STUDIO DEI PARAMETRI QUALITATIVI E MARCATORI MOLECOLARI PER GLI ORTAGGI DI QUARTA GAMMA DURANTE LA CONSERVAZIONE

Variations of quality components and molecular markers of fresh-cut during storage The term of fresh cut refers to fruits and vegetables cut, washed and packed for immediate use. These products although remaining in a fresh state, are physically altered during processing operations and are characterized by an high metabolism and limited shelf life to 5-6 days. The quality parameters of these products are generally represented by antioxidants, vitamins, leaf pigments and volatile organic compounds. During storage, the quality factors of vegetables may be rapidly affected by the conditions of the post-harvest environment. The storage temperature and duration strongly influence the shelf life. In lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.), the chlorophyll a fluorescence (a rapid and non-destructive methods) has been used for monitoring product leaf quality during storage. Generally, the quality losses of leafy vegetable can be ascribed to senescence induced by oxidative stress and mechanical injury. Wounding significantly affects the ascorbic acid content in spinach leaves stored at 4 °C and at 20 °C to suggest that ascorbic acid is highly unstable and can be used as an indicator of freshness along the cut distribution chain. This result has been confirmed with a study conducted on enzyme and genes involved in the ascorbate-glutathione cycle for the ascorbic acid recycling. At molecular level promising results have been observed for SoSAG12 gene, as senescence markers of spinach leaves. A study on quality markers was also performed in tomato. Microarrays of Solanum lycopersicum have been used to identify genes up-regulated or down-regulated after cut operations (wounds) and associated with product deterioration. The genes differential expressed will be used as quality molecular markers in the fresh-cut distribution chain. Furthermore, has been conducted a study on tomato volatile organic compounds (VOCs). VOCs play an important role in plant product quality in terms of flavour and aroma or can be involved in sophisticated roles as signal molecules of damage and stress. Headspace trapping techniques combined with gas chromatography-mass spectrometry (GS-MS) has been used to identify changes in aroma compounds that occur in tomato (cv. Luna Rossa) at three different ripening stages after cut and during storage. Identifying these metabolites can result in a corresponding knowledge of genes responsible for their synthesis or their regulation in response to stress condition. However a gene expression analysis (qPCR) has been performed on the same samples to validate data.