Does freezing and thawing affect the volatile profile of strawberry fruit (Fragaria x ananassa Duch.)?

This research was aimed at determining if there were any changes in the volatile profile of strawberries cv. Camarosa, when subjected to various freezing and thawing treatments. Strawberries were cut in half, one half of the berries were frozen directly at -20 degrees C or -80 degrees C, or rapidly frozen in liquid nitrogen (N-2) (-196 degrees C). They were then stored overnight or for a week. Berries were later left to thaw at room temperature (natural thawing) for about 1 handsome were forced-thawed in a 30 degrees C water bath. Headspace volatile compounds were determined using an Atmospheric Pressure Chemical Ionisation-Mass Spectrometer (APCI-GPA) and validated with a Gas Chromatograph-Mass Spectrometer (GC-MS). In a comparison of thawed half berries and fresh berries, most esters such as hexyl acetate, ethyl methyl hexanoate, methyl acetate were increased significantly by week-long and not by overnight freeze/thaw treatments. Ethyl butyrate was not affected by any treatment. The abundance of aldehydes such as the acetaldehyde compounds was increased significantly when thawed naturally compared to when forced-thawed in all the cold storage treatments. (C) 2008 Elsevier B.V. All rights reserved.