Studies on the carotenoids and in vitro antioxidant capacity of palmyrah fruit pulp from mannar

Abstract

The pulp of palmyrah (Borassus flabellifer. L) fruits collected from Mannar in the North-West of Sri Lanka was used for the study. The 4 types of palmyrah fruit collected in Mannar, represented >95% of all fruit types of palmyrah. Carotenoids of palmyrah fruit pulp were separated by open column chromatography. Identification and quantification of the carotenoids were carried out using a scanning spectrophotometer with the aid of a standard uv-visible spectral bank for carotenoids. Type I, II-A and III fruit pulps showed spectra dominated by phytoene and neurosporene and were largely non-provitamin A. Type II-B fruit pulp showed spectra high in phytofluene and had a retinol equivalent of 9.8.100g-1 fresh weight from β-carotene and β-zeacarotene. The pulp contained both hydrophilic and lipophilic antioxidants with total antioxidant varying from 2.4-21.8 trolox equivalent.g-1 determined by the 2-21 azino-bis-benzothiozoline-6-sulphonic acid free radical cation (ABTS+̇). The antioxidant levels measured as trolox equivalents of the separated carotenoids gave values generally consistent with the extent of conjugation of double bonds.