Effects of hexanal, trans-2-hexenal, and storage temperature on shelf lifeof fresh sliced apples

In this paper, the effects of hexanal and trans-2-hexenal, which are both n atural molecules characterizing apple aroma, on the microbial population an d on color retention of fresh sliced apples were evaluated. In particular, a central composite design (CCD) was developed to assess the individual and interactive effects of the chosen volatile molecules and storage temperatu res on (i) the growth of the naturally occurring microflora, (ii) the evolu tion over time of an inoculated spoilage yeast (Pichia subpelliculosa), and (iii) the enzymatic browning reaction in minimally processed apples. The i nclusion of hexanal and trans-2-hexenal in the storage atmosphere of apple slices determined a significant extension of shelf life also when P. subpel liculosa was inoculated at levels of 10(3) colony-forming units/g and abusi ve storage temperatures were used. In fact, the presence of these molecules in the packaging atmospheres considerably prolonged the lag phases of the inoculated yeast and reduced the growth potential of naturally occurring ba cteria. Moreover, the addition to the modified atmosphere of low levels of the hexanal increased the color stability of the products up to 16 days.