Quality Evaluation of Mixed Pineapple and Red Dragon Fruit Jam

Chan, Yen Leng (2020) Quality Evaluation of Mixed Pineapple and Red Dragon Fruit Jam. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

A comparative study was conducted on mixed fruit jam with the different ratios of pineapple and red dragon fruit (100:0, 40:60, 50:50, 60:40 and 0:100). This study aims to investigate the possibility of producing a mixed fruit jam from pineapple and red dragon fruit and to evaluate the product quality in terms of physico-chemical properties, vitamin C content, DPPH free radical scavenging activity, total phenolic content, proximate composition, total yeast and mold count, and consumer acceptability. The physico-chemical analyses of mixed pineapple and red dragon fruit jam showed that there are significant differences (p < 0.05) in titratable acidity (0.0554−0.1067%), water activity (0.5313−0.5707), total soluble solids (65.4−68.5%), a* value (0.9667−28.03), reducing sugar content (11.28−34.03%) and viscosity (1.513−5.544 Pa·s) between the samples. The vitamin C content, total phenolic content and DPPH free radical scavenging activity of the jam samples were in the range of 69.63−1743 mg/100 g, 8.374−28.04% and 63.0−115.4 mg GAE/100g. The proximate analysis of the jam showed that crude fat, crude protein and crude fiber of the jam samples have no significance differences (p > 0.05). Ash content ranged from 0.4144 to 0.5616%, moisture content ranged from 25.50 to 32.79% and carbohydrate content ranged from 64.15 to 71.70% have significant differences (p < 0.05) between the samples. There were no yeast and mold observed. Sensory evaluation by untrained panelists was used to indicate the consumer acceptability. There are no significance differences (p > 0.05) in sweetness, sourness, texture, aroma and overall acceptability but there is significance difference (p < 0.05) in appearance. Based on the preference test, most of the panelist preferred the mixed fruit jam at 50:50% (pineapple:red dragon fruit) followed by 0:100%, 40:60%, 60:40% and 100:0%. The mixed pineapple-red dragon fruit jam is potential to be further developed as a commercial product.