Effetto della temperatura sulla conservazione della valerianella da IV gamma

The quality of minimally processed leafy vegetables is defined by the visual appearance and internal phytonutrient contents. The visual appearance depends on the chlorophyll content and other leaf pigments, while the phytonutrients include anthocyans, polyphenols and carotenoids. During the distribution chain the correct storage temperature can preserve for relatively long time the internal and external quality of minimally processed leafy vegetables. The aim of this work was to investigate the effect of two storage temperatures (4 and 10°C) on the quality of lamb’s lettuce (Valerianella olitoria L. Valerianella locusta ). Plants of the cv ‘Trofy’ were grown in floating system with the following nutrient solution concentration (expressed in mM): 13 N-NO3; 1.5 P; 3.5 Ca; 1.7 Mg; 9.5 Na; 8.0 Cl; 2.7 S; 0.04 Fe and micronutrients. The leaves were harvested at commercial maturity stage and minimally processed (washed, dried, graded). Then, they were packed in commercial plastic boxes and stored at 4 or 10°C. The effect of temperature was evaluated measuring the chlorophyll content and the variations of antioxidant compounds such as anthocyans, phenols and carotenoids. The anthocyans did not change in both storage temperatures, while the phenol content significantly decreased in leaves stored at 10°C after 8 days of storage. Total carotenoids, instead, decreased at both storage temperatures, but with different degradation rates.