Modeling and optimization of solar-assisted heat pump drying of pumpkin slice

Abstract

PurposeTo reduce energy consumption, the time needed of drying, and the loss of ß-carotene content, and ascorbic acid content, response surface methodology (RSM) was employed for optimization.Design/methodology/approachTo reduce energy consumption, the time needed of drying, and the loss of ß-carotene content, and ascorbic acid content, response surface methodology (RSM) was employed for optimization.FindingsThe results show that the optimum solar-assisted heat pump drying (SAHPD) conditions for drying pumpkin slice were: drying temperature of 67.40 °C, loading density of 1.05 kg/m3, and material thickness of 4 mm. Under these conditions, slice of pumpkin were dried in 440.637 min, where the unit energy consumption, ascorbic acid content, and ß-carotene content were 16.737 kJ/g, 25.682 mg/ (100–g dried sample), and 10.202 mg/g, respectively. The structure of the samples dried using the optimized SAHPD method exhibited a more complete cell morphology than those dried using heat pump drying when examined using scanning electronic microscopy.Originality/valueThis suggests that the optimized SAHPD conditions used in this study are important for production and processing.

Comprehensive assessment of heat pump dryers for drying agricultural products

“…The solar-assisted heat pump dryer used to dry the pumpkin has given good results in reducing losses in beta-carotene content, because the content of beta-carotene in the dried sample was 10.202 mg/g. 40 Good results were also achieved by the solar-assisted heat pump dryer fabricated by Sevik 86 to dry parsley, strawberry, mint, and tomato. The result demonstrated that there was no substantial drop in the content of beta-carotene in dried products.…”

“…Beta-carotenes, vitamin C, phycocyanins, total phenol content, and polysaccharides are among the nutritional parameters frequently assessed in relation to recent studies on heat pump dryers. 34,40,54,61,65,83,84 These bioactive nutrients are highly sensitive to heat that is why they are frequently assessed to assure the quality of dried products. 85 Findings on the nutritional composition of dried biomaterials using heat pump dryers from recently published works are summarized in Table 3.…”

“…Solar‐assisted heat pump drying was also employed for drying pumpkins by Dai et al 40 Compared with a typical heat pump dryer, this dryer showed good results in reducing drying time by 40% and energy consumption. Hu et al 41 developed a solar‐assisted heat pump dryer to dry wolfberry.…”

“…Particular attention is therefore paid to the dried products to demonstrate whether the latter has been able to retain all of the properties after drying. Beta‐carotenes, vitamin C, phycocyanins, total phenol content, and polysaccharides are among the nutritional parameters frequently assessed in relation to recent studies on heat pump dryers 34,40,54,61,65,83,84 . These bioactive nutrients are highly sensitive to heat that is why they are frequently assessed to assure the quality of dried products 85 .…”

A review of solar and solar‐assisted drying of fresh produce: state of the art, drying kinetics, and product qualities

“…Without sacrificing dried food quality, SDIMD efficiently uses energy. In a study by Dai et al ., 50 the pumpkin slices were subjected to a solar‐assisted heat pump dryer (SAHPD), and the drying time and energy consumption were evaluated. The authors reported that the unit energy consumption for the SAHPD was 16.737 kJ g −1 , and the dried pumpkin slices exhibited a more complete cell morphology than those dried using a heat pump dryer (HPD).…”