Green processing protocol for germinating and wet milling brown rice for beverage formulations: Sprouting, milling and gelatinization effects

Abstract

Rice-derived beverages offer a non-soy, lactose-free, cholesterol and gluten-free food source, which may offer well-balanced nutrition. Brown rice is nutritionally superior to white rice but oil oxidation and rancidity can be problematic regarding organoleptics during processing and storage. Using green technologies, which do not rely upon stabilization, brown rice was sprouted and processed with enzymes to produce preliminary value-added rice beverages. Paddy (rough) Rondo rice was dehulled using a pilot plant dehusker, sorted and cleaned into brown rice (BRR), rinsed, and germinated under various conditions (times and temperatures). Germinated brown rice (GBR) was then assessed (96.7 ± 0.8% germination and coleoptile length 2.24 ± 0.83 mm) prior to developing a method to soften, wet mill, sieve and gelatinize the matrix. Moderate macronutrient catabolism based on proximate analysis (e.g., 27.0%, 30.9% and 28.9% protein, oil and carbohydrate loss, respectively) and significantly decreased phytic acid (71.6%) from BRR → GBR along with processing efficiency were used to establish a germination and processing protocol engaging the natural enzymatic hydrolysis of starch and other biochemical changes. Based on rapid visco analyzer pasting properties in heated BRR, GBR sieving results and observations of stored crude beverages, proteins and oils apparently remained soluble and were conveyed forward into an the enzyme-treated solubilized oligosaccharide matrix, which could be a natural emulsion. A method for germinating and processing brown rice, leading to a completely green process and "free-flowing" soluble matrix to deliver preliminary sprouted brown rice beverages is presented.