Stability of sorbic and ascorbic acids in packed green table olives during long-term storage as affected by different packing conditions, and its influence on quality parameters

The effect of different packing conditions on sorbate stability was studied in Spanish-type green table olives stored for up to one year. The factors studied were preservation treatment (pasteurisation vs. non-pasteurisation), storage temperature (room temperature vs refrigeration), packaging material (glass bottle vs. plastic pouch), storage time, and the presence or not of an antioxidant additive (ascorbic acid). Sorbic acid was stable in pasteurised samples as well as in the refrigerated unpasteurised samples, both in the absence and in the presence of ascorbic acid. In unpasteurised samples stored at room temperature, sorbic acid gradually disappeared, with a concomitant increase in the concentration of trans-4-hexenoic acid, which could be attributable to the action of lactic acid bacteria. Ascorbic acid was always less stable than sorbate. Sorbate addition negatively affected the colour parameters of both fruit and brine. An appreciable off-flavour was detected in the samples in which sorbate had been degraded.