Use of Ethanol in Convective Drying of Coated and Osmotically Dehydrated Papaya with Isomaltulose

Papaya is a tropical fruit with unique sensory characteristics and is an important source of bioactive compounds and antioxidants. Despite its beneficial health effects, the sale of papaya is limited due to its short shelf life and post-harvest losses. This study aimed to investigate the convective drying process of papaya that had been coated, osmotically dehydrated, and immersed in ethanol. The papaya cubes were coated with sodium alginate, osmotically dehydrated with isomaltulose (35% w/w; 300 min with vacuum application at 80 kPa for the first 20 min), and immersed in 95% ethanol for 2 min. Convective drying was then performed at 60 °C until a final moisture content of 13.02 ± 1.59% (w.b.). The drying process took between 240 and 340 min, and the kinetic behavior of all treatments was well represented by the Fick model with R² > 0.95. The use of ethanol significantly reduced drying time and, consequently, energy expenditure. The reduction in drying time was maximized when ethanol was used in conjunction with osmotic dehydration of both coated and uncoated samples, achieving a 30% reduction for a total drying time of 240 min. Osmotically dehydrated samples exhibited lower shrinkage, hardness, and effective diffusivity. Coating application resulted in better preservation of carotenoids, antioxidant activity, and phenolic compounds; however, leaching of these compounds, particularly ascorbic acid, was significant across all treatments. The results suggest that drying papaya using the treatment of edible coatings, osmotic dehydration and ethanol produced a dried product with satisfactory physical and nutritional quality at a reduced cost.