Production and Quality Evaluation of Jam from Black Plum (Vitex doniana) Fruit
E. J. Anaeke
Department of Food Science and Technology, School of Engineering and Engineering Technology, Federal University of Technology, Owerri, Imo State, Nigeria.
G. N. Mofunanya
Department of Food Science and Technology, Faculty of Agriculture, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
C. C. Emejulu
Department of Food Science and Technology, Faculty of Agriculture, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
J. N. Nwosu
Department of Food Science and Technology, School of Engineering and Engineering Technology, Federal University of Technology, Owerri, Imo State, Nigeria.
C. C. Ezeji
Department of Food Science and Technology, School of Engineering and Engineering Technology, Federal University of Technology, Owerri, Imo State, Nigeria.
A. F. Ofoedum
*
Department of Food Science and Technology, School of Engineering and Engineering Technology, Federal University of Technology, Owerri, Imo State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Black plum (Vitex doniana) is an underutilized indigenous fruit with potential for value-added processing, particularly in regions where post-harvest losses are common. Its natural pectin content and nutritional properties make it a suitable raw material for jam production. This study evaluated the suitability of black plum (Vitex doniana) fruit for jam production using different proportions of ripe and unripe fruits. Three jam formulations were prepared: 100% ripe fruit jam (RHJ), 60% ripe and 40% unripe fruit jam (RSJ), and 40% ripe and 60% unripe fruit jam (RFJ). The jam samples were subjected to proximate, physicochemical and sensory analyses using standard procedures. The results showed that fruit maturity influenced the quality characteristics of the jam samples. Increasing the proportion of unripe fruit increased titratable acidity, pectin content and viscosity, while reducing sugar content and total soluble solids decreased. RFJ recorded the highest pectin content (8.91%) and viscosity (87.47 dynes/cm²), whereas RHJ had the highest reducing sugar content (54.41%) and total soluble solids (68.85 °Brix). Sensory evaluation showed that black plum jam compared favourably with commercial black currant-strawberry jam in taste and mouthfeel and had a higher aroma score. However, its overall acceptability was slightly lower because of its darker colour. The findings indicate that black plum fruit has useful natural pectin and acceptable sensory attributes for jam production. Processing black plum into jam may support value addition and improve the utilisation of this underexploited indigenous fruit.
Keywords: Vitex doniana, jam formulation, fruit maturity, pectin content, titratable acidity, viscosity, proximate composition, sensory acceptability, value addition