91A-8 |
Anthocyanin content, phenolic composition and antioxidant activity of Sorrel (Hibiscus sabdariffa) during maturation |
K. R. LAMBERT, J. C. Jackson, and I. A. Kahwa. Department of Chemistry, University of the West Indies, Mona Campus, Kingston 7, Jamaica Sorrel is a seasonal plant, which is of socio-economic value throughout the Caribbean. It is well known for its red coloration, which is attributed to its anthocyanin content. Recently, there has been increased interest in research on anthocyanins and other phenolic compounds because of their possible linkage to health benefits such as reduction in heart disease and cancer because of their antioxidant activity. A white variety of sorrel also exists, which may contain significant phenolic components that could have health benefits similarly to the red varieties. This study will evaluate the anthocyanin content, phenolic composition and antioxidant activity of sorrel at four stages of maturity. Three varieties of sorrel, traditional red (TRED), early bearing red (ERED) and white (WHTE) were sampled at the pre-flowering stage, as well as, 1 week, 3 weeks, and 5 weeks after flowering. Anthocyanin content and phenolic composition were determined using the pH-differential method and Folin Ciocalteau reagent respectively and quantified by absorbance spectroscopy. Antioxidant activity was assayed by fluorescence spectroscopy using 1,3-diethylthiobarbituric acid (DETBA). Anthocyanins were only observed in the TRED and ERED extracts, and levels in both increased with maturation. Phenolic composition was significant for all three varieties. All of the sorrel extracts exhibited antioxidant activity, resulting in the decline of lipid peroxidation. This was inferred based on the fluorescence of the (DETBA)-reactive species that was produced from the reaction of DETBA with aldehyde degradation products of lipid peroxidation. This research has implications for improving the diets and health of the Caribbean population and is expected to benefit the agricultural sector by adding value to sorrel currently produced and consumed.
Session 91A, Food Chemistry: Enzymes, vitamins and plant pigments
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