Microwave‐Assisted Foam Mat Drying of Guava Pulp: Drying Kinetics and Effect on Quality Attributes

Abstract

AbstractThe present study investigated the drying kinetics and quality of microwave foam mat‐dried guava powder using 8% egg albumin as the foaming agent. The foamed guava pulp was dried at microwave power of 480, 560, 640, 720 and 800W; foam thickness of 3, 5 and 7 mm; and inlet air temperature of 40 and 50C. Weight loss was used to estimate change in drying rate with respect to time. Reduction in drying time was observed with increase in microwave power and decrease in foam thickness. Powdered samples were analyzed for various physicochemical quality parameters viz. acidity, pH, total soluble solids (TSS), color change and ascorbic acid content. Statistical analysis using three‐way analysis of variance revealed that sample of 5 mm foam thickness dried at 800W and 50C was the best with 0.3584% total acid, 3.98 pH, 14 min drying time, 8°Brix TSS, 3.263 color change and 154.762 mg/100 g ascorbic acid content.Practical ApplicationsThese experiments show that the efficiency of foam mat drying, which has been shown to produce food powders with better results in terms of drying time and quality attributes, can be further improved tremendously if microwave power is used for heat generation. The microwave‐assisted foam mat‐dried guava powder was produced in extremely less time resulting in better quality of the final product. This work is the first attempt to exploit this technology for drying of guava pulp and further research needs to be carried out so that this technology of drying is exploited at industrial level.