Uso do micro-ondas de hidrodifusão e gravidade para secagem e extração das cultivares de uva e morango

Abstract

Red fruits are characterized by a high concentration of bioactive, low glycemic index. In addition, they become attractive due to their color (red to purple), due to the presence of anthocyanins (a major compound of phenolic compounds). Among the red fruits, the strawberry and the grape are highly consumed and are produced as jelly, ice cream, wine, among others. The present work aimed to evaluate the efficiency of the Microwave Hydrodiffusion and Gravity (MHG) on the production of pre-dehydrated fruit and fruit extract, providing products with high phenolic concentration and antioxidant capacity. For this, the moisture content, concentration of phenolic compounds, anthocyanins, antioxidant capacity and color of products obtained by MHG (pre-dried grape, grape extract, strawberry extract, strawberry co-product). Furthermore, based on the MHG process, an attempt was made to estimate the environmental impact and economic advantages of this process. For comparison, the same techniques were performed by the conventional process (oven drying, freeze drying, and organic solvent). We observed that the pre-dried grape by MHG reduced 50% of the moisture content in just 10 minutes, and simultaneous drying also provided the extract of the grape. Both products obtained showed high concentration of phenolic compounds and antioxidant capacity and a significant reduction in production time compared to conventional processes. In the extraction of strawberry by MHG, we observed that only one extraction step provides the extraction of 70% of anthocyanins from the fruit in just 15 minutes, but as the aim is to perform an exhaustive extraction, when using green solvents, we found that the solvents exhaustively extracted the anthocyanins from the strawberry. In addition, the co-product obtained after extractions may be reused, since it retained anthocyanin concentrations in it, being a potentially bioactive co-product. The MHG process also had a low environmental impact, due to the non-use of organic solvents and use of green solvents. Furthermore, the MHG proved to be economically advantageous, industrial scale use being economically viable considering the time of analysis, labor costs and financial return on products obtained. With that, at the end of this work, we concluded the efficiency in the use of MHG for the production of products with high phenolic concentrations and antioxidant capacity, this process being sustainable and economically viable.