Cambios en las propiedades fisicoquímicas de cuatro variedades de lechuga ( Lactuca sativa L.) durante el almacenamiento

Abstract

Lettuce, a popularly consumed leafy vegetable, is well known for its health and nutritional value. Thus, the current study focused on the qualitative changes of four lettuce varieties, namely Alpha, Parris Island, Graziella and Lollo Rossa, stored at 5.5 oC and 90 % RH for 12 days. The analyzed parameters were water content, total soluble solids (TSS), titrable acidity (TA), vitamin C, total phenols, polyphenoloxidase (PPO), color and texture. Under storage conditions, the studied varieties exhibited different rates of water loss. TSS was found to increase until day 8 of storage, which is also when TA differences were observed. The Graziella variety showed the highest vitamin C levels. Total phenol content decreased significantly during the 12 days of storage. No significant PPO activity changes were found, except for those of the Lollo Rossa variety. Biplot analysis allowed observing not only positive and negative correlations between coordinates L*, a* and b*, but also the separavtion of the green lettuce varieties from the red one, together with color variations depending on leaf position. Although textural changes were recorded at the end of the study, foliage quality was not altered. In short, the studied parameters, which contribute to lettu-ce direct consumption properties, can be said to be variety-dependent and better preserved under refrigeration.