title: Comparison of the physicochemical properties and ultrastructure of japonica and indica rice grains.
abstract: The physicochemical properties and ultrastructures of japonica vs indica rice varieties and waxy vs nonwaxy rice varieties were compared. The viscogram values of the indica varieties were significantly higher than those of the japonica varieties. The gelatinization temperatures, breakdown, and setback were significantly lower for waxy than for nonwaxy rice varieties. Japonica rice exhibited lower hardness but higher adhesiveness than indica rice. The air space between individual starch granules was larger for waxy than for nonwaxy rice. The starch granules were compact in japonica rice, while the compound starch granules of indica rice were much smaller than those of japonica rice and were scattered widely in the endosperm. The protein bodies in japonica rice were concentrated near the cell wall, whereas those in indica rice were scattered around amyloplasts. These results suggest that the ultrastructure of rice affects the texture of the cooked product.
authors.affiliation: Research Institute of Cell Engineering, National Institute of Advanced Industrial Science and Technology (AIST, Kansai), 1-18-31, Midorigaoka, Ikeda, Osaka 563-8577, Japan.
authors.forename: Hee-Jin
authors.initials: HJ
authors.lastname: Kang
authors.forename: In-Kyeong
authors.initials: IK
authors.lastname: Hwang
authors.forename: Kyung-Soo
authors.initials: KS
authors.lastname: Kim
authors.forename: Hae-Chune
authors.initials: HC
authors.lastname: Choi
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D005511:Food Handling / Q000379:methods; D006358:Hot Temperature; D008055:Lipids / Q000032:analysis; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D012275:Oryza / Q000737:chemistry* / Q000648:ultrastructure*; D010940:Plant Proteins / Q000032:analysis; D012639:Seeds / Q000737:chemistry* / Q000648:ultrastructure*; D012677:Sensation
chemical_list: D008055:Lipids; D010940:Plant Proteins