Preparation Of Starch-lipid Complex Assisted By Wet Grinding And Its Mechanism Analysis

The starch-lipid complexes could reduce the solubility and swelling power of the starch and delay its gelatinization,thus affecting the quality of the final products.Additionally,grinding treatment has been shown to play a pivotal role in enhancing the properties of starch.While dry grinding has been the predominant method for starch modification in previous research,the effects of wet grinding have been less explored.Water not only served as an effective starch plasticizer but also enhanced grinding uniformity.Therefore,in this paper,the preparation of starch-lipid complexes was assisted by wet grinding.The effects of wet grinding on the structure and properties of starch-lipid complexes were analyzed,and its formation mechanism was discussed.The main conclusions were as follows:(1)After wet grinding for 2.5-5 min,the surface of starch granules became rough,the polarized cross of starch granules decreased,the crystallinity,particle size and viscosity continued to decrease,and solubility and swelling force continued to increase.With the increase of wet grinding time,the order of starch molecules increased,and starch granules occurred the rearrangement of the starch molecules.After wet grinding for 15-20 min,the polarized cross of starch granules was severely damaged.As more water molecules entered into the starch granules,the crystal structure was significantly disrupted,leading to a reduction in particle size,viscosity,gelatinization temperature,gel system stability,and an increase in solubility.(2)A certain amount of lauric acid(LA)was added to corn starch,and the preparation of starch-lipid complexes was assisted by medium-temperature wet grinding.The changes in starch structure and properties before and after adding lauric acid were analyzed.The crystallinity was significantly reduced,and starch molecules were continuously hydrated and even partially gelatinized.This promoted the release of more amylose chains to participate in starch-lipid complex formation and facilitated LA entry into the amylose spiral cavity,resulting in an increased formation of starch-lipid complexes.With the wet grinding time extended to 30 min,the amount of starch-lipid complexes reached the maximum.It could be seen that proper medium-temperature wet grinding(30 min)was conducive to the formation of starch-lipid complexes.(3)The preparation of starch-lipid complexes was assisted by high-temperature wet grinding.The effects of the two treatment methods of compound before wet grinding(C/WG)and wet grinding before compound(WG/C)on the structure and properties of starch-lipid complexes were analyzed.The X-ray diffraction patterns of Control,CS-WG/C and CSC/WG samples showed V-type crystal characteristic diffraction peaks.At the same time,the starch after wet grinding showed a higher composite index,intensity and ΔH’.In addition,WG/C was more beneficial to forming more starch-lipid complexes.CS-WG/C-10 had the highest content of resistant starch(36.32%)and had the lowest solubility(3.9%)and swelling force(7.8 g/g).It could be seen that proper high-temperature wet grinding treatment could promote the formation of starch-lipid complexes.