Formation Mechanism Of Starch-fatty Acid-protein Ternary Complex And Its Effect On Starch Functional Properties

Starch,lipids,and proteins are nutrient components of many foods and a major source of calories in the human diet.During food processing,these nutrients change,and often the complex interactions between them determine the quality,nutrition and organoleptic properties of the food,so this topic focuses on the interaction between the three components of the real food system.And the formation of complexes to expand.The aim of the present study was to characterize the multiscale structures of ternary complexes of a model system of starch,fatty acid(FA),and ?-lactoglobulin(?LG)prepared using a Rapid Visco Analyzer(RVA).The addition of ?LG to starch-lauric acid or starch-oleic acid RVA pastes resulted in the increased intensity or occurrence of a new viscosity peak during cooling when the RVA protocol was repeated.The viscosity peak was attributed to the formation of starch-?LG-FA complexes.Differential scanning calorimetry(DSC)results showed clearly that the starch-?LG-FAs complex was formed as gelatinized starch was cooled in the presence of PLG and FAs.The results of Raman,FTIR,and X-ray diffraction analyses showed that starch can interact with ?LG and FAs to form a ternary V-type crystalline complex,which had a greater short-range molecular order and higher relative crystallinity compared with those of the binary starch-FA complex.The effects of chain length and degree of unsaturation of fatty acids(FAs)on structure and in vitro digestibility of starch-protein-FA complexes were investigated in model systems.Studies with the Rapid Visco Analyser(RVA)showed that the formation of ternary complex resulted in higher viscosities than those of binary complex during the cooling and holding stages.The results of Differential Scanning Calorimetry(DSC),Raman and X-ray diffraction(XRD)showed that the structural differences for ternary complexes were much less than those for binary complexes.Starch-protein-FA complexes presented lower in vitro enzymatic digestibility compared with starch-FAs complexes.We conclude that shorter chain and lower unsaturation FAs favor the formation of ternary complexes,but decrease the thermal stability of these complexes.FAs had a smaller effect on the ordered structures of ternary complexes than on those of binary complexes,and little effect on enzymatic digestibility of both binary and ternary complexes.The present study provided insights into the structure of a model starch-protein-fatty acid complex as an example of what might occur during food processing.