Biochemical aspects in two minimally processed lettuces upon storage

Summary The browning process was studied in two cultivars of minimally processed lettuce ( Lactuca sativa var. capitata cv. Verpia and Lactuca sativa var. acephala cv. Lollo Rossa). The analyses were carried out upon storage at 4 °C in the dark. The first interesting result was the resistance to browning of excised leaves of Lollo Rossa, that did not present the typical symptoms of browning. Another important characteristic of Lollo Rossa lettuce was the higher antioxidant ability before storage. The results of biochemical characteristics obtained in this experiment did not show clear evidence supporting the biochemical model of tissue browning involving the sequential synthesis of phenolics and quinones that are regulated, respectively, by phenyl alanine ammonia‐lyase, polyphenol oxidase and/or peroxidase.