Color, texture, rehydration ability and phenolic compounds of plums partially osmodehydrated and finish-dried by hot air

M.M. RODRÍGUEZ; A. RODRÍGUEZ; R.H. MASCHERONI

JOURNAL OF FOOD PROCESSING AND PRESERVATION

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2015 vol. 39 p. 2647 - 2662

0145-8892

The aim of this study was to analyze the influence of the drying process by combinedmethods. Osmotic dehydration was performed using glucose or sorbitolsolutions at different concentrations (40 or 60 °Brix), temperatures (25 or 40C)and two fruit-to-syrup ratios (1:4 or 1:10). Hot air drying was performed at differenttemperatures (60, 70 or 80C). Dried plums were evaluated in terms of color,texture, rehydration ability, phenolic compounds (total phenols, flavonoids) andwater activity. The color was analyzed through two methods: colorimeter andimage analysis. The evaluations showed a decrease in luminosity and an increaseof reddening due to browning originated during the drying process. The imageanalysis was the most appropriate to evaluate the changes in color. Firmness ofplums increased in relation to fresh fruit and was more evident at higher dryingtemperature. High drying temperatures provoked a collapse of the plum structure,which hindered water absorption in the rehydration process. The phenolic compoundsin plums were conditioned by the drying temperature; the content ofphenols and flavonoids was higher when they were dried at 70C. Plumsosmodehydrated in sorbitol 60% w/w, with a fruit/syrup ratio of 1/10, at 25C andair dried at 70C obtained a high degree of dehydration and best maintainedquality attributes.