Study On Antioxidant Activity Of Rosemary Extract And Its Usage In Salt-baked Chicken Wings

Antioxidant properties and application of carnosic acid（CA）, carnosol（CS） and rosemary acid（RA） were studied in this paper. Vitro antioxidant capacity of CA, CS and RA were determined by four vitro oxidation tests. Oil peroxide value（PV） was as an indicator to evaluate the antioxidant effect of CA, CS and RA to chicken-oil and peanut-oil system. CA, CS and RA were added to salt-baked chicken wings by penetration and immersion, and the antioxidant effect was analyzed by thiobarbituric acid reactive substances（TBARS）. The summary of research results are as follows:（1） In DPPH radical scavenging assay, IC₅₀ of RA, CA, and CS were 14.23 mg/mL, 16.54 mg/m L, and 41.89 mg/m L. RA had the strongest scavenging capacity of DPPH, followed by TBHQ, CA, BHA and CS. The higher the sample concentration was, the greater clearance rate the antioxidants had for ABTS radical scavenging capacity. RA had the strongest scavenging capacity of ABTS. TBHQ and BHA had the second strongest scavenging ABTS capacity, and followed by CA and CS. Scavenging superoxide anion test was not suitable to evaluate RA and CS. CA, BHA and TBHQ had the same behavior when the sample concentration within 100 mg/mL, while sample concentration increased, rank of scavenging O2?- capacity were: TBHQ> BHA> CA. In Prussian Blue reducing power test, the higher the concentration of antioxidants were, the stronger the capacity to deoxidize potassium hexacyanoferrate（III） to potassium hexacyanoferrate（II） was. Order of reduction activity was: RA> BHA> CA> TBHQ> CS.（2） Chicken-oil and peanut-oil were rich in unsaturated fatty acids, which were easy to be oxidized. Chicken-oil without any antioxidants could be stored at room temperature（20℃） for 87 days, and peanut-oil 81.7 days. CA contributed significant antioxidant effect to chicken-oil. Chicken-oil with 150 ppm CA could be stored at 20℃ for about 6 months, and when CA addition amount was cut down to 10 ppm, shelf-life of chicken-oil could be extended for 45.7 days. CA did the excellent antioxidant effect to peanut-oil, and peanut-oil with a very low addition amount（10 ppm） had significant inhibition for oxidation which predicted-shelf-life was153.3 days. When CA addition amount ranged from 30 ppm to 150 ppm, the dose-effect relationship was not obvious, but all treated groups could be stored for more than 200 days. Effect of CS to chicken-oil is not obvious. 10⁶0 ppm treated groups shared the predicted-shelf-life for about 110 days, 30 days longer than the control group, while 100 ppm and 150 ppm treated groups could be stored for 136 days and 139.3 days respectively. In peanut-oil system, antioxidant effect of CS is not as good as CA. Addition of 10 ppm CS could extend the shelf-life for about 10 days. PV-t curve of 60¹00 ppm treated groups were messy in the first 200 hours, but after dose-effect relationship was visible, and predicted-shelf-life ranged from 146.7 days to 226.7 days. RA had poor oil-solubility, but there was still a weak protective effect of peanut-oil oxidation. However, increasing the amount of RA did little help to its antioxidant effect. Emulsification could improve oil-solubility of RA, and enhance its antioxidant effect for chicken-oil and peanut-oil, but dose-effect relationship was not obvious. When added with the same concentration（100 ppm） in peanut-oil or chicken-oil system, order according to antioxidant activity was as follows: TBHQ> CA> CS> BHA> RA, and for the same antioxidant it showed more active antioxidant capacity in peanut-oil than in chicken-oil.（3） CA, CS and RA were added to salt-baked chicken wings when or after marinating. Regardless of antioxidant added way, there came to same conclusion: the greater the amount of antioxidants were or the greater the soaking liquid concentration was, the lower TBARS value the corresponding chicken wings got, and the better inhibition of lipid oxidation the antioxidants showed. For the same added way, RA showed the best antioxidant effect, followed by CA and CS. Penetration rate of CA, CS and RA in brine were 7.29%, 11.61%, and 24.89%. Chicken wings could be wrapped around 0.0143 m L soaking liquid per gram chicken wings when soaked for about 15 seconds. With different monomers of rosemary extracts, antioxidant added after marinating showed more active antioxidant capacity than added when marinating if residues in final chicken wings product were in the same level.