The impact of milling degrees on rice quality using simultaneous rheology and FTIR techniques: Focus on starch...

Moderate milling can find a balance between the nutrition and cooking qualities of rice. The study investigated milling degree (MD) on rice quality and digestive properties and the indirect association with starch structure using simultaneous rheology and FTIR, X-ray diffraction, and small angle X-ray scattering. As MD increased, rice flour became easily pasted. The water absorption and volumetric expansion increased. The maximum digestibility of slowly digested starch improved, while resistant starch and t_2start decreased by 36.33 % and 37.50 % (MD4), respectively. MDs resulted in varying contents of the aleurone layer, indirectly causing changes in starch structure during heating. Starch formed hydrogen bonds during heating, with a sustained increase in the degrees of order and double helix at higher MD. The crystalline and helical structures were disrupted and rearranged to variable degrees. The moderate milling could improve cooking quality. It serves as a potential guide for production of moderately milled rice.