NUTRITIONAL CHARACTERISATION OF ROSELLE (HIBISCUS SABDARIFFA) CALYCES, EVALUATION OF ITS FUNCTIONAL PROPERTIES AND SENSORY QUALITY OF ITS NOVEL PRODUCTS

Abstract

Hibiscus sabdariffa L (roselle) is an important flowering plant in the Malvaceae family (FAO). But surprisingly verylittle fundamental research, in terms of cultivation, agronomy, productivity and various applications, has beencarried out in Kenya. The aim of this study was to determine the nutritional, chemical composition and bioactivecompounds in the calyces of roselle and evaluate its potential in development of roselle drinks. Properties ofroselle extract before and after pasteurization included pH of 3.88 ± 0.00 and 3.42 ± 0.01, total titratable acidity (asMalic acid) of 2.24 ± 0.00 and 2.24 ± 0.03 %, total phenolic content of 6.06 ± 0.18 and 5.82 ± 0.01 mg/g roselleextract, respectively. The antioxidant activities using DPPH assay with Ascorbic acid standard, expressed as EC50(efficient concentration), were 230.01 ± 2.40 and 235.34 ± 0.79 μg/ml respectively. Iron and calcium contents were28.5±0.3 and 14.83±0.60 mg/100 g respectively. Product formulations were done and their consumer acceptabilitydetermined based on a 9-point hedonic scale. After sensory analysis, the pure roselle drink was generally moreacceptable in all the sensory parameters. However, there was no significant differences at (p>0.05) with the otherdrinks mixed with orange, apple and melon. Upscaling cultivation of roselle in Kenya is recommended to enhanceits utilization as a product with functional properties. The roselle drinks products generally had high overallacceptability, thus a pointer to market success scenario.