STUDY OF THE OSMOTIC DEHYDRATION PROCESS OF PINEAPPLE RINGS

摘要

The osmotic dehydration process of pineapple rings, at room temperature, wasrnfollowed during several hours in order to reach a defined sugar content by utilizing tworndifferent sample thickness: 1 and 2 cm, respectively. In all experimental runs, the waterrnloss, sugar gain and weight reduction were determined. The evolution of the threernprocess variables during the osmotic treatment (1:4, fruit:syrup ratio), allowed tornobserve changes in mass transfer rates. Based on water loss and sugar gain parameters,rnthe process reached constant values around 350 - 400 min.rnAt the beginning of the osmotic concentration treatment, both sugar gain andrnwater loss were very quick. Changes in rates suggested a two stage process, a first stagernfor the initial 150 minutes in which the water loss and sugar gain are higher; a secondrnstage through the 150 to 400 minutes in which the mass fluxes decreased progressively.rnAfter 400 min of process, around 29% of water loss, and 9% of sugar gain werernobserved. Sensory evaluations and process characteristics indicated a better osmoticrndehydration for pineapple samples of 1 cm.