With increasing interests on health issues, whole grains are getting focus with their various beneficial effects along with unique characteristics. Studies on whole grains, however, are mostly focused on whole wheat grains, no systematic researches on whole rice grain has been attempted. In this study, we tried to characterize the starches in whole rice grain including morphology, molecular weight distribution and its side chain structures for further application. Early harvested whole rice grains, named as green whole rice (GWR) was coarsely grounded and starch fraction was separated through alkaline steeping method and dried for the analysis. Morphology of starch particles of GWR was investigated with scanning electron microscopy (SEM) and no significant differences was observed compared to the control rice starches. Pre-treatments such as dehulling and steaming also did not affect overall shape of starches in rice. Molecular weight distribution of GWR starch was analyzed with gel permeation chromatography (GPC) and compared with normal rice starch. GPC analyses revealed that the relative ratio of higher molecular weight fractions in GWR was significantly higher than normal rice. In addition, side chain structures of amylopectin molecules in GWR starch was analyzed with high performance size exclusion chromatography (HPSEC). The average number of DP in GWR was shorter with higher ratio of shorter side chain fractions than normal rice starch. These findings on GWR starch would be useful basement for following research and application of green whole rice.

• Joong-Hyuck Auh(Department of Food Science and Technology, Chung-Ang University, Korea)
• Myong Zun Kim(Department of Food Science and Technology, Chung-Ang University, Korea)
• Byeong Deug Choi(Department of Food Science and Technology, Chung-Ang University, Korea)
• Jung-Yoon Kim(Department of Food Science and Technology, Chung-Ang University, Korea)