Storage of intact heads prior to processing limits the shelf-life of fresh-cut Lactuca sativa L.

Abstract

Harvested lettuce heads are usually transported and stored for some period of time under a variety of conditions prior to processing. During storage, especially under suboptimal conditions, nutritional composition of the harvested produce continues to change. The possible impact of prior storage of the heads on the performance of the fresh-cut product has not been quantified, and was the aim of this study. The experiments were performed with three related genotypes of Lactuca sativa L. (butterhead lettuce): two green varieties and one red variety. The effect of prior storage on quality parameters in the stored whole heads and on subsequent fresh-cut quality performance was investigated. In addition, the effect of prior storage of heads with and without their root system and the application of light during storage were investigated. The changes in visual quality, the levels of energy reserves, and some selected senescence markers, i.e. chlorophyll content and electrolyte leakage were evaluated. Despite the relatively high storage temperature of 12°C, the intact heads still looked fresh even after 17 days of storage. However, a decline in the soluble sugars, a decrease in chlorophyll, and an increase in electrolyte leakage were observed with advancing storage duration. Prior storage of intact heads greatly decreased the shelf-life of the fresh-cut product prepared from these heads. Storage of rooted heads and the continuous application of light (above the light compensation point) did not alter the effect of prior storage of the heads on the quality of the fresh-cut product.