Physicochemical characterization and quantification of bioactive compounds of guava powder produced by cast-tape drying

Abstract

Guava (Psidium guajava L.) is one of the most nutritious fruits from tropical and subtropical regions; however, it is a seasonal and easily perishable fruit, besides not being produced worldwide. In this context, dehydration to produce powders simplifies product transportation and storage, however, the knowledge of bioactive compounds after drying is extremely important. Guava was dehydrated by a pilot scale cast-tape drying (CTD), a new low-cost dryer that allows the control of the spreading thickness, reducing significantly the drying time. Guava pulp was spread in CTD using 2 and 3 mm and dried at 98 °C to obtain powders with moisture contents of about 0.04 g/g (dry basis) and water activities close to 0.30. Powders obtained by CTD were compared to powders dried by freeze-drying (FD), and both drying processes, as well as guava pulp, showed high antioxidant activity and significant values of carotenoids and phenolic contents. Guava powders exhibited a wide range of particle sizes and flake-like structures, being easily dispersed in water, which indicates good rehydration properties of the products obtained from both drying methods. Therefore, CTD is a suitable process to produce guava powders with attractive properties, proving the preservation of important nutritional characteristics of the fruit.