Quality evaluation of pulp powder and the developed functional jam from African locust bean fruit

Abstract

The pulp powder was prepared from fruits of African locust bean tree and used to produce jam. The pulp and jam were analyzed for the chemical composition, physicochemical, microbiological and sensory properties. The total soluble solids of the pulp and jam were 25.5 and 72.5 oBrix, respectively. The pulp had pH of 5.3, while the pH of the jam was 3.3. The jam had higher total titratable acidity than the pulp. The jam contained higher crude protein (3.16 %), crude fat (1.03%), ash (4.3%) and carbohydrate (76.044%) contents than the pulp. The crude protein, fat, ash and carbohydrate contents of the pulp were 2.86, 0.85, 2.93 and 68.81%, respectively. The energy content of the jam was also higher than that of the pulp. The flavonoids, carotenoids, tannins, oxalates, phytates, saponins and alkaloids contents of the jam were lower than those of the pulp. The total sugars, reducing sugars, glucose, fructose and sucrose contents of the pulp were 7.7, 10.7, 5. 5, 4.8 and 5.8%, respectively, while those of the jam were 75.5, 47.6, 20.3, 30.3 and 21.68%, respectively. The vitamins B1, B2 and C contents of the pulp were 122, 35 and 35 mg/100g, respectively and decreased to 113, 10.2 and 22mg/100g, respectively, in the jam. The citric acid increased from 12.9 in the pulp to 15.6mg/100gin the jam. The P, K, Mg, Cu, Zn and Ca contents of the jam were higher than those of the pulp, while the Na and Fe contents of the pulp were higher than those of the jam. The total plate counts of the pulp and the pulp jam were 4.0 x104 and 1.2 x 101, respectively. The yeast and mould counts of pulp were 2.4 x104, while that of the jam was 0.3 x 101. The commercial plum jam was rated higher than the pulp jam for all the sensory attributes assessed except spreadability and overall acceptability.