Lipid and protein comparison in beverages from white rice, non-sprouted brown and sprouted brown rice

Authors: Beaulieu, John; Moreau, Robert; Hojilla-Evangelista, Milagros - Mila; OBANDO-ULLOA, JAVIER - Institute Of Technology

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Brown rice is nutritionally superior to white rice yet oils and rancidity can be problematic regarding sensory attributes during processing and storage. The functional beverages marketplace is thriving and plant-based beverages have become an integral component; expected globally to surpass $34 billion by 2024. Germinating or sprouting brown rice is known to generally increase several health-beneficial compounds. Subsequently, we germinated brown rice (GBR) using green technologies and saccharification food-grade enzymes for making value-added rice beverages. ‘Rondo’ paddy rice was de-hulled, graded, rinsed, germinated at 35 °C for 48 h and beverages produced, as previously published. These were compared against beverages produced from the non-germinated ‘Rondo’ brown (BR) and brewers white rice (WR). No additives, salt, oils or fortification were used in this green processing. Freeze dried samples were subjected to accelerated solvent extraction and nonpolar lipid analysis for total oil (lipids), palmitic, stearic, linoleic and linolenic acids, free sterols, phytosterol esters, diacylglycerols, triacylglycerols and oryzanol. Native gel electrophoresis, SDS-PAGE, protein determination and solubility tests were performed to assess differences between the three beverage types, with comparison to commercial rice beverages. A one-way analysis of variance was used (JMP 13 PRO for Windows). Germinated brown rice beverages contained higher protein levels than non-germinated beverages, and all three beverages had markedly higher protein concentrations (~5%) than tested commercial rice beverages (generally = 1%). The protein was roughly 10% soluble. A unique 6.5 kDa polypeptide band was attributed to possible increased solubility in both sprouted and non-sprouted brown rice beverages. Potentially unique polypeptides were also recovered at 58 and 66 kDa. GBR beverages contained significantly higher total lipids (0.62%, dwb) than both the BR and WR beverages (0.23 and 0.14%, respectively). Phytosterol esters (containing nonpolar lipids and wax esters) were recovered between 20.4 - 138.5 mg/100g in BRR and GBR processing stages, whereas Decloedt et al., (2018) reported 4.3 mg/100 ml in a rice beverage. The GBR beverage contained significantly greater concentrations of oryzanols (5.84 mg/100g) than non-germinated BR and WR beverages (1.15 and 0.36 mg/100g, respectively). The GBR beverage contained significantly greater concentrations of total free sterols (8.74 mg/100g) than non-germinated BR and WR beverages (3.43 and 2.03 mg/100g, respectively) and double the level reported in a rice beverage (4.29 mg/100g) by Decloedt et al., (2018). Sieving fractions resulted in significant protein and lipid losses. Consequently, emulsification has been developed for pilot plant scale-up, including flash pasteurization for consumer-ready products.