Storage sensitivity of ratoon rice: changes in starch structure and physicochemical properties

Ratoon rice (RR), a second-season crop regenerated from the axillary buds of rice stems after harvesting the main crop (MC), is a vital source of high-quality rice and enhances the overall paddy field yield. However, its starch structure and physicochemical stability during storage remain unclear. This study examined the effects of 12-month storage on the composition, starch structure, and physicochemical characteristics of RR and MC. Storage increased the proportion of A-chains in amylopectin, while reducing the amylose and long-chain amylopectin contents, starch granule size, crystalline structures, and short-range ordered structures. These structural changes led to a higher gelatinization temperature range and peak and cool paste viscosities, but lower gelatinization temperature and enthalpy. Moreover, RR was found to exhibit greater sensitivity to storage than MC, with more pronounced changes in its amylose, protein, and fat contents, as well as the A-, B1-, and B3-chain proportions of amylopectin, starch granule size, relative crystallinity, and R 1047/1022 . Consequently, RR exhibited greater changes in its thermal (To, Tp, Tc, and ΔT) and pasting (peak, hold, breakdown, cool, and consistency viscosities) properties. These results highlight the lower storage stability of RR compared to MC, thereby indicating the requirement for targeted preservation strategies. •The effects of storage (12 months) were investigated for RR and MC specimens. •Crystallinity and starch granule size decreased after 12 months of storage. •Storage increased the A-chain content, but decreased the B1–B3 chain, amylose, and protein contents. •RR exhibited greater changes in its thermal and pasting properties. •RR exhibited a lower storage stability than MC.