Bioactive compounds during storage of fresh-cut spinach: the role of endogenous ascorbic acid in the improvement of product quality

Spinach is rich in bioactive constituents such as vitamin C, flavonoids and phenolic acids. In this work, the biochemical modifications occurring during one week of storage at 4 °C were evaluated both in intact and in fresh-cut spinach. Results showed that vitamin C concentration is less affected by storage in fresh-cut spinach with respect to intact spinach. MS/MS analysis showed that the main flavonoids are not modified during storage in intact leaves, while some of them increased significantly during storage in the fresh-cut samples. Fresh-cut spinach did not show color alteration even if PPO activity increased significantly during storage. This finding was related to the high ascorbic acid content, which delays the subsequent polymerization events. This finding was confirmed by the unaltered concentration of phenolic compounds in fresh-cut spinach during storage. In conclusion, data about nutritional content and visual performance concurrently suggest that spinach is a suitable species for marketing as a fresh-cut product.