Quality Evaluation of Jam Produced from Mixture of Orange and Black Plum Fruits

Abstract

The potential of some wild-growing indigenous fruits such as black-plum (Vitex doniana) has remained largely untapped. Jams are solid gels made from fruit pulp or juice, sugar and added pectin. The research work was aimed at producing Jam from mixture of orange and black plum fruits in different proportions. Standard methods were used for determination of physicochemical properties; pH, titratable acidity, specific gravity, total soluble solids, sweetness index. Proximate compositions; moisture, protein, lipids, ash, carbohydrate and crude fibre analyses were carried out using standard method of AOAC, Vitamin A and E were determined using UV-Visible spectroscopic method, Vitamin C was determined by iodine titration method. Mineral contents were analyzed by AAS and flame photometry. The 9-point hedonic scale questionnaire was used for sensory evaluation. Results of physicochemical analysis showed significant increase (P<0.05) in pH (4.15±0.11 and 4.53±0.11), total soluble solids (60.88±0.74 and 62.80±2.03) and sweetness index (40.68±0.05 and 47.95±0.15) of sample orange-black plum (70:30 and 55:45) respectively when compared with orange jam (100%). Significant decrease (P<0.05) was also observed in titratable acidity (1.31±0.2) and specific gravity (2.19±0.20) of orange-black plum (55:45) when compared orange jam (100%). Significant difference was observed in all the proximate parameters analyzed with the exception of crude fibre (P<0.05). Sensory evaluation indicated consumer acceptability in orange- black plum jam (55:45). Processing black plum into jam by mixing it with orange or other fruits may help in preserving as well as utilizing the numerous nutrients available in the fruit.