Effects of two different processing methods on chemical composition and dry matter losses of Hibiscus sabdariffa L. (Roselle) seeds

Abstract

This study was carried out to evaluate effects of processing methods on chemical compositions and dry matter losses of Hibiscus sabdariffa L. seeds. Two processing methods (cooking and sprouting) with each having three different durations were adopted. There were seven treatments with unprocessed H. sabdariffa (control) and three cooking duration methods (30min, 60min and 90min) and three sprouting duration methods (3days, 6days and 9days) with each treatment having three replicates in a Completely Randomized Design (CRD). Results indicated that there was a significant (p < 0.05) differences observed for the mean values in all the parameters except dry matter. The dry matter losses of the processed seeds increased (p < 0.05) in sprouting and cooking with time, There was an (p < 0.05) increase in crude proteins and ash contents for the two processing methods but a (p < 0.05) decrease was observed for ether extract and fiber fractions. In addition, a (p < 0.05) decrease was observed for phytate contents in both processing methods. However, a (p < 0.05) decrease was observed for tannin content in cooking, whereas sprouting showed a significant increase in tannin levels. The cooking (p < 0.05) declined the oxalate content in H. sabdariffa seeds, and sprouting on a contrary had no effect on it. There was an (p < 0.05) increase in Phosphorus and Iron concentrations but a (p < 0.05) decrease was observed for magnesium and potassium concentrations as compared to the unprocessed seeds. It could be concluded that the two processing methods improved the nutritional quality of H. sabdariffa seeds, with some amount of losses in dry matter.

Keywords: Cooking, Sprouting, Chemical compositions, Mineral contents, Anti-nutrients, Dry matter losses