Microwave Assisted Processing of Mixed Mango and Pineapple Jam

Lai, Yong Ling (2023) Microwave Assisted Processing of Mixed Mango and Pineapple Jam. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

The use of microwave (MW) technology as an alternative to the traditional jam procedure by conventional heating is gaining interest to preserve fruit jam quality. This study aims to investigate the effect of MW power and processing time on the properties of mixed mango and pineapple jam. Mango and pineapple pulp with the 1:1 proportion were blended together with sugar, pectin and citric acid, and processed by MW heating at different MW power (400 W and 800 W) and processing time (2, 4, 6, 8, and 10 min). The physicochemical properties, reducing sugar, vitamin C content, total phenolic content (TPC), and antioxidant properties (DPPH and FRAP) of mixed fruit jam were evaluated. The optimal power and time of the MW processing was determined and the optimised MW mixed fruit jam was compared with a commercial (CM) mixed fruit jam for proximate composition and sensory properties. The result showed that both MW power and processing time significantly (p < 0.05) affected pH, titratable acidity, water activity, total soluble solid (TSS), viscosity, moisture content, TPC, DPPH and FRAP. MW power of 800 W and processing time of 8 min and 10 min were pre-selected as the optimal process parameters as both met the requirement for pH 3.30, TSS (64.70–67.10 °Brix) and water activity (0.846–0.869) of fruit jam with the highest TPC (241.91–248.01 mg GAE/100 g DW) and FRAP (741.71–755.13 mg FE/100 g DW) contents among the MW jam. By comparing among the MW jam processed at 800 W and 8 min, MW jam processed at 800 W and 10 min, and CM jam, the MW jam were significantly different (p < 0.05) in crude fat, crude protein, carbohydrate and total energy contents compared to CM jam. Sensory test results showed that there was no significant difference (p > 0.05) in the colour, smell, taste, texture and overall acceptability between the MW and CM mixed fruit jam. Interestingly, 38% of the panellist preferred the MW jam processed at 800 MW power for 8 min among the jams, followed by 32% of the panellist preferred the MW jam processed at 800 MW power for 10 min, and only 30% of the panellist preferred the CM jam. The MW jam could compete favourably with CM jam. Microwave technology shows potential to be used for making fruit jam. Keywords: Mixed fruit jam, microwave, antioxidant, sensory properties