Effect of High-Pressure Microfluidization on the Microstructure, Physicochemical Properties, and Digestibility of the Different Particle Sizes of Potato Starch

Potato starch (PS) is widely used in the food industry, but its uncontrolled paste consistency and poor film properties greatly limit its utilization. To expand its application, PS is separated into small- (PS-S), medium- (PS-M), and large- (PS-L) fractions and modified by "high-pressure microfluidization" (HPM). The effect of HPM on the microstructure, physicochemical properties, and digestibility of fractionated PS is investigated. Results show that the mechanical forces produced by HPM(50-150 MPa) can break PS molecules and enhance digestion rate with increasing pressure. Meanwhile, the relative crystallinity (RC) of HPM(150 MPa)-modified PS-L, PS-M, and PS-S decreases by about 29.23%, 15.40%, and 9.33%, respectively, relative to the RC of native fractionated PS. The changes in 1047/1022 and Delta H values in the three fractions show similar trends. Thus, the changes in microstructure of HPM-modified PS-L show more considerable than that of PS-S. Compared with the native ones, the final viscosity of HPM(150 MPa)-modified PS-L, PS-M, and PS-S decreases by about 61.86%, 41.61%, and 35.70%, respectively, and the setback value increases to 379.67, 479.67, and 493.00 cp, respectively. These results indicate that HPM-modified PS-S has a higher tendency to form edible films than PS-L. Therefore, HPM-modification may expand the industrial application of fractionated PS. High pressure microfluidization (HPM) reduces the ordered structure of potato starch, increases the setback value of starch paste, and enhances rapidly digested starch content. Meanwhile, the changes of these properties in large starch are much more remarkable than small ones.image