Effect of insoluble glucan on self-assembly kinetics and physicochemical properties of starch microparticle (SMP)

This study aimed to investigate the impact of insoluble glucan on the self-assembly kinetics and physicochemical attributes of starch microparticles (SMPs). It was found that the inclusion of insoluble glucans (SMP-ISG) significantly accelerated both the formation and crystallization processes, demonstrating a rate approximately 1.5 times faster compared to SMPs without insoluble glucans (SMP-SG). This acceleration in kinetics was attributed to the presence of insoluble long chains, which facilitated molecular aggregation and crystal growth. Additionally, SMP-ISG displayed changes in particle size (0.74 μm) and relative crystallinity (19.9%) when compared to SMP-SG (0.62 μm and 17.7%, respectively) suggesting that insoluble glucans contribute to the enhancement of both size and crystallinity, which support the hypothesis of their role in molecular aggregation and crystal nucleation. However, despite these beneficial effects, SMP-ISG showed increased susceptibility to agglomeration, which compromised the stability of the colloidal system. During the formation of SMP-ISG, alignment with insoluble glucans facilitated the creation of more stable double-helix structures, leading to elevated enthalpy and transition temperatures. In SMP-ISG, the digestion rate was reduced due to a higher content of resistant starch, whereas SMP-SG exhibited a higher content of slowly digestible starch. Consequently, it is possible to customize the properties of SMPs by precisely controlling the amount of insoluble glucans during SMP formation, thereby broadening their utility in various food and industrial applications.