Utilization of Nongkhai Black Jasmine Rice Bran Oils for Development of Functional Drink Emulsion

Abstract

Rice bran is a nutritious by-product from rice milling process. It is usually used as animal feed otherwise rejected as waste that could raise environmental issues. This research aims at utilizing oil extracted from Nongkhai black jasmine rice bran to develop an oil-in-water emulsion drink. Oil was extracted from Nongkhai black jasmine rice bran using hexane as a solvent by Soxhlet extraction method. Nongkhai black jasmine rice bran gave an oil yield of 12.38%. The extracted oil contained total phenolic 120.03 ± 1.26 μg GAE/g oil, flavonoid 46.90 ± 0.69 μg QE/g oil and γ-oryzanol 236.73 ± 7.54 μg/g oil. The antioxidant activity of the oil tested by DPPH, ABTS, and FRAP were 1676.63 ± 76.86, 592.75 ± 46.22, 1.31 ± 0.22 μg Trolox equivalent/g oil, respectively. An oil-in-water emulsion beverage was then developed by dispersing 1% (w/w) of Nongkhai black jasmine rice bran oil with 0.1% (w/w) of Tween80/Span80 (1:1 w/w) as emulsifiers in water. The sweetness of the emulsion beverage was adjusted by adding erythritol mixed with stevia extract sweetener at 0.1, 0.2, 0.3, and 0.4 % (w/v). After pasteurization, all emulsion beverages were subjected to Just-about-right and 9-point hedonic sensory tests using a randomized complete block design. The emulsion containing 0.4 % sweetener had the highest overall liking score of 7.0 ± 1.1, representing moderate liking. The emulsion beverage contained γ-oryzanol 13.3 ± 0.3 μg/mL with the antioxidant activity tested by ABTS of 267.0 ± 37.7 μg Trolox equivalent/mL. In conclusion, Nongkhai black jasmine rice bran is a source of bioactive lipids that can be utilized as an ingredient in a plant-based functional drink emulsion.