Cereal Chem 52:182 - 187.  |  VIEW ARTICLE
Chemical, Physical, and Nutritional Properties of High-Protein Flours and Residual Kernel from the Overmilling of Uncoated Milled Rice. IV. Thiamine, Riboflavin, Niacin, and Pyridoxine.

B. M. Kennedy, M. Schelstraete, and K. Tamai. Copyright 1975 by the American Association of Cereal Chemists, Inc. 

Average vitamin contents with standard deviations for six varieties of whole kernel rice were, per 100 g.; thiamine, 0.13 +/- 0.04 mg.; riboflavin, 40 +/- 3 gamma; pyridoxine, 136 +/- 21 gamma; niacin (10 lots of rice), 1.5 +/- 0.6 mg. For two lots of parboiled rice, values were 0.15 +/- 0.03 mg., 44 +/- 6 gamma, and 3.2 +/- 0.1 mg. for thiamine, riboflavin, and niacin, respectively. Contents of first-pass flours obtained by abrasive milling were greater than those in the original kernel; five times as great for riboflavin, eight for thiamine and pyridoxine, and 14 for niacin. For the two parboiled rices, values were four times as great for riboflavin and thiamine and eight for niacin. Concentrations of the vitamins were greatest in the periphery of the kernel and decreased toward the center, except for niacin in the parboiled rices in which case the highest concentrations were found in the second-pass flours, 17 times as much as in the whole kernels. Of the vitamins studied, riboflavin was the most evenly distributed throughout the kernel, with little difference between the parboiled and untreated rices, whereas niacin was the least evenly distributed.Thiamine was more evenly distributed throughout the parboiled rices than it was in the untreated rices. Flours from the periphery of the kernel, comprising 6 to 7% of the total endosperm, contained from one-fourth to one-half of the vitamins present in the whole endosperm.