Spray drying of grape juice: Microencapsulation of anthocyanin

Abstract

Drying of fruit juices by spray drying is a complicated process due to high hygroscopicity and stickiness of the resultant powders, which causes manipulation problems and damage to product quality. An alternative to optimize the process of spray drying is to add carrier agents, which also have the function of encapsulate active compounds. Grape juice has a high content of anthocyanins, with high antioxidant capacity and potential as a natural dye, however, their application is somewhat limited due to their low stability. In such a way, the use of carrier agents for the production of powdered grape juice is also important to preserve the anthocyanins. The aim of this project is obtain grape juice powder through the process of spray drying using maltodextrin, whey protein isolado and soy protein isolate as carriers, in order to protect the anthocyanins and obtain a product with good stability in relation to physical and chemical changes. The influence of process conditions and addition of encapsulating materials on the quality of the final dried product will be assessed. The products to be evaluated will be extracted from Vitis vinifera and Vitis lambrusca grape varieties, the first intended for the national market, American and Asian, while the second is directed for the European market. The product quality will be evaluated by measuring size and particle morphology, color, solubility, product yield and retention of anthocyanins sorption isotherms, glass transition temperature and stability of anthocyanin exposed to light and storage at different relative moisture.