Abstract:
The purposes of this study were to select the type and concentration of antioxidant with the highest antioxidant activity in rice bran oil (RBO) and to evaluate the lip conditioning properties of the selected RBO lipsticks in healthy volunteers. The antioxidant efficacy study between tertiary butylhydroquinone (TBHQ) and butylated hydroxyanisole (BHA) under accelerated conditions by 743 Rancimat at 120 degrees celsius were studied. A series of concentrations for each antioxidant was between 0.01-0.10% by weight. The stability of rice bran oil was increased when using higher concentration of antioxidants. TBHQ and BHA have comparable antioxidant efficacy on rice bran oil at levels less than 0.04%. At levels greater than 0.04%. TBHQ is far more effective than BHA significantly (P<0.05). TBHQ at 0.10% by weight was used to stabilize RBO in lipstick preparation. Lipsticks were formulated using oil, fat, and wax. The optimum oil:fat:wax was 76:10:14 by weight. The SPF values of lipsticks measuring by SPF-290s analyzer were increased when using higher concentrations of rice bran oil. Moreover, rice bran oil lipstick showed high efficacy in improving skin-feel, high gloss, good glide and less tackiness. Forty-five healthy female panelists were participated in the study of lip conditioning properties of lipsticks. Lip capacitance, melanin value and hemoglobin value had been measured weekly for 6 weeks. There is no statistical difference among three treatments in all properties. All treatments could increase lip capacitance and hemoglobin value while decrease melanin value significantly with time goes by. Lipsticks containing RBO and lipsticks containing RBO plus [upsilon]-oryzanol induced modest lip conditioning effect compared to control treatment. But lipsticks containing RBO and lipsticks containing RBO plus [upsilon]-oryzanol have comparable efficacy in all properties. The sensory evaluation perceived by panelists informed that lipstick containing RBO plus [upsilon]-oryzanol was evaluated as the most 'satisfy' with its high slipperiness, high gloss, increase moisturizing effect, increase lip redness, decrease lip darkness, and least tackiness.