Nutritional Composition of Roasted and Fermented Nigella sativa Seeds from Minna, Nigeria

Abstract

This work studied the proximate, mineral, amino acid profile, functional properties and phytochemical content of fermented and roasted Nigella sativa (black seed) using standard analytical methods. The seeds were divided into two; one portion was roasted at 100 ^oC for 15 mins while the second portion was fermented for 48 hours in the presence of yeast. The proximate analysis of the roasted and fermented samples revealed the values of moisture, ash, crude lipid, Crude protein, crude fibre, carbohydrate and calorific values of the fermented sample to be 1.72±0.18 %, 4.20±0.50 %, 37.27±0.59 %, 18.16±0.31 %, 5.08±0.25 %, 33.26±0.56 % and 474.49±0.19 kcal/100g while values for the roasted sample were 1.58±0.04 %, 4.67±0.07 %, 30.28±1.30 %, 17.28±0.31 %, 24.43±0.39 %, 22.09±0.37 % and 374.46±0.19 kcal/100g respectively. Mineral elements present were K (54.87±0.15 mg/100g), Mg (9.40±0.27 mg/100g), P (18.66±0.24 mg/100g), Na (3.24±0.24 mg/100g), Ca (11.95±0.21 mg/100g) and Fe (1.63±0.19 mg/100g) for the fermented sample and values obtained for K, Mg, P, Na, Ca and Fe in the roasted sample were 56.14±0.12, 7.65±0.13, 20.12±0.37, 3.75±0.17, 12.9±0.22 and 1.82±0.31 mg/100g respectively. Results of phytochemical content showed that fermented Nigella sativa contained phenol (271.09±0.26 mg/100g), tannins (14.21±0.78 mg/100 g), saponins (27.88±1.07 mg/100 g), flavonoids (25.06±0.71 mg/100 g) and alkaloids (9.40±1.03 mg/100 g) while phytochemical content of the roasted sample were 278.84 ± 0.74, 16.79±0.74, 26.06±1.16, 21.30±0.81 and 13.74±0.78 mg/100g for phenols tannins, saponins, flavonoids and alkaloids respectively. Measured values for bulk density, water absorption capacity, oil absorption capacity were 0.36±0.03 g/cm³, 3.00±0.04 % and 2.00±0.01 % for the fermented sample while 0.62±0.07g/cm³, 3.50±0.02 % and 1.00±0.03 % are the bulk density, water absorption capacity and oil absorption capacity respectively of the roasted sample. The amino acid profile revealed that the fermented sample had higher concentration of the essential amino acids compared to the roasted sample. Results obtained indicate that the consumption of N. sativa can contribute to the nutritional requirements of the body.