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

Authors: Beaulieu, John; Reed, Shawndrika; OBANDO-ULLOA, JAVIER - Technology Associates; McClung, Anna

Submitted to: Food Science and Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/29/2020
Publication Date: 4/13/2020
Citation: Beaulieu, J.C., Reed, S.S., Obando-Ulloa, J.M., Mcclung, A.M. 2020. Green processing protocol for germinating and wet milling brown rice beverage formulations: Sprouting, milling and gelatinization effects. Food Science and Nutrition. 2020(8):2445-2457. https://doi.org/10.1002/fsn3.1534.
DOI: https://doi.org/10.1002/fsn3.1534

Interpretive Summary: Rice feeds approximately half the world’s population. However, due to milling losses, white rice is a poor source of vitamins and minerals. Brown rice is nutritionally superior yet oils and rancidity can be problematic regarding organoleptics during processing and storage. Sprouting and/or germinating brown rice increases several health-promoting compounds. To avoid rancidity issues, stabilized rice, rice flour, bran and/or pre-processed byproducts were used in most past research and invention. Rice-derived plant-based beverages offer non-soy, lactose-free, hypoallergenic, cholesterol and gluten free food sources. Rice beverages offer options for those with lactose intolerance, gluten sensitivities, health-related issues and desires to cut back on animal products. With plant-based healthier nutrition in consumer’s minds, dairy milk consumption is decreasing, and national and worldwide consumption and production of plant-based beverages are overtaking the beverage industry. Between 2009 and 2015, worldwide sales of non-dairy milk alternatives more than doubled to $21 billion. Herein, we are using green technologies, focusing on brown rice processing regimes with enzymatic treatments, which do not rely upon stabilization, to produce value-added rice beverages. We define “green technologies” for food processing as sustainable, less harmful to the environment, and safe natural chemical processes used to transform raw produce into value-added foods and ingredients, including use of endogenous and food grade enzymes which provide reaction specificity, sensitivity and non-toxicity. Paddy (rough) rice of the variety Rondo was dehulled using a pilot plant dehusker, sorted, cleaned, rinsed, and germinated under various conditions (times and temperatures). Based upon proximate analysis, phytic acid and processing efficiency, we have established a germination process that engages the natural enzymatic hydrolysis of starch and other biochemical changes, which was stopped before major protein, oil and carbohydrate losses occurred. Germinated brown rice (96.7 ± 0.8% germination and coleoptile length 2.24 ± 0.83 mm) was assessed prior to application of a novel method to soften, wet mill, sieve and gelatinize the matrix. The process was termed “free-flowing”, referring to a slurry that is predominately soluble without clumps or gelled materials that pass both 30-mesh and 140-mesh sieves, flowing and pouring smoothly. Developed product color, pH, soluble solids and viscometric behavior was assessed and compared in contrast to commercial rice flours and beverages. Based on rapid visco analyser and sieving results, both proteins and oils apparently remain soluble and were apparently conveyed forward into an enzyme treated solubilized oligosaccharide beverage. We present a novel green processing method for germinating and processing brown rice, leading to a completely and “free-flowing” soluble sprouted brown rice beverage, ready for scale-up and pasteurization.

Technical 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 oils 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 natural enzymatic hydrolysis of starch and other biochemical changes. Based on rapid visco analyser 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.