Effects of Different Drying Temperatures and Extraction Conditions on the Antioxidative Components and Capabilities of Buntan (Citrus grandis Osbeck) Peel

• Main Authors: Chen, Yan-Zhi, 陳嬿至
• Other Authors: Chang, Yu-Wei
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/yqdrgw

碩士 === 國立臺灣海洋大學 === 食品科學系 === 107 === The peels are generally thought to be waste products. However, previous studies have revealed that these part have a large amount of antioxidant compounds. In this study, fresh buntan (Citrus grandis Osbeck) from Tainan City, Taiwan was used as a raw material. Freeze drying and hot air drying (60 & 110℃) methods were used to dry buntan peels then extracted with water and 75% ethanol. The changes of the extracts were compared in total phenolic contents (TPC), total flavonoid contents (TFC) and antioxidant activity (DPPH free radical-scavenging activity, ferric reducing antioxidant power and ferrous ion chelating ability), and then used high performance liquid chromatography-diode array detector (HPLC-DAD) method to analyze the amount of naringin and hesperidin in buntan. The 110°C air dried ethanol extract had the highest TPC (13.81 mg GAE/g). The ferrous ion chelating ability was 93% in the 60°C air dried ethanol extract, DPPH free radical-scavenging activity was 89%, the contents of naringin was the highest and hesperidin was preceded only by 60°C dried water extract. The 110°C air dried ethanol extract not only had highest TPC, but included plenty of TFC; DPPH free radical-scavenging activity and ferric reducing antioxidant power were superior to the freeze dried extract. The results indicated that there was an effect (p<0.05) of drying methods on retaining the antioxidant potential of these buntan peels. The antioxidant activity of the ethanol extracts was generally better than water extracts. The antioxidative results weren’t positively correlated with TPC, except the ferric reducing antioxidant power. Although the TPC and drying temperature was not the main factor of the antioxidant capacity in buntan peels, it still showed outstanding capacity. The 60°C dried ethanol extract was most potential one for natural antioxidants. The 110°C dried buntan peel was rich in antioxidant and aroma, which can be developed functional foods or added to foods.