Microwave-assisted pulse vacuum method for grape drying

In recent years, multi-flash evaporation application by making use of sudden pressure changes during the microwave vacuum drying has become an important alternative to give puff structure to dried fruit and vegetable products and to solve the existing problems (low energy efficiency, product quality, etc.) in drying technology. In this study, it is aimed to determine the effect of process parameters such as flash drying temperature (70-80°C), microwave power (400-800 W) on drying behavior, drying energy efficiency and product quality characteristics during the drying of grapes by microwave assisted multiple flash drying (MWMFD) method. In this context, the drying curves of the grape samples were created by applying the MWMFD process. In addition, the effects of processing parameters on quality characteristics such as hydroxymethyl furfural (HMF) content, vitamin C losses, total phenolic content, total anthocyanin content, total flavonoid content and color change were determined statistically.