INFLUENCE OF OSMOTIC DEHYDRATION ON THE VOLATILE PROFILE OF GUAVA FRUITS

ABSTRACT

The effect of osmotic dehydration (OD) on the volatile compounds of guava fruits was studied. Osmotic treatments were carried out at atmospheric pressure, at continuous vacuum and by applying a vacuum pulse (5 min under vacuum and the remaining time at atmospheric pressure) at different temperatures (30, 40 and 50C) and times (1, 2 and 3 h). The volatile compounds of fresh and dehydrated samples were obtained by simultaneous distillation–extraction, and were analyzed by gas chromatography/mass spectrometry. In general, OD caused changes in the concentration of volatiles, depending on the process conditions. The use of lower temperatures and shorter treatment times can diminish the loss of volatiles with respect to the fresh samples. The greatest damage to volatiles loss is produced at 50C for up to 2 h under both pulsed and continuous vacuum. The lowest total volatiles loss occurred at 30 and 40C for up to 3 h under pulsed vacuum or atmospheric pressure.

PRACTICAL APPLICATIONS

Consumer demand for high‐quality products with freshlike characteristics has promoted the development of a new category, minimally processed fruits and vegetables. Although these products present, as distinguishing features, simplicity in use and convenience, they generally perish more quickly than the original raw material because of tissue damage caused by mechanical operations. The use of osmotic dehydration process has been presented as a tool for the development of minimally processed fruits. The slight water activity reduction promoted by the process may provide stable products with good nutritional and sensorial quality and with characteristics similar to those of the fresh products. The application of minimal processing to tropical fruits can represent an interesting world market. Fruit flavor is an important quality factor that influences consumer acceptability, and for this reason, its study is relevant in the minimally processed food product.