The purpose of study was to determine the effects of osmotic dehydration process on polyphenols content in dried pears. The materials for the study involved samples of the fruits of Asian pears (Pyrus pyrifolia Nakai) cultivars: Hosui, Shinseiki and the fruits of European pears (Pyrus communis L.) cultivar Confenrence. Pears samples shaped as 10 mm were osmotic dehydrated in sucrose solution, pear concentrate and mixture of sucrose solution and pear concentrate (1:1). Temperature of osmotic dehydration of pears was at 20°C, during 1, 3 and 6 hours. Next, after dehydration fruits were dried at 70ºC temperature during 4,5 h. In fresh, osmo-dehydrated and dried of osmo-dehydrated pears total phenolics and phenolic compounds content were analyzed using the HPLC technique. Osmotic dehydration influenced in total phenolics content in the samples of pears. It was stated that dehydration in a solution of concentrated pears and and mixture of sucrose solution and pear concentrate increased total phenolics contents of the osmo-dehydrated fruits. Solution of sucrose had reduced total phenolics contents the more the longest dehydration lasted. After 6 h of osmotic dehydration of pears in sucrose solution 50% lost of phenolics content was observed. A convective drying process caused a decrease of the total phenolics content in comparison to basic material.
pear, polyphenols, dried, osmotic dehydration