Study On Extraction Of Rosemary Antioxidant And Its Application In Oil

In recent years, studies on the active function of rosemary extract have gradually increased, most of which are mainly focused on the antioxidant function. At present,rosemary extract has been included in the use of Chinese food additives standards (GB/2760)as a new type of natural antioxidant. However the research on rosemary in China started late,so the research and application of rosemary extract is not comprehensive enough. To realize the depth development and utilization of rosemary antioxidant, in this paper, we used rosemary as raw material and determined the best extraction process according to the effect of different extraction methods on the antioxidant activity of rosemary extract. Then the antioxidant effect of rosemary extract in vegetable oil and animal oil were evaluated. The main research content is as follows:The best reflux extraction process was determined through single factor and response surface optimization experiments, the result was: 80 % ethanol, exctraction temperature 80 ?, exctraction time 1 h, ratio of solutions to material 10:1,2 times. In this condition, the total phenolic content of rosemary extract was 33.85 mg/g.The best ultrasonic assisted extraction process was determined through single factor and response surface optimization experiments, the result was: exctraction temperature 50 ?,exctraction time 40 min, ratio of solutions to material 10:1, 80 % ethanol, 2 times. In this condition, the total phenolic content of rosemary extract was 36.58 mg/g.The rosemary extracts were obtained by different extraction methods under the optimal conditions, then the two extraction methods were compared with the yield, total phenolic content, the content of camosic acid, carnosol, rosmarinic acid and antioxidant activity of the rosemary extract. The results showed that the extraction yield and total phenolic content of rosemary extract which was obtained by refluxing extraction were 20 % and 33.85 mg/g, the content of carnosic acid, carnosol and rosmarinic acid were 3.6 %, 6.6 % and 3.4 %. The extraction yield and total phenolic content of rosemary extract which was obtained by ultrasonic assisted extraction were 20.1 % and 36.58 mg/g, the content of carnosic acid,carnosol and rosmarinic acid were 7.8 %, 10 % and 3.6 %.Then the palm oil and the lard were chosen as the representative of vegetable oil and animal oil. The accelerated oxidation experiments were conducted under the high temperature and low temperature conditions. In the experiment, we compared the antioxidant effect of rosemary antioxidant with BHA, TBHQ and tea polyphenols. According to the maximum use of the antioxidants in the national standard, we set different concentration gradients and determined the best adding amount, then oil samples were carried out to accelerate the oxidation experiment, results were obtained by measuring the antioxidant indexes of oil samples. In high temperature frying condition, optimum amounts of BHA,TBHQ, rosemary antioxidant and tea polyphenols in palm oil were 0.012 g/100g, 0.012 g/100g, 0.012 g/100g and 0.020 g/100g respectively. After 25 h of frying experiment,peroxide value, acid value, iodine value and other antioxidant index were determined, results showed that the effect of rosemary antioxidant was significantly better than other antioxidants.In low temperature storage condition, optimum amounts of BHA, TBHQ, rosemary antioxidant and tea polyphenols in palm oil were 0.020 g/100g, 0.016 g/100g, 0.070 g/100g and 0.040 g/100g respectively. After 24 d of storage experiment, peroxide value, acid value,iodine value and other antioxidant index were determined, results showed that rosemary antioxidant and tea polyphenols have better antioxidant effect, rosemary antioxidant was better than tea polyphenols. In high temperature heating condition, optimum amounts of BHA, TBHQ, rosemary antioxidant and tea polyphenols in lard were 0.020 g/100g, 0.020 g/100g, 0.018 g/100g and 0.032 g/100g respectively. After 25 h of heating experiment,peroxide value, acid value, iodine value and other antioxidant index were determined, results showed that rosemary antioxidant and TBHQ have better antioxidant effect, TBHQ was better than rosemary antioxidant. In low temperature storage condition, optimum amounts of BHA, TBHQ, rosemary antioxidant and tea polyphenols in lard were 0.020 g/100g, 0.012 g/100g, 0.024 g/100g and 0.040 g/100g respectively. After 24 d of storage experiment,peroxide value, acid value, iodine value and other antioxidant index were determined, results showed that rosemary antioxidant and TBHQ have better antioxidant effect, TBHQ was better than rosemary antioxidant.