Formulation of O/W Emulsions containing Rice Bran Oil from Various production methods and Evaluation of free radical Scavenging activity

Abstract

The purposes of this study were to report the production methods of rice bran oil (RBO) that influence free radical scavenging activity, amount of γ-oryzanol and vitamin E. Also, to study the formulation of o/w emulsions from different RBO produced from 5 methods which are called as solvent extraction RBO (SE-RBO), bleached-solvent RBO (BSE-RBO), cold-pressed RBO (CP-RBO), bleached cold-pressed RBO (BCP-RBO) and refined RBO (RE-RBO), The free radical scavenging activity (IC50) of these RBOs were ranked from the highest to lowest, as follows: SE-RBO (IC50 = 2.23±0.22 mg/mL), CP-RBO (IC50 = 2.29±0.04 mg/mL), BSE-RBO (IC50 = 2.46±0.21 mg/mL), BCP-RBO (IC50 = 2.59±0.14 mg/mL) and RE-RBO (IC50 = 4.53±0.12 mg/mL). There were not significantly different between SE-RBO, BSE-RBO, CP-RBO, BCP-RBO (P>0.05) except RE-RBO which was significantly lower (P<0.05) in term of DPPH scavenging activity. The γ-oryzanol content were ranked from the highest to the lowest as follow: SE-RBO (14614.37±70.69 ppm), CP-RBO (13917.92±115.44 ppm), BSE-RBO (13199.41±120.57 ppm), BCP-RBO (12855.82±77.02 ppm), and RE-RBO (3487.03±100.02 ppm). The γ-oryzanol content for the different production methods were significantly different (P<0.05). Moreover, the amount of vitamin E for the processing of RBO showed that CP-RBO (527.83±0.26 ppm) had the highest vitamin E content follow by SE-RBO (442.83±0.23 ppm), BCP-RBO (357.57±0.38 ppm), BSE-RBO (350.94±0.38 ppm) and the RE-RBO (170.56±0.31 ppm) had the lowest vitamin E content. The estimated oxidative stability can be ranked from the lowest to highest as follows: BSE-RBO (0.48±0.97 h), BCP-RBO (2.86±0.16 h), RE-RBO (3.69±0.05 h), CP-RBO (9.39±1.07 h) and SE-RBO (9.93±0.21 h). In addition, O/W emulsions containing different RBO were formulated. All various RBO emulsions were approximately in acceptable range of skin pH (5-6). RE-RBO gave the most ‘satisfy’ with its color and spreadability. CP-RBO gave the most ‘satisfy’ with skin feel and BCP-RBO gave the most ‘satisfy’ with odor and smooth cream mass. On the other hand, SE-RBO gave the least score in all categories. Moreover, all formulations showed good physical stability after 6 cycles of temperature cycling.