Influence of blanching-osmotic dehydration treatments on volatile fractionof strawberries

The effects of steam (S) and microwave (MW) blanching and osmotic treatment s, applied either singularly or combined, on the volatile fraction of straw berry have been evaluated. Osmotic dehydration was carried out at atmospher ic conditions (OD) and by applying a vacuum pulse at the beginning of the p rocess (PVOD). Volatiles were obtained by a simultaneous distillation-extra ction procedure and identified/quantified by gas chromatography-mass spectr ometry. Esters and 2,5-dimethyl-4-hydroxy-3(2H)-furanone were the major com pounds. Differences in volatile concentration promoted by blanching and/or osmotic processes were evaluated. Osmotic treatments promote formation of e sters and furanones, differently for either OD or PVOD treatments, but this effect was greatly inhibited when osmosis was preceded by blanching. The k ind of blanching (MW or S) also affected the sample final volatile profile.