Losses in Qualities and Aromatic Contents of Hom Mali Rice in Production Chain

Abstract

As a result of a feedback reflecting from the entrepreneurs and consumers about a reduction in the aroma of Thai Hom Mali rice, this study, thus, monitored and evaluated the losses in quality and aroma throughout the production chain of Thai Hom Mali rice via 25 production routes from Ubon Ratchathani, Roi Et, Amnat Charoen, Chiang Rai and Phayao. The experiments were conducted during 2017-2018 with collecting the rice samples in all production step begining from harvesting, drying process operated by mills, transforming with milling and polishing processes, processing process, and packaging. The physical and chemical qualities of rice grains were analyzed. The results showed that the amount of an aromatic 2AP dividing by types of rice including the good quality Hom Mali, the general Hom Mali, the organic Hom Mali for export, and the general organic jasmine rice ranged from 3.34-4.76, 2.54-5.05, 2.51-5.27 and 3.44-4.18 ppm, respectively. The levels of physical and chemical qualities of RD15 and KDML 105 samples in all routes of production chain were in the standard criteria of Thai Hom Mali rice which consisted as follows: the grain length is not less than 7 mm, the ratio of length to width are not less than 3.2:1, the amylose contents range from 13.018.0%, the alkali test values are between 6 to 7. Whilst, the the aroma of the good quality Hom Mali, the general Hom Mali, the organic Hom Mali for export, and the general organic jasmine rice decreased by average of 37.0, 55.8, 39.4 and 42.5%, respectively. Decreases in 2AP contents of rice grains were found in all steps of production chain with high reduction after drying process (17-28%), whereas a decrease in 2AP contents of rice grains from the milling process ranged from 15-24%. Moreover, pile of the rice grains with different rice qualities, temperature for moisture reduction and transforming process also contribute for the reduction in aroma of rice. Therefore, reduction the moisture content in the grains of organic rice by using sun drying method and milling as the requirements of the cutomers which were commonly used by the farmers minimized the loss of aroma in rice because of fewer steps than those of the process operated by mills.