title: Effect of parboiling on the formation of resistant starch, digestibility and functional properties of rice flour from different varieties grown in Sri Lanka.
abstract: BACKGROUND
  Hydrothermal treatment used in parboiling could induce formation of novel starch properties having potential food applications. In the current work, functional, digestible and retrogradation properties of flour from non-parboiled and steamed parboiled six rice varieties with high amylose content of around 30% but differing in length and width ratio were investigated and compared.
  
  
  RESULTS
  The parboiling process reduced swelling volume and amylose leaching in all tested varieties. Among the varieties studied, the resistant starch content ranged from 1.6% in AT 306 to 0.46% in BG 357. Parboiling reduced the resistant starch content in AT 306 by about 50%, but it did not significantly affect the resistant starch content of the other varieties. The amylose-lipid complex remained unchanged after parboiling. Amylopectin retrogradation was not observed in parboiled rice. Amylose retrogradation was not seen except for AT 306. Pasting behaviour of parboiled rice flours showed high pasting stability and low setback. Flours were more susceptible to enzymatic hydrolysis after parboiling. Partial gelatinisation during parboiling was sufficient to produce grains with excellent milling quality showing a head rice recovery that ranged from 98% to 100% among the varieties studied.
  
  
  CONCLUSIONS
  Degree of gelatinisation is the most important factor that determines the high head rice recovery. High pasting stability and low setback of flour of parboiled rice indicate some potential food applications.
authors.affiliation: The Faculty of Agricultural Sciences, Sabaragamuwa University of Sri Lanka, P.O. Box 02, Belihuloya, Sri Lanka.
authors.forename: Anil
authors.initials: A
authors.lastname: Gunaratne
authors.forename: Wu
authors.initials: W
authors.lastname: Kao
authors.forename: Jennet
authors.initials: J
authors.lastname: Ratnayaka
authors.forename: Lilia
authors.initials: L
authors.lastname: Collado
authors.forename: Harold
authors.initials: H
authors.lastname: Corke
mesh_terms: D003296:Cooking / Q000379:methods*; D005504:Food Analysis; D006358:Hot Temperature; D012275:Oryza / Q000737:chemistry* / Q000145:classification*; D013213:Starch / Q000737:chemistry*; D014783:Viscosity
chemical_list: D013213:Starch
keywords: functional properties; gelatinisation; parboiling; rice flour