Shelf life of iceberg lettuce affected by hydro cooling and temperature of storage

Abstract

Pre cooling is applied to remove the field heat of harvested horticultural produces. The goal of this work was to determine the cooling curve and the effects of hydro cooling on quality and shelf life of iceberg lettuce ‘Lucy Brown’ stored at 5°C and 22°C. Through shelf life, it was determined the changes on accumulated fresh weight loss, leaf relative water content and total chlorophyll, total soluble sugars, reducing and non-reducing sugars, and starch. The field heat from iceberg lettuce heads was removed within the first 10 min when submerged into cooled water at 4°C. Hydro cooled lettuce heads accumulated water over the leaf surfaces resulting in higher rate of fresh weight loss during storage when compared to control. Lettuce stored at 5°C kept higher relative water content in the leaves throughout the shelf life. Hydro cooling treatment delayed the wilting of the external leaves in three and two days when stored at 5 and 22°C, respectively. Hydro cooling did not influence the decrease on total soluble sugars, reducing sugars, non-reducing sugars and starch throughout shelf life, but affected the leaf chlorophyll content. Independent of the temperature in which the ‘Lucy Brown’ iceberg lettuce will be stored, hydro cooling is recommended to prolong quality and shelf life.