Bioactive compounds and antioxidant capacities of phulae and nanglae pineapple

Bioactive compounds and antioxidant capacities of “Phulae” and “Nanglae” pineapple (Ananas comosus L. Merr) which are important geographical indications of Chiang Rai, Thailand were investigated. Two pineapple varieties were collected at 20-40 % yellow peel colour. Total soluble solids (TSS), titratable acidity (TA), total polyphenols, β-carotene, vitamin C and antioxidant capacity (ferric reducing antioxidant power (FRAP) assay and 2, 2-diphenyl-1-picrylhydrazil (DPPH assay) were analyzed in the fruit pulp. The TSS, TA and TSS/TA contents of both varieties were not significantly different. “Phulae” pineapple had vitamin C content, total polyphenol and β-carotene higher than “Nanglae” pineapple. However the antioxidant capacities (DPPH-assay and FRAP-assay) of “Phulae” were found to be significantly lower than “Nanglae” pineapple. This result indicates that vitamin C, phenolic compounds and β-carotene do not play a major role in the antioxidant capacity of pineapples and thus it may be a consequence of other bioactive compounds.