The Relationship of Cultivars, Structures and In Vitro Digestibility of Chinese Chestnut (Castanea henryi) Starches Treated with Low-Voltage Electrostatic Field Technology

Low-voltage electrostatic field (LVEF) treatment is an emerging food preservation technology that exploits the physical effects of electrostatic fields; however, its mechanisms of action in nut crops remain poorly understood. This study investigated changes in starch structure, processing properties, and in vitro digestibility in five chestnut cultivars (Castanea henryi) from different regions of China (Chushuhong, Changmangzi, Youzhen, Hongzhenzi, and Huangzhen) following refrigeration treatment (RT) and LVEF treatment. LVEF increased the crystallinity and molecular order of chestnut starch. It also generally reduced free water content, peak viscosity (PV), breakdown viscosity (BV), and setback viscosity (SV), while increasing water-holding capacity. In addition, LVEF enhanced the resistance to shear and retrogradation, thereby improving starch processing performance. The TPA results showed that LVEF improved the textural properties of chestnut starch gels, supporting their suitability for gel-based foods. The responses varied among the cultivars. Compared with RT, LVEF reduced the particle size and free water content of Chushuhong starch by 19.56% and 18.41%, respectively. Chushuhong also exhibited the largest increase in crystallinity (31.34%), while the bound water content of its starch gel increased by 13.70%, indicating stronger responsiveness to LVEF. Overall, LVEF improved the processing performance of chestnut starch, although varietal differences in the responses were observed. LVEF-treated Chushuhong and Changmangzi starches exhibited favorable processing properties, indicating their suitability for developing processed chestnut products. Meanwhile, their starches exhibited faster enzymatic hydrolysis rates under in vitro conditions. These findings provide a basis for applying LVEF in developing chestnut starch-based products.