Physicochemical, Anti-Oxidant and Sensory Characteristics of Spiced Jam from Blends of Selected Tropical Fruits

Abstract

Jams are preserved fruits and sugars which are packaged in cans or bottles for long-term preservation. The processing involves the disruption of the fruit tissue followed by heating with water and sugar to activate the pectin prior being put into containers. Jams were processed from two selected tropical fruits namely, pineapple and watermelon. The jam produced was spiced with ginger and turmeric at 5% level using a standard methods. The treatments are WA (watermelon 100%), WAG (watermelon 95% + ginger 5%), WAT (Watermelon 95% + turmeric 5%), WAGT (watermelon 95% + ginger 5% + turmeric 5%), PI (pineapple 100%), PIG (pineapple 95 % + ginger 5%), PIT (pineapple 95% + turmeric 5%) and PIGT (pineapple 95% + ginger 5% + 5% turmeric). The proximate, physiochemical, antioxidant, total phenolic, color and sensory characteristics of the spiced jams were determined using standard analytical procedures. The proximate result showed that the moisture content of the samples ranged from 3.61-20.55% for Watermelon jam (WA) and reference sample (CNTP); protein 0.50-5.16% for (CNTP) and watermelon-ginger jam (WAG); fat and ash contents were 0.21-2.55% and 0.38-1.53% for (CNTP) and pineapple jam (PI) respectively. The pH of the spiced jam ranged from 3.10-3.40 for (CNTP) and (WAG) while the sugar brix ranged from 69.80-79.50° brix. The titratable acidity of the samples ranged from 1.03-1.06 g/ml for pineapple-turmeric jam (PIT) and (CNTP).The TSS/TTA ratio was 52.88 and 5.39 for (CNTP) and (WA) respectively. The antioxidant properties of the sample ranged between 31.39-50.67% for (WA) and (PIG). Total phenolic content was 0.14-0.25 MM GAE/ 100 ml for watermelon jam (WA) and (PIT). The L*, a* and b* values for the samples ranged from 23.23-33.16, 1.05-6.69 and 3.35-13.55. The result for sensory scores of the spiced jams ranged from 5.66-7.98 and 6.20-7.88 for color and taste respectively while the mouth feel was 5.05-7.46. The overall acceptability scores ranged from 6.40-7.90. Conclusively, pineapple and watermelon jams spiced with ginger and turmeric were nutritious and acceptable, however, pineapple-ginger jam was most nutritious and acceptable, hence, pineapple-ginger jam can be utilized as a functional food and can also contribute to the improvement of Nigeria food composition database.