Effect of Ball-Milling on Starch Crystalline Structure, Gelatinization Temperature, and Rheological Properties: Towards Enhanced Utilization in Thermosensitive Systems

Starch's crystalline structure and gelatinization temperature might facilitate or hinder its use. Ball milling has frequently been mentioned in the literature as a method for reducing starch size and as a more environmentally friendly way to change starch, such as by increasing surface area and reactivity, which has an impact on other starch properties. In this study, starch samples were milled for varying durations (1, 5, 10, 20, and 30 h) and at different starch-to-ball mass ratios (1:6 and 1:20). Microscopy and XRD revealed that prolonged milling resulted in effective fragmentation and a decrease in crystallinity of the starch granules. Increasing milling times resulted in an increase in amylose content. Rheology and thermal studies revealed that gelatinization temperatures dropped with milling duration and that viscosity and thixotropy were directly influenced. The samples milled for 10, 20, and 30 h at a ratio of 1:20 were the most fragmented and upon drying formed a transparent film at ambient temperature, because of the lower gelatinization temperature. Starch ball milling could lead to the use of this material in thermosensitive systems.

Automated summary

The crystalline structure and gelatinization temperature of starch can impact its usability. Ball milling has been proposed as an eco-friendly method to modify starch by reducing its size and increasing reactivity. This study examined the effects of milling duration and starch-to-ball mass ratio on starch properties. Prolonged milling resulted in the fragmentation and decrease in crystallinity of starch granules. Additionally, amylose content increased with milling time, and gelatinization temperature and rheological properties were influenced. The most fragmented samples, milled for 10, 20, and 30 hours at a ratio of 1:20, formed transparent films at ambient temperature due to lower gelatinization temperature. Starch ball milling could enable the use of starch in thermosensitive systems.