The aim of the present study was to evaluate the effect of solar and microwave drying on raspberries (Rubus Idaeus) cv. Heritage. The efficiency of drying was evaluated in terms of weight reduction in function of the time. The quality properties evaluated were color, texture, antioxidant capacity and total polyphenols content. The results showed that solar drying and microwave drying allowed a good preservation of surface color in the final product. However, the solar drying achieved a desirable texture in dried raspberries compared to microwave drying. Neither solar drying nor microwave drying allowed a high retention of the antioxidant capacity. Nevertheless, both processes allow obtaining final stable fruits (low water activity) at any time of the year.

Osmotic dehydration (OD) improves the organoleptic characteristics of products; nevertheless, depending on the product, the incorporation of great amounts of solute can be undesirable to consumers. The application of hydrogel coatings would overcome this, acting as a barrier to solute entering the product. An alginate–calcium chloride barrier system (A-CC) was tested with or without pretreatment of Ca²⁺ as a firmness agent applied to pumpkin sticks. Products were dehydrated in sucrose and glucose solutions (40 and 60% w/w). Different parameters were estimated such as soluble solids uptake, water content, and weight reduction; in addition, texture and microstructural changes were studied. The A-CC configuration complies with the barrier function to solids uptake from the dehydrating solution in case of 60% of sucrose, allowing water exit from the vegetal matrix. The pretreatment with Ca²⁺ contributed to the retention of product firmness. Integrity, adhesiveness, and thickness of the A-CC system during the OD process were evaluated by environmental scanning electron microscopy (ESEM). In this case, the coating thickness reduction was according to the product weight reduction, indicating that the coated product was dehydrated as an integrated system.