Suitability for Ready-to-Eat Processing and Preservation of Six Green and Red Baby Leaves Cultivars and Evaluation of Their Antioxidant Value during Storage and after the Expiration Date

Abstract

The physiological and chemical traits of three red (MS151, Copacabana and Excellent) and three green (Ortis 398, Summerbell and Babybell) baby leaf lettuce cultivars were evaluated during postharvest cold storage. In addition, their potential use as a source of antioxidants, after the expiration date, was also investigated. Red cultivars showed the best performance in terms of nutritional and physiological parameters. In particular, the antioxidant activity was 11-fold higher in red than in green baby leaf lettuces. Moreover, Ortis 398, MS151 and Copacabana, showing the lowest values for respiration rate, ammonium accumulation and electrolyte leakage, were selected as suitable for ready-to-eat processing and preservation. Finally, the cultivars Ortis 398, MS151 and Excellent were found to be of interest for the extraction of antioxidants due to their high phenol content. Practical Applications The selection of the most appropriate cultivars for ready-to-eat (RTE) salads is of primary importance in order to have good quality, to reduce storage losses and to have, after the expiration date, a produce still exploitable for the extraction of phytochemicals. Ortis 398, MS151 and Copacabana were selected, among the studied new baby leaves cultivars, for their particular aptitude for RTE processing. In addition, because RTE lettuce remains often unsold due to the loss of its fresh appearance, our results suggest the possibility to re-utilize the waste (after the expiration date) as a source of antioxidants. This could represent a practical application opportunity for the food industry. With this aim, the cultivars Ortis 398, MS151 and Excellent were selected for their high content in total polyphenols even after the expiration date.