Effects of Drying Methods on the Nutritional and Physical Quality of Pre-Germinated Rice

摘要

Pre-germinated rough rice (pre-GRR) and pre-germinated brown rice (pre-GBR) were dried to below 14% wet basis (w.b.) by various drying schemes involving three dryers: hot-air oven (HAO), fluidized-bed dryer (FBD), and solar dryer (SD). The aim of thisresearch was to investigate the effects of drying methods on the y-aminobutyric acid (GABA) content, antioxidant activity, fissuring, and color of GABA rice produced from pre-GRR and pre-GBR in order to maximize the quality ofGABArice. The HAO was operated at 50° C, while the drying temperatures for FBD were 80° C, 100°C, 120°C, and!40°C. The GABA contents of GABA rice produced from pre-GRR and pre-GBR before drying were 25.4 and 22.1 mg per 100 g dry mass of sample, respectively. The antioxidantactivities of GABA rice produced from pre-GRR and pre-GBR were 32.89 and 26.11 mg BHAE (t-butylated hydroxyanisole equivalent) per 100 g sample dry mass, respectively. Both GABA content and antioxidant activity were diminished after drying, especially inthe case of single-stage drying at 50 °C. The multi-stage drying with intermittent tempering steps significantly reduced the fissured kernels. After drying, the lightness of samples was lowered whereas the redness and yellowness were increased. The results of this study recommend GABA rice to be produced from pre-GRR rather than pre-GBR because of its increased GABA content and antioxidant activity, lower tendency to fissuring, and similarity of color to typical brown rice.