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ARS Home » Southeast Area » Stuttgart, Arkansas » Dale Bumpers National Rice Research Center » Research » Publications at this Location » Publication #191128
Title: SMALL-SCALE INDUCTION OF POSTHARVEST YELLOWING OF RICE ENDOSPERM

Author
item Miller, Helen
item KAY, MARK - UA RREC
item LEE, FLEET - UA RREC

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2006
Publication Date: 2/15/2006
Citation: Miller, H.B., Kay, M.G., Lee, F.N. 2006. Small-scale induction of postharvest yellowing of rice endosperm [abstract]. Rice Technical Working Group Meeting Proceedings, February 29-March 1, 2006, Houston, Texas. 2006 CDROM.

Interpretive Summary:

Technical Abstract: Rice endosperm often develop a yellow discoloration during commercial storage in conditions of high temperature and moisture, thereby reducing the value of the grain. This postharvest yellowing (PHY) appears to be coincidental with fungal presence. In order to study the yellowing process in a controlled manner, we developed a technique to induce PHY on a small, laboratory scale. Milled rice kernels were rinsed with water and incubated in clear test tubes or microfuge tubes at 65-80oC. This allowed direct observation of the color change and measurement using a colorimeter. Every rice cultivar tested, which included long and medium grain japonicas and indicas, showed some level of PHY. Yellowing increased with temperature yielding a maximum color change at 79oC. Most of the color change occurred within one day. The moisture parameters required for yellowing to occur were measured. Using sterilization and culture techniques, we found no indications of direct fungal involvement in the yellowing process.