Proceedings Volume 2010 (format .pdf) - SimpBTH

54,54log N (N = NTG/g apple slices)3,532,521,512780,501 7 14Analysis moment (days)Control Apple slices+hexenal SR Apple slices+hexenal SS Apple slices+hexenal SEFSR- slow release, SS - spraying, SEF- electrostatic field sprayingFig. 1. Variation of total aerobic count for fresh-sliced apple treated with trans-2-hexenalthrough different methods of applications and storied at refrigeration temperaturesTrans-2-hexenal treatments of apple slices determined a significantextension of shelf life also when S. cerevisiae was inoculated at levels of 10 5colony-forming units/g. Moreover, trans-2-hexenal led to a yeast selection favoringspecies having a reduced spoilage potential due to their prevalent respiratoryactivity.The results of microbiological analysis showed that the presence of trans-2-hexenal sprayed in electrostatic field and storage at 4 °C totally inhibitedmesophilic bacteria and considerably prolonged the lag phase of psychotropicbacteria (fig. 2).After 14 days at 4°C following essential oil treatment no significantdifferences in trans-2-hexenal content or in sensory traits were detected by atrained panel between untreated and treated “Golden Delicious” apples. Trans-2-hexenal, which is a natural molecule characterizing apple aroma, did not affect fruitappearance, color, aw, firmness, dry matter content or titratable acidity.The presence of these natural compound molecules, trans-2-hexenal, in thestorage atmospheres considerably prolonged the lag phases of the inoculated yeastand reduced the growth potential of naturally occurring bacteria. Moreover, theaddition of low levels of the trans-2-hexenal increased the color stability of theproducts up to 14 days.Addition of trans-2-hexenal to minimally processed apple was also veryeffective in preventing browning reactions for at least 14 days at 4 °C. Nosignificant changes in hue angle values were observed in samples treated withtrans-2-hexenal, even after 14 days of storage at 4 °C (table 1).