The Effect of Different Milling Times on Grain Iron Content and Grain Physical Parameters Associated with Milling of Eight Genotypes of Rice (Oryza sativa L.)
The effect of different milling times on its iron content were determined using eight genotypes of rice (Oryza sativa L.): Azucena, IR74796-3B-34-1-1, IR75399-2B-4-2-1, IR68144-23-2-2-3, PSBRc 28, IR71684-36-3-3-2, IR76528-18-2-2-2-2, and IR64. The eight genotypes of rice were grown in the field and, after harvesting, the samples were prepared for milling. The milling times used were as follows: 0, 10, 20, 30, 40, 50, 60, and 70 sec. Iron content and physical parameters like total milled rice, percent milling ratio, weight of head rice, percent milling recovery, whiteness, transparency, and milling degree were obtained. The experiment was laid out in a two- factorial strip plot design. Analysis of variance (ANOVA) showed that the effects of variety, milling time, and interactions of both were highly significant. As milling time increased, iron content in grains decreased along with total milled rice and head rice. IR71684-36-3-3-2, IR68144-2B-2-2-3, and IR76528-18-2-2-2-2 had the highest iron content for all milling times. Grain whiteness, transparency, and milling degree increased with milling time. Correlation analysis showed that whiteness, transparency, and milling degree were negatively correlated with grain iron content. Genetic variability observed in the genotypes suggest that combining the desirable grain characters of improved varieties like IR64 with high iron content in grains is attainable.
REFERENCES
BONIFACIO EP. 1989. The effect of milling operations on grain quality and price in selected Philippine rice mills. [M.S. Thesis]. College, Laguna: University of the Philippines Los Baños. 140p. (available at UPLB library)
CHANAKAN P, DELL B, THOMSON P, RERKASEM B. 2003. Easy and rapid detection of iron in rice grain. Science Asia: 203-207.
[DOH] Department of Health. 1998. Food Fortification Project Strategic Plan 2000-2004. Retrieved 26 February 2005 from the world wide web: http://doh.gov.ph/food.FF2.htm.
[FAO] Food and Agricultural Organization (FAO). 1998. Nutrition Country Profiles. Retrieved 26 February 2005 from the world wide web: http://fao.org/es/ESN/nutrition/phi-e.stm.
[FNRI] Food and Nutrition Research Institute. 1998. Retrived 27 October 2004 from the world wide web: http://www.tulane.edu/~internut/Countries/Philippines/philippinesiron.html.
GREGORIO GB. 2002. GM Technology: The Answer to Poor Nutrition?. http://www/scidev.net/dossiers/ gmcrops/gmpolicy gregorio.html.
GREGORIO GB, SENADHIRA D, HTUT T, GRAHAM RD. 2000. Breeding for trace mineral density in rice. Food Nutrition Bulletin 21: 382-386.
HYNES E. 2003. Rice. Microsoft Encarta Reference Library. CD- ROM.
[IRRI] International Rice Research Institute. 1992. IRRISTAT user’s manual, version 92-1. IRRISTAT Development Team. Program Management Services and Biometrics. IRRI, Los Baños, Laguna: International Rice Research Institute. 121p.
JENNINGS PR, COFFMAN WR, KAUFMAN HE. 1979. Rice Improvement. Los Baños, Laguna: International Rice Research Institute 105p.
JULIANO BO. 1985. Rice, Chemistry, and Technology. USA: American Association of Cereal Chemists, Inc. 774p.
JULIANO BO, VILLAREAL CP. 1993. Grain quality evaluation of world rices. Manila, Philippines: International Rice Research Institute. 205p.
KATO S, ISHIKAWA J. 1921. On the inheritance of the pigment of red rice. Jpn J Genet 1: 1-7.
MADAMBA PS. 1983. Effects of grain moisture content on milling recovery, power consumption, and grain temperature. [MS Thesis]. College, Los Baños: University of the Philippines. 85p. (available at UPLB Library)
MANALABE R. 1987. Design and practices of rice milling. Paper presented Regional workshop on design of drying and milling equipment. RNAM/ UPLB.
MERCADO JL. 2004. Rice- for- classes swap. Philippine Daily Inquirer. October 19. A10p.
PARAS AS. 1976. Rice milling principles and systems. Los Baños, Laguna: University of the Philippines, Institute of Agricultural Engineering and Technology.
RUITEN HTL VAN. 1979. A technical assessment of rice milling in the Asean region. Grains Journal N.G.A. 5: 2.
SWEENEY MT, THOMSON MJ, PFEIL BE, McCOUCH S. 2006. Caught red-handed: Rc encodes a basic helix-loop-helix protein encoding red pericarp in rice. The Plant Cell 18: 283-294.
