title: Impact of postharvest drying conditions on in vitro starch digestibility and estimated glycemic index of cooked non-waxy long-grain rice (Oryza sativa L.).
abstract: BACKGROUND
  Wet paddy needs to be dried to reduce its moisture content after harvesting. In this study, effects of postharvest drying condition on in vitro starch digestibility and estimated glycemic index of cooked rice (Oryza sativa L.) were investigated. Varying drying conditions, i.e. hot-air drying at 40, 65, 90 and 115 °C, and sun drying were applied to raw paddy. After husking and polishing, polished grains were cooked using an electric rice cooker. Cooked samples were analyzed for their moisture content and amount of resistant and total starch. Five samples in both intact grain and slurry were digested under simulated in vitro gastrointestinal digestion process. The in vitro starch digestion rate was measured and the hydrolysis index (HI) and estimated glycemic index (eGI) were calculated.
  
  
  RESULTS
  Cooked rice obtained from hot-air drying showed relatively lower HI and eGI than that obtained from sun-drying. Among samples from hot-air drying treatment, eGI of cooked rice decreased with increasing drying temperature, except for the drying temperature of 115 °C. As a result, cooked rice from the hot-air drying at 90 °C showed lowest eGI.
  
  
  CONCLUSIONS
  The results indicated that cooked rice digestibility was affected by postharvest drying conditions. © 2016 Society of Chemical Industry.
authors.affiliation: Graduate School of Horticulture, Chiba University, Matsudo 271-8510, Japan.|School of Agro-Industry, Mae Fah Luang University, Chiang Rai 57100, Thailand.
authors.forename: Natthawuddhi
authors.initials: N
authors.lastname: Donlao
authors.affiliation: Graduate School of Horticulture, Chiba University, Matsudo 271-8510, Japan.
authors.forename: Yukiharu
authors.initials: Y
authors.lastname: Ogawa
mesh_terms: D003296:Cooking; D018556:Crops, Agricultural / Q000737:chemistry / Q000378:metabolism; D004040:Dietary Carbohydrates / Q000032:analysis / Q000378:metabolism; D004063:Digestion; D005511:Food Handling; D063427:Food Quality; D057141:Food, Preserved / Q000032:analysis; D038321:Glycemic Index; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D006868:Hydrolysis; D007564:Japan; D007700:Kinetics; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D012275:Oryza / Q000737:chemistry* / Q000378:metabolism; D012639:Seeds / Q000737:chemistry* / Q000378:metabolism; D013213:Starch / Q000032:analysis / Q000378:metabolism*; D014867:Water / Q000032:analysis
chemical_list: D004040:Dietary Carbohydrates; D014867:Water; D013213:Starch
keywords: cooked rice; glycemic index; postharvest drying; starch; temperature