Effects of extraction conditions on rosemary antioxidant capacity
學生姓名:
陳冠嘉
指導教授:
孫寶年
學期:
110下
摘 要:
Oil always takes a part in our daily lives. No matter which kind of food we eat, oil is used during cooking and seasoning. But oil oxidation is a big problem during heating or storage, it may cause the oil form rancidity flavors and toxic compounds, and so on. The addition of antioxidant is an efficient way to prevent the oxidation of oil. Salvia rosmarinus, rosemary, has been shown to be more effective than synthetic antioxidants
such as butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT). Therefore, the aim of this study was to compare the antioxidant capacity of rosemary among different extraction conditions. Different concentrations of ethanol, extraction periods were tested, and after the extraction process, total phenolic contents, total flavonoid contents, condensed tannin content, DPPH scavenging ability, inhibition of
conjugated diene, Trolox equivalent antioxidant capacity assay in the extracts were tested. Then, the rosemary extract was added into flaxseed oil to determine the oxidative stability with peroxide value and anisidine value. Ultrasonic extraction with 80 % ethanol for 30- min at 50 °C was the optimal condition for dried rosemary leaves. Three vegetable oils [high oleic soybean oil (HOSO), peanut oil (PO), cottonseed oil (CO)] and ethanol solution (75%) were used to extract rosemary’s antioxidants. After the extract process, the antioxidant concentrations were tested by HPLC-PDA; and then, the extracts were added into soybean oil and detect the iodine value, peroxide value and anisidine value to determine the better medium to extract rosemary’s antioxidants. HOSO contained more carnosic acid than CO and PO, but three extracts had comparable antioxidant efficacy. Overall, vegetable oils were better mediums for extracting rosemary’s antioxidants, and high olein soybean oil could extract more carnosic acid than peanut oil and cottonseed oil, but they had a comparable antioxidant capacity when tested on soybean oils’
oxidative stability.
such as butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT). Therefore, the aim of this study was to compare the antioxidant capacity of rosemary among different extraction conditions. Different concentrations of ethanol, extraction periods were tested, and after the extraction process, total phenolic contents, total flavonoid contents, condensed tannin content, DPPH scavenging ability, inhibition of
conjugated diene, Trolox equivalent antioxidant capacity assay in the extracts were tested. Then, the rosemary extract was added into flaxseed oil to determine the oxidative stability with peroxide value and anisidine value. Ultrasonic extraction with 80 % ethanol for 30- min at 50 °C was the optimal condition for dried rosemary leaves. Three vegetable oils [high oleic soybean oil (HOSO), peanut oil (PO), cottonseed oil (CO)] and ethanol solution (75%) were used to extract rosemary’s antioxidants. After the extract process, the antioxidant concentrations were tested by HPLC-PDA; and then, the extracts were added into soybean oil and detect the iodine value, peroxide value and anisidine value to determine the better medium to extract rosemary’s antioxidants. HOSO contained more carnosic acid than CO and PO, but three extracts had comparable antioxidant efficacy. Overall, vegetable oils were better mediums for extracting rosemary’s antioxidants, and high olein soybean oil could extract more carnosic acid than peanut oil and cottonseed oil, but they had a comparable antioxidant capacity when tested on soybean oils’
oxidative stability.
專題討論2022.03.09_陳冠嘉_摘要.pdf