Green processing sprouted brown rice for beverage formulations: Lipid characterization

Authors: Beaulieu, John; Moreau, Robert; Powell, Michael; OBANDO, ULLOA - Institute Of Technology

Submitted to: Institute of Food Technology
Publication Type: Abstract Only
Publication Acceptance Date: 1/31/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: Milled polished white rice is nutritionally inferior to brown rice yet, brown rice and bran oils are subject to rancidity during processing and storage. Germinating brown rice is known to generally increase several health-promoting compounds. In response to increasing consumption of plant-based beverages, we sprouted brown rice using green technologies and enzymes for making value-added rice beverages. “Green technologies” for beverage processing are defined herein as sustainable, less harmful to the environment, and safe natural physical processes used to transform raw product into value-added foods and ingredients, including use of endogenous and food grade enzymes which, provide reaction specificity, sensitivity and non-toxicity. Ultimately, beverages may contain 100% truly natural, unstabilized, endogenous ingredients with little to no additives or emulsifiers. Paddy rice was dehulled, germinated and brown rice beverages were produced and compared against the non-germinated brown and white brewers rice beverages. Samples were subjected to accelerated solvent extraction and nonpolar lipid analysis for total oil (lipids), palmitic, stearic, linoleic and linolenic acids, unknown free fatty acids, free sterols, phytosterol esters (nonpolar lipids), diacylglycerols (DAG), triacylglycerols (TAG) and oryzanol. Starting materials contained roughly 0.77, 2.78, and 3.95 sprouted ' into 2.46 wt% (dry weight basis), total lipids in white rice, brown rice, brown rice used for sprouting and germinated brown rice, respectively. Total free fatty acids recovered in white, brown and germinated brown rice were 523.06, 53.15 and 47.79 mg/100g, respectively. Germinated brown rice contained significantly lower levels (97.29 mg/100 g) of phytoesterol esters compared to brown rice (138.50 mg/100 g). Sprouting conditions used herein resulted in a significant 2-fold reduction in the '-oryzanol. Two sieving steps resulted in the highest concentration (loss) of many oils. Germinated brown rice beverages contained significantly higher concentrations of total oil, diacylglycerols, triacylglycerols, free sterols, phytosterol esters and total oil-related compounds recovered than both non-germinated brown and white rice beverages.

Technical Abstract: Past rice technology and processing revolved around stabilization and oil removal, which is becoming undesirable to both industry and consumers. Brown rice is nutritionally superior to white rice but oils and rancidity can be problematic. Germinating brown rice is known to generally increase several health-promoting compounds. The plant-based drink market is expected to surpass $34 billion by 2024. We therefore began using green technologies, without stabilization, on sprouted brown rice along with saccharification enzymes for novel value-added rice beverages. The goal is to convey and/or augment health-beneficial compounds from brown rice into a completely natural (no additives or fortification) improved beverage. Paddy rice was dehulled, graded and soaked/germinated at 35 °C for 48 hours, pre-softened thermally at 70 °C, wet milled then gelatinized to facilitate saccharification with food-grade enzymes. Beverages were produced from germinated brown rice (GBR), and non-germinated brewers white rice (WR) and brown Rondo rice (BRR). A green processing method was optimized for GBR, which was compared against the BRR and WR preliminary beverages. Freeze dried samples were subjected to accelerated solvent extraction and nonpolar lipid analysis for total oil (lipids), palmitic, stearic, linoleic and linolenic acids, unknown free fatty acids, free sterols, phytosterol esters (nonpolar lipids), diacylglycerols (DAG), triacylglycerols (TAG) and oryzanol. A one-way analysis of variance was used (JMP 13 PRO for Windows). Starting materials contained roughly 0.77 (WR), 2.78 (BRR), and 3.95 (BRR for sprouting) and 2.46 (GBR) wt% (dwb), total lipids respectively. Total FFAs recovered in WR, BRR and GBR were 523.06, 53.15 and 47.79 mg/100g, respectively. The BRR ' GBR and BRR controls contained the significantly highest level of TAGs in all samples analyzed, with 3163.5, 1919.2 and 2356.2 mg/100g, respectively. GBR contained significantly lower levels (97.29 mg/100 g) of phytoesterol esters compared to BRR (138.50 mg/100 g). Sprouting conditions used herein resulted in a significant 2-fold reduction in the '-oryzanol. Two sieving steps resulted in the highest concentration (loss) of many oils. GBR beverages contained significantly higher concentrations of total oil, diacylglycerols, triacylglycerols, free sterols, phytosterol esters and total oil-related compounds recovered than both non-germinated brown and white rice beverages.