The drying methods can be generally divided into traditional and industrial classes. Despite its time-consuming and energy-demanding nature, drying approaches are necessary in the production of sustainable products with minimum water contents which can cause a dramatic decline in the weight and volume of the product, hence facilitating its storage and transport. Drying can prolong the useful life of food products and play a decisive role in agricultural products by evaporating their moisture content, hence meddling with the growth of the microbial agents which grow in humid media. Pumpkin is often distributed in the form of a raw vegetable, and a processed product (frozen, dried, puréed, or pre-cooked) to enhance its stability during storage. Hence, pumpkin fruits need to be kept either frozen or dried. The high moisture content of pumpkin (90.1 ± 0.3%), however, makes it prone to microbial decay. Additionally, due to its bioactive properties, carotenoids, and vitamins, pumpkin has beneficial effects on human health, including: reducing the risk of neurological, heart, and cancer diseases, the prevention of osteoporosis, and high blood pressure.

The presence of bioactive compounds in pumpkin shows it as a functional food or ingredient for the development of a variety of innovative food products with health-promoting properties.

This product contains highly bioactive compounds with health-boosting abilities such as polyphenols, antioxidant, carotenoids (mainly β-carotene), vitamins C and A, minerals, polysaccharides, and edible fibers. Pumpkin ( cucurbita maxima) is one of the most important crops all around the world. At the mentioned conditions, response variables of drying time, energy consumption, shrinkage, color, rehydration ratio, total phenol, antioxidant, and vitamin C contents were 72.53 min, 24.52 MJ/kg, 23%, 14.74, 4.97, 617.97 mg GA/100 g dw, 81.57%, and 4.02 mg/g dw, with a confidence level of 0.948, respectively. According to the results, optimal drying conditions involved a temperature of 70 ☌, air velocity of 0.69 m/s, and IR power of 750 W. Response surfaces and diagrams were also utilized to show the interactive influence of the independent variables with the response variables (drying time, energy consumption, shrinkage, total color variation, rehydration ratio, total phenol, antioxidant, and vitamin C contents). Analysis of variance (non-fitting factor and R 2 value) was employed to determine the desirability of the model. For optimization of the drying conditions, the influence of three levels of independent variables including air temperature (40, 55, and 70 ☌), air velocity (0.5, 1, and 1.5 m/s), and IR power (250, 500, and 750 W) were assessed by response surface method (RSM) through a face-centered central composite design. In this research, a convective/infrared (CV/IR) dryer was used to dry pumpkin slices.

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