The effect of cold storage on volatile organic compounds (VOCs) emitted from intact peach fruit

Postharvest peach fruit aroma profile is heavily affected by several factors including storage temperature that, together with storage period, plays a key role in determining the organoleptic properties and the overall quality perceived by consumers. The effect of three storage temperatures (0.5, 5.5 and 20°C) applied during storage up to one month on peaches from three cultivars (‘Flaminia’, FL, ‘Regina di Londa’, RL, and ‘Red Haven’, RH) was evaluated in terms of volatile organic compound (VOC) emission from intact fruit. In addition, the ripening behaviour of the fruit has been monitored during post-cold storage (3 d of shelf-life at 20°C). Aroma profile was analysed via SPME (solid phase micro extraction) fibre technique by GC-MS. PLS-DA (partial least squares discriminant analysis) of the whole data set showed that samples belonging to different cultivars resulted well-separated, indicating that marked differences in terms of VOCs concentration between cultivars are present. FL samples appeared to be the poorest in terms of evolved aroma compounds in general. A more detailed analysis revealed that intact peaches, sampled immediately after cold storage, are characterized by a pronounced different aroma profile when compared with fruit kept for three additional days under shelf-life at 20°C and with control samples. After 0.5°C storage fruit maintain higher firmness and lower soluble solids content (SSC) than control, indicating that this temperature is effective in delaying the normal ripening also during shelf-life, as also demonstrated by the profile of aroma compounds emitted by the intact fruit. On the other hand, after storage at 5.5°C peaches have higher SSC and VOCs levels, indicating that these conditions induce an acceleration of the ripening syndrome as observed in other fruit species.