.The complexes were characterized by X-ray diffractometry and their complex index were determined,followed by determination of oil absorption by centrifugation and oil absorption by frying.It was found that the starch-lipid complexes could significantly reduce the oil absorption of starch and the complexes with higher complex index had lower oil absorption.The starch-palmitic acid complex had the lowest oil absorption for frying,with a reduction of 14.06 g/100 g compared to gelatinized starch.Finally,the possible application was explored.The starch-palmitic acid complex with the lowest oil absorption was added to fried instant noodles replacing 30% starch.The complexes were characterized by X-ray diffractometry and the noodle structure was observed by scanning electron microscopy.The moisture content after steaming and oil absorption after frying were then determined,and the final product was subjected to starch digestion and sensory analysis.The results showed that the oil absorption of fried instant noodles with starch-palmitic acid complex decreased by 6.52g/100 g,while the slow-digesting starch and resistant starch increased by 6.82% and4.87%,respectively.And adding starch-palmitic acid complex had little effect on the edible quality of fried noodles.It provides reference for the development of fried food with multiple health benefits.