Articles
Postharvest strategies to improve shelf-life of indoor-grown lettuce
Article number
1442_16
Pages
117 – 122
Language
English
Abstract
Lettuce (Lactuca sativa) cultivated in controlled environments, including greenhouses and vertical production systems, is frequently harvested with intact roots, a practice commonly referred to as living lettuce. This harvesting technique has been advocated as a means to extend its shelf life.
However, scientific data are limited to living lettuce shelf-life, postharvest quality, and food safety risks to consumers.
In this study, lettuce grown in a vertical, controlled environment system was harvested and subjected to four postharvest treatments to assess shelf-life and postharvest quality.
Treatments included storage inside or outside plastic clamshells and with or without roots.
The lettuce was stored for 28 days at 4°C and 85% relative humidity.
Fresh weight, weight loss, visual ratings, and colorimeter values (a*, b*, and c*) were measured every 3 days for the duration of the experiment.
In general, the fresh weight of lettuce plants decreased across all treatments as days in storage increased.
The root and clamshell treatments affected the fresh weight of the lettuce in storage.
In plants without roots, the clamshells had no impact on fresh weight.
However, fresh weight increased by 36% in plants with roots compared to those with absent roots.
A similar trend was observed for weight loss.
Lettuce stored in closed clamshells with roots had more intense green a* (-3.7 vs. -2.7), yellow b* (12.6 vs. 10.1), and were purer in color c* (13.3 vs. 10.5) compared to open clamshells with roots.
Understanding the factors involved in lettuce shelf-life and which factors have a greater influence on extending shelf-life will help to develop harvesting techniques that preserve both the shelf-life and food safety risks.
However, scientific data are limited to living lettuce shelf-life, postharvest quality, and food safety risks to consumers.
In this study, lettuce grown in a vertical, controlled environment system was harvested and subjected to four postharvest treatments to assess shelf-life and postharvest quality.
Treatments included storage inside or outside plastic clamshells and with or without roots.
The lettuce was stored for 28 days at 4°C and 85% relative humidity.
Fresh weight, weight loss, visual ratings, and colorimeter values (a*, b*, and c*) were measured every 3 days for the duration of the experiment.
In general, the fresh weight of lettuce plants decreased across all treatments as days in storage increased.
The root and clamshell treatments affected the fresh weight of the lettuce in storage.
In plants without roots, the clamshells had no impact on fresh weight.
However, fresh weight increased by 36% in plants with roots compared to those with absent roots.
A similar trend was observed for weight loss.
Lettuce stored in closed clamshells with roots had more intense green a* (-3.7 vs. -2.7), yellow b* (12.6 vs. 10.1), and were purer in color c* (13.3 vs. 10.5) compared to open clamshells with roots.
Understanding the factors involved in lettuce shelf-life and which factors have a greater influence on extending shelf-life will help to develop harvesting techniques that preserve both the shelf-life and food safety risks.
Authors
C. Rodrigues, C. Blanchard, M. Trandel-Hayse, D. Wells, T. Rehman
Keywords
root treatment, clamshell, controlled environment, lettuce
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