title: Differences in physicochemical properties of kernels of two rice cultivars during grain formation.
abstract: BACKGROUND
  Rice varieties with similar apparent amylose content may have different grain qualities. The development of rice quality is a dynamic process that occurs with the formation of rice kernels. In this study, physicochemical properties during the grain formation period were investigated to interpret differences in grain quality between two non-waxy rice cultivars, Wuyujing3 and 30you917, with similar apparent amylose content.
  
  
  RESULTS
  There were significant differences in dynamic changes in 1000-grain weight, amylose content and pasting and thermal properties during grain formation of the two cultivars. The difference in their apparent amylose contents from 5 days after anthesis (DAA) to 15 DAA was significant, except in the late grain-filling stage. Wuyujing3 showed a slower increase in 1000-grain weight than 30you917 from 10 to 25 DAA. The transition temperatures (T(o), T(p) and T(c)) of developing grain flour of Wuyujing3 were higher than those of 30you917 during the grain formation period. Wuyujing3 showed greater stickiness (higher breakdown and peak viscosity and lower positive setback) than 30you917 according to Rapid Visco Analyser (RVA) profiling.
  
  
  CONCLUSIONS
  The results suggested that the differences in cooking and eating quality parameters of the two mature rices were determined by the differences in grain filling and the dynamic changes in the main rice quality components such as amylose content, grain weight and differential scanning calorimetry and RVA properties, which will help cultivators understand the physical basis of rice quality development.
authors.affiliation: Key Laboratory of Ecological Agriculture of Ministry of Agriculture, South China Agricultural University, Guangzhou, China. caiyixia@scau.edu.cn
authors.forename: Yixia
authors.initials: Y
authors.lastname: Cai
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Kunzheng
authors.initials: K
authors.lastname: Cai
mesh_terms: D000688:Amylose / Q000032:analysis; D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D005433:Flour; D005511:Food Handling; D005782:Gels; D012275:Oryza / Q000737:chemistry* / Q000254:growth & development*; D011786:Quality Control; D012639:Seeds / Q000737:chemistry* / Q000254:growth & development*; D013045:Species Specificity; D013997:Time Factors; D044366:Transition Temperature; D014783:Viscosity
chemical_list: D005782:Gels; D000688:Amylose