A Comparative Study of the Antioxidant Properties of Three Pineapple (Ananas comosus L.) Varieties

The objective of this study was to determine the antioxidant activity of different pineapple varieties namely Josephine (Ananas comosus L. var. comosus cv. Josephine), Morris (Ananas comosus L. var. comosus cv. Morris), and Sarawak (Ananas comosus L. var. comosus cv. Sarawak). Different concentrations of methanol, ethanol, and acetone were used to extract the phenolic compounds. Folin Ciocalteu’s reagent was used to determine the total phenolic content. The ascorbic acid content of the fruit extracts was determined using the iodine titration method. The antioxidant activity of the pineapples was measured using the 2,2-diphenyl-1-picryhydrzyl (DPPH) radical scavenging assay, the Ferric Reducing Power (FRP) assay and the Ferrous Ion Chelating (FIC) assay. 50% methanol was chosen as the best solvent for extracting the phenolic compounds of the pineapples. Morris pineapple was found to contain the highest TPC (53.8±0.7 mg GAE/100g fruits) and antioxidant activity. This variety was also found to have the highest DPPH scavenging activity (25.2±0.5 mg AA/100g fruits), FRP (29.6 mg GAE/100g fruits) and FIC ability (8%/100g fruits). Despite having a higher TPC than the Sarawak variety, Josephine exhibited a low scavenging activity. Strong positive correlations (R2 = 0.9943) were observed between the ascorbic acid content and scavenging activity, as well as between TPC and FRP (R2 = 0.9475). Only a weak correlation (R2 = 0.158) was observed between corrected TPC and FRP. FIC ability was observed in all the extracts.Â