COMPARATIVE STUDIES ON THE NUTRIENT COMPOSITION OF SHADE- DRIED AND SUN-DRIED LEAVES OF ROSSELLE (HIBISCUS SABDARIFFA L.)

Abstract

Hibiscus sabdariffa, a leafy vegetable consumed extensively in Ghana, provides important source of micronutrients and essential amino acids in diets. Although sun-dried vegetables have been used as alternatives to green vegetables, no study has been done to ascertain the nutritional content against that of shade-dried leaves. This study determined nutritional composition of shade-dried and sun-dried leaves of Hibiscus sabdariffa (‘Bera’) to evaluate the various nutrients supplied, and their abilities to meet the recommended dietary allowance (RDA) for various age and physiological groups of people. Sun- and shade-dried leaves of Hibiscus sabdariffa were analyzed for their nutritional content using standard analytical methods. Mean values of protein, carbohydrates, ash, moisture and fibre for sun-dried leaves were 22.7, 42.2, 10.3, 8.1, 8.54 g/100g respectively, for shade-dried leaves, values were 1.6, 7.0, 1.4, 87.1, 1.6 g/100g respectively. Mean values of calcium, Iron, potassium, magnesium, phosphorus, and zinc were: sun-dried leaves; 411.0, 20.1, 39.3, 36.5, 54, 1.8 mg/100g; shade dried leaves values were: 65.6, 6.2, 5.6, 4.8, 14.1, 1.4 mg/100g. For RDA of nutrients per 100g sample, sun-dried leaves provided protein in the range of 32.0 – 206.4 %, carbohydrates 21.5 – 47.7 % and fibre, 29.4 – 47.6 %. For shade-dried leaves, protein was 2.3 – 14.2 %, carbohydrates 3.3 – 7.3 % and fibre 5.5 – 8.4 %. Percentage RDA of minerals supplied per 100g sample for various age and physiological groups were; sun-dried leaves,  Fe (74.6 – 287.6), Mg (8.7 – 48.7), Ca (31.6 – 152.2), P (4.3 – 19.6), K (770.6 – 5614.3), Zn (13.5 – 58.3); shade-dried leaves, Fe (23.9 – 89.0), Mg (1.1 – 6.4), Ca (5.0 – 24.3), P (1.1 – 5.1), K (110 – 801.4), Zn (11.0 - 47.7). The study indicates, sun-drying is a better method of preserving Hibiscus sabdariffa leaves. It could be included in diet to improve micronutrient intake which is a major problem in Ghana.