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.
