Experimental warming under field conditions alters starch multi-structure and flour and starch functionality of late-season indica-japonica hybrid rice in southern China

Abstract

IntroductionThe effects of climate warming on starch multi-structure and flour and starch functionality of late-season indica-japonica hybrid rice (IJHR) in double-rice cropping systems are still unclear to date.MethodsA 2 years field warming experiment was conducted by using free-air temperature increase facilities with an IJHR cultivar (Yongyou1538). The starch multi-structure and flour and starch functionality of IJHR were determined.ResultsExperimental warming (on average 2.1°C over the 2 years) reduced the amylose content and increased the amount of short amylopectin branch-chains (degree of polymerization 6–12), possibly due to decreased granule-bound starch synthase activity and increased starch-branch enzyme activity. Additionally, the protein content, starch granule diameter, relative crystallinity, and swelling power of IJHR were enhanced by experimental warming. The changes in rice components and starch multi-structure under warming conditions resulted in high peak viscosity, breakdown, pasting temperature, gelatinization temperatures and enthalpy and low setback of rice starch and high peak viscosity and pasting temperature and low setback of rice flour.ConclusionOur results indicated that climate warming might improve the pasting viscosities and enhance the thermal stability of late-season IJHR.