Milling Properties of Commingled Rice-Cultivar Lots

Abstract

<abstract><title><italic>Abstract.</italic></title> Commingling of rice lots, often of different cultivars, commonly occurs during harvest, storage, and drying operations. Because differences have been observed in the milling properties of rice cultivars, particularly between hybrid and pureline cultivars, there is a need to study the effect of commingling on the milling properties of rice lots, including degree of milling, milling yields, color, and chalkiness. Two long-grain hybrid (H) cultivars (CL XL745 and CL XL729) and two long-grain pureline (P) cultivars (CL 151 and Wells) were used to prepare H/P, H/H, and P/P commingles in various proportions. Milled rice yield (MRY), head rice yield (HRY), surface lipid content (SLC), and head rice color and chalkiness were measured for individual-lot samples as well as for the above-mentioned commingled samples. Kernel dimensions, total lipid content (TLC), chalkiness, and bulk density of brown rice samples of the individual-cultivar lots were also measured. The MRYs, HRYs, and head rice chalkiness of commingled samples trended according to the weighted average of the individual-lot MRYs, HRYs, and head rice chalkiness, respectively. No significant differences were observed in head rice whiteness and yellowness of the commingled samples milled to the same degree of milling (0.4% SLC). In addition, evidence suggested that commingling of cultivar lots with poor HRYs can deleteriously affect HRYs of commingled samples to some extent, and speculative evidence suggested that the individual-lot brown rice TLC, length, width, and bulk density affect the milling dynamics of commingled samples. These findings are intended to help decide if individual-cultivar lots should be commingled, given the brown rice and milling properties of these cultivar lots.