Distribution chain effects on quality parameters of organically grown tomatoes

Summary

In order to evaluate the effects of short, compared to medium or long distribution chains, on some quality parameters of organically grown fresh tomatoes, a post-harvest experiment was carried out by reproducing in the lab the most common temperature, relative humidity conditions and storage-transport times occurring in the real distribution chain of organic horticultural fresh products.
Organically grown tomatoes of the cv. Nerina harvested at three different ripening stages (mature green, turning, red) were subjected to conditions corresponding to a short (1 day at room temperature), a medium (cold storage for 2 days, followed by ripening at room temperature) and a long distribution chain (cold storage for 6 or 9 days, followed by ripening at room temperature). In addition fruits harvested at the three different ripening stage were also subjected to optimal storage condition (8°C, turning and red tomatoes; 13°C green tomatoes, all at 95% R.H.) for 16 days.
At the end of the post-harvest experiment fruits were analyzed for volatile aroma compounds, organic acids, ascorbic acid, soluble sugars, texture, phenolic compounds.
Conditions of medium and long distribution chain (harvest at the green stage and cold storage-transport) did not have a significant detrimental effect when compared to short chain on the formation of some key tomato odorants, such as the lipid-derived aroma compounds (among which (3Z)-3-hexenal, hexanal) and the carotenoid-derived volatiles (among which damascenone, b-ionone).
On the other hand, conditions of medium and long chain greatly inhibited the formation of other aroma compounds (such as 1-nitro-2-phenylethane and 2-isobutylthiazole, related to the amino acid metabolism), which showed markedly higher levels in vine ripened fruits (or at the end of the short chain experiment).
Another significant effect was observed on firmness: fruits subjected to medium or long chain tended to show a reduced firmness when compared to vine ripened tomatoes, at harvest or at the end of the short chain.
On the contrary biosynthesis of ascorbic acid was scarcely affected by the distribution chain conditions: green harvested tomatoes, subjected to cold storage and ripened at room temperature afterwards, were able to accumulate an amount of ascorbic acid similar to that observed in vine ripened fruits.
Acknowledgement: The present study was performed within the project BIOVITA (W.P.3.1- Supply chain of horticultural products) funded by the Italian Ministry of Agriculture, Food and Forestry Policy.