Abstract
| - Minimally processed products are more perishable than unprocessed rawmaterials and readilydeteriorate in quality, especially in color and texture. Theeffects of minimal processing on phenolicmetabolites have been studied on red lettuce. Three differenttissues of cv. Lollo Rosso wereseparated as white, green, and red and stored at 5 °C for 7−14days. The phenolic acids caffeoyltartaric, chlorogenic, dicaffeoyltartaric, and dicaffeoylquinic,the flavonoids quercetin 3-glucuronide, quercetin 3-glucoside, quercetin 3-(6-malonylglucoside), and thenew compound quercetin3-(6-malonylglucoside) 7-glucoside, and the anthocyanin cyanidin3-malonylglucoside were isolatedand identified in lettuce extracts. Phenolic compound content wasevaluated immediately aftercutting and after storage of the minimally processed products at 5°C. In midrib, wounding inducedan increase in phenylpropanoids during storage, particularly phenolicacids and anthocyanins. Onthe contrary, wounding did not induce significant changes in thecaffeic acid derivatives andflavonoids in green and red tissues. The anthocyanin contentdecreased in both green and red tissuesduring storage. Keywords: Lettuce; Lactuca sativa; Lollo Rosso; anthocyanins; phenolics;flavonoids; minimalprocessing; wound-induced changes; pigment stability;quality
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