Changes of antioxidant constituents in pineapple (Ananas comosus) residue during drying process

Brazil is one of the three largest producers of fruit in the world. As a consequence, it has become one of the largest producers of agricultural residues. Studies have shown that the residues of certain fruits can present a higher antioxidant activity than the pulp. Although these residues are usually discarded, it could be used as an alternative source of nutrients. The present paper investigates the drying of pineapple residues in a fixed-bed dryer, analyzing the effect of the process variables on the antioxidant properties of the residue. The content of phenolic compounds, flavonoids, and ascorbic acid were also quantified. The results shown that the drying of the fruit residue in a fixed-bed was very efficient. The content of some bioactive compounds was found to increase after drying. Therefore, a new type of product could somehow be considered helpful to promote the nutritional value and extend the utilization of residues. (C) 2013 Elsevier B.V. All rights reserved.