Antioxidant Activity Of Chinese Medicinal Herbs In Edible Oils

Edible oils are prone to be oxidated during the preservation and supplementary, antioxidants can slow down the oxidation process. The synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) have antioxidant activities. However, the synthetic antioxidants have the problem with their biosafety. Therefore, the development of effective and safe natural antioxidants becomes one of the main topics in the field of food chemistry. There are many Chinese medicinal herbs available in China and it has been verified that many herbs are full of antioxidative components. In the present study, the antioxidant activities of 33 Chinese medicinal herbs were evaluated, the herb powders with higher antioxidant activities were added into the edible oils for determination of their antioxidant activities. The studies on the antioxidant activity of Chinese medicinal herbs in edible oils will provide relating knowledge for the future development of the functional edible oils. The results were as follows:1. DPPH- spectrophotometric analysis was used to evaluate the antioxidant activities of 33 Chinese medicinal herb extracts. The results indicated that all herbs extracted by ethanol showed certain antioxidant activities and their activities varied from each other. Flos sophorae, Radix paeoniae rubra, Radix scutellariae, Flos lonicerae, Flos caryophylli and Folium ginkgo extracts have higher antioxidant activities than the others, and the six herbs showed no significant difference in antioxidant activities with vitamin E (p>0.05). However, the antioxidant activity of Flos sophorae extract was numerically higher than vitamin E. The antioxidant activities of Radix glycyrrhizae, Rhizoma coptidis, Fructus crataegi and Cortex phellodendri extracts were more than 90% of the antioxidant activities of vitamin E. Rhizoma pinelliae, Radix ophiopogonis, Semen pruni and Rhizoma dioscoreae extracts had lower antioxidant activities. DPPH- spectrophotometric analysis has many advantages in evaluating the antioxidant activities of Chinese medicinal herbs, including easy handling, high accuracy, high reproducibility and short reaction time.2. Radix scutellariae, Flos sophorae, Folium ginkgo powders and/or their combination were added to the peanut oil and sesame oil. The antioxidant activities of Radix scutellariae, Flos sophorae, Folium ginkgo, Radix scutellariae+Flos sophorae and Folium ginkgo+Flos sophorae in peanut oil and sesame oil were determined by Schaal oven-storage and free radical scavenging test. Meanwhile, Chinese medicinal herbs were added by the weight ratio of 6% and that of BHT is 0.03%. The combination of herbs was in the proportion of 1 I 1. The folio wing results were obtained:1) All Chinese medicinal herbs had certain antioxidant activities in oils. Among them, Radix scutellariae and Radix scutellariae+Flos sophorae in peanut oil, Flos sophorae, Folium ginkgo and Folium ginkgo+Flos sophorae in sesame oil had higher antioxidant activities, respectively.2) Different Chinese medicinal herbs had different antioxidant activities in peanut oil. The antioxidant activities of Radix scutellariae and Radix scutellariae+Flos sophorae were higher than BHT, but those of Flos sophorae, Folium ginkgo and Folium ginkgo+Flos sophorae were similar to BHT.3) Different Chinese medicinal herbs had different antioxidant activities in sesame oil. Among them, Radix scutellariae and Radix scutellariae+Flos sophorae had higher antioxidant activities than BHT, but those of Flos sophorae, Folium ginkgo and Folium ginkgo+Flos sophorae were similar to BHT.4) According to Arrhenius equation and the connection of reaction velocity constant and shelf lives, the shelf lives of peanut oil and sesame oil containing Chinese medicinal herb powders were forecasted. The shelf lives of oils added with herb powders could be prolongated to certain extent. The shelf life could be increased from 3.47 months for peanut oil to 9.32 months and from 4.84 months for sesame oil to 10.18 months at 20癈 when Radix scutellariae was...