2017 ASHS Annual Conference

Rice milk beverages offer lactose-free, hypoallergenic, cholesterol and gluten free value-added food sources which, with natural fortifications, may offer well balanced nutrition. With healthier nutrition in consumer’s minds, national and worldwide consumption/production of plant-based milk beverages are increasing. Much past research and invention was based on enzymatic conversion processes for starch that were uncomplicated because the utilized stabilized rice or rice flour had minimal fat, fiber, protein and contaminants. The ultimate objective is using green technologies focusing on brown and colored rice with berry-based infusions and enzymatic treatments (not relying upon stabilization) to produce rice milk products. Herein, we focus on preliminary details regarding wet-milling and pre-germinating brown rice prior to gelatinization and enzyme treatments. ‘Rondo’ paddy rice was freshly hulled using a pilot plant dehusker, manually sorted in mesh sieves along with culling out rough rice kernels and rice stinkbug/smutty grains. Then 400g brown rice was pre-rinsed, placed into 1L mason sprouting jars with screen lids, for 30min soaking treatments at 35°C in water and peracetic acid (30 and 300ppm). Rice was soaked 24 hr in water at 35°C then was inverted for 24 hr germination; both with 4 hr periodic rinses. Samples were softened at 65-70°C in a hot water bath until wet-milled kernels passed through a 30-mesh sieve prior to gelatinization at 75-90 °C. Measurements included proximate analysis, pH, phytase, arsenic content, germination % and coleoptile lengths, total phenolics, microbial, starch/sugar and °Brix. Initial ‘Rondo’ pH was ~7.00-7.16 which dropped after germination to 5.20±0.05, with germination rate of 97.0-99.0±1.0%. Proximate brown rice analysis for crude protein (%), fat (%), fiber (%), ash (g/100g) and moisture content (%) was: 7.23±0.10, 4.16±0.13, 1.70±0.10, 1.40±0.03 and 9.88±0.09, respectively. Protein, fat and ash decreased in all treatments after germination, and coleoptile lengths (2.30±0.89mm) decreased slightly in peracetic acid (~2.09±0.71mm). Phytic acid (0.78%) decreased markedly after germination, and with increasing treatment acidity, as there was 0.25±0.01, 0.21±0.01 and 0.17±0.00% in control, 30 and 300ppm peracetic acid, respectively. Total phenolics increased from initial brown rice (7.21±0.48µl/ml); however, the highest acidity was detrimental whereby there was 7.52±0.44, 7.61±0.36 and 6.93±0.73µl/ml in germinated control, 30 and 300 ppm peracetic acid respectively. The initial total arsenic was 0.52±0.01mg/kg, comprised by inorganic (0.22±0.01) and organic (0.25±0.02) species. Initial liquefaction enzyme treatments for starch/sugar conversions and analyses are in progress.