Analysis of Betaine and Choline Contents of Aleurone, Bran, and Flour Fractions of Wheat (Triticum aestivum L.) Using 1H Nuclear Magnetic Resonance (NMR) Spectroscopy

In conventional milling, the aleurone layer is combined with the bran fraction. Studies indicate that the bran fraction of wheat contains the majority of the phytonutrients betaine and choline, with relatively minor concentrations in the refined flour. This present study suggests that the wheat aleurone layer (Triticum aestivum L. cv. Tiger) contains the greatest concentration of both betaine and choline (1553.44 and 209.80 mg/100 g of sample, respectively). The bran fraction contained 866.94 and 101.95 mg/100 g of sample of betaine and choline, respectively, while the flour fraction contained 23.30 mg/100 g of sample (betaine) and 28.0 mg/100 g of sample (choline). The betaine content for <br/>the bran was lower, and the choline content was higher compared to previous studies, although it is known that there is large variation in betaine and choline contents between wheat cultivars. The ratio of betaine/choline in the aleurone fraction was approximately 7:1; in the bran, the ratio was approximately 8:1; and in the flour fraction, the ratio was approximately 1:1. The study further <br/>emphasizes the superior phytonutrient composition of the aleurone layer. <br/>INTRODUCTION <br/>Wheat is a valuable source of betaine, choline (1, 2), B <br/>vitamins, vitamin E, and a number of minerals, including iron, <br/>zinc, magnesium, and phosphorus (3). Epidemiological studies <br/>indicate that whole-grain consumption is protective against <br/>several chronic diseases (4-12). It has not been fully elucidated <br/>how whole-grain cereals or specific fractions (13) exert their <br/>protective effect, but it is thought to be due to their content of <br/>several nutrients associated with the reduced risk of disease. <br/>Conventionally, whole grain is separated during milling into <br/>bran, germ, and flour (14). The nutrient composition of these <br/>fractions differ markedly; refined wheat flour contains approximately <br/>50% less vitamins and minerals than whole-grain <br/>flour (