Determination of Antioxidant Activity for Red- and White-fleshed pomelo (Citrus Grandis)

Tan, Hui Wen (2019) Determination of Antioxidant Activity for Red- and White-fleshed pomelo (Citrus Grandis). Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Pomelo is a type of citrus fruit which is high in phytochemical compounds such as phenolic, flavonoid and ascorbic acid. The aim of this study was to determine and compare the antioxidant activity of different parts (outer peel, inner peel and pulp) of the red- and white-fleshed pomelo. The antioxidant activity was determined by using DPPH scavenging activity, total flavonoid content (TFC), total phenolic content (TPC) and ferric-reducing antioxidant power (FRAP) tests. Red-flesh pomelo had significantly higher antioxidant activity than white-flesh pomelo. The outer peel of both types of pomelo exhibited the highest antioxidant activity compared to the inner peel and pulp of pomelo in terms of DPPH, TPC, TFC and FRAP. The outer peel of red pomelo had 90.28% radical scavenging activity, 42.90mg GAE/g of DW for TPC, 2.68mg CE/g of DW for TFC and 68.61mg FE/g of DW for FRAP. There were significant differences in antioxidant activity (p<0.05) between the different parts of pomelo. Therefore, the citrus peel can be used as functional ingredients in food product due to its high natural antioxidants. In future study, the pomelo will be analysed for its anticancer properties and antimicrobial properties. Keywords: Pomelo, antioxidant activity, DPPH, TPC, TFC, FRAP