Title: Differential effects of low humidity levels on butterhead quality indices related to external, middle and internal lettuce sections

Authors: Maria Victoria Aguero, Monica Viviana Barg, Alejandra Yommi, Sara I. Roura

Addresses: Grupo de Investigacion en Ingenieria en Alimentos, Facultad de Ingenieria, Universidad Nacional de Mar del Plata y CONICET, Juan B. Justo 4302, Mar del Plata, 7600, Argentina. ' Grupo Postcosecha, Instituto Nacional de Tecnologia Agricola (INTA), Unidad Experimental Balcarce, Ruta 226, Km 73.5, Balcarce, 7620, Argentina. ' Grupo Postcosecha, Instituto Nacional de Tecnologia Agricola (INTA), Unidad Experimental Balcarce, Ruta 226, Km 73.5, Balcarce, 7620, Argentina. ' Grupo de Investigacion en Ingenieria en Alimentos, Facultad de Ingenieria, Universidad Nacional de Mar del Plata y CONICET, Juan B. Justo 4302, Mar del Plata, 7600, Argentina

Abstract: Leaf water status evolution during greenhouse butterhead lettuce storage under adverse humidity conditions was evaluated. The relationships between water status and the chlorophyll content and overall visual quality (OVQ) were analysed. Parameters were evaluated in external, middle and internal sections of the lettuce heads. Indices showed different behaviour in different sections. There was a continuous decrease in the relative water content (RWC) in all sections. Decrement in water content (WC) was significantly higher in external section than in other sections. Increases were observed in bound water (BW) in all sections, probably representing a vegetable physiological response in order to control the amount of water loss. Chlorophyll in external section decreased following a first order kinetic. In external section, all parameters correlated with OVQ showing WC and RWC the highest correlation index; for middle section OVQ correlated with WC, RWC and free water (FW) while for internal section correlated only with WC.

Keywords: butterhead lettuce; leaf water status; chlorophyll degradation; overall visual quality; OVQ; shelf life; postharvest technology; lettuce sections; humidity levels; quality indices; greenhouse storage.

DOI: 10.1504/IJPTI.2010.038186

International Journal of Postharvest Technology and Innovation, 2010 Vol.2 No.1, pp.25 - 40

Published online: 21 Jan 2011 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article