Study of vacuum-microwave drying (VMD) of late life fruits and vegetables
Fruit and vegetables are highly perishable commodities due to their high moisture content (around 80%) that deteriorate over a period of time if improperly handled. The uneaten food largely ends up in landfills, where it contributes to accumulating waste and creates methane, a powerful greenhouse gas. To recover the food waste and generate new value streams it is essential to first stabilize the food and prevent deterioration or spoilage.
To decrease the moisture content of a material, drying is required. A lower moisture leads to a decrease in the free water available for microbial activity. Consequently, spoilage micro-organisms are inactivated. Vacuum-Microwave drying (VMD), an emerging food dehydration method, involves incorporating microwave radiation in a conventional vacuum dryer for heating and evaporation of moisture instead of heating by conduction and convection. Compared to other techniques, VMD can greatly reduce the drying time without quality degradation. The process conditions required for optimal drying requires optimization studies for identifying the appropriate operating pressure and microwave power profiles, as well as batch size. Hence, the objective of the project is to reduce the drying time with maximum quality retention to the selected products used.