Accelerated Shelf-life Testing to Predict Quality Loss in Romaine-type Lettuce

Abstract

The postharvest life of lettuce (Lactuca sativa) is variable and negatively affected by mechanical injury, incomplete cooling, and poor genetic quality. Lettuce breeders are developing cultivars with a longer shelf life and rely on subjective, destructive, and time-consuming methods for quality analysis. One method of accelerating quality evaluations is known as accelerated shelf-life testing (ASLT), which has the potential to assist breeders in assessing lettuce quality and shelf life. The objective of this research was to determine the quality traits that significantly affect shelf life to develop an ASLT procedure to rapidly assess the postharvest quality of lettuce accessions in breeding programs. In Test 1, Romaine lettuce quality was evaluated using one subjective and five objective parameters during storage at 5, 10, 15, or 20 °C. Results determined that weight loss, lightness*, and hue* angle were best correlated with the overall appearance rating, whereas storage at 10 or 15 °C differentiated the shelf-life potential quickly and without excessive deterioration. In Test 2, these objective characteristics and storage temperatures were used to study rates of quality deterioration of a commercial Romaine cultivar (Okeechobee) and a breeding line (60182), both with long shelf lives, and a Batavia lettuce cultivar (La Brillante) with a short shelf life. Lettuce was evaluated during storage at 10 °C (winter and spring seasons) or at 15 °C (winter season). Weight loss was the most appropriate quality index for lettuce at these storage temperatures for a single harvest, whereas lightness* and hue* angle were the most appropriate indices for comparing quality between harvests. To apply ASLT to postharvest assessments of lettuce, breeders and other researchers should include two controls with good and poor shelf life (similar to ‘Okeechobee’ and ‘La Brillante’, respectively) as standard baseline cultivars during storage at either 10 or 15 °C.

Examining preharvest genetic and morphological factors contributing to lettuce (Lactuca sativa L.) shelf-life

“…1 a–c). These genotypes were selected from a larger set of romaine genotypes based on genotypic variability in their shelf-life 47 . Breeding line 60184 has a relatively short shelf-life (SSL), ‘Manatee’ has an intermediate shelf-life length (ISL), and ‘Okeechobee’ has a longer shelf-life (LSL) (Fig.…”

“…To determine shelf-life length, experiments, lettuce heads were harvested approximately 60 days after planting. Lettuce heads were collected and stored at 15 °C, as previously described 47 . Lettuce shelf-life was evaluated using a rating scale of 0 to 9, where 9 = lettuce heads free of damage and 0 = lettuce heads completely decayed.…”

Effect of Maturity Stages on the Quality of Cold Storage Iceberg Lettuce (Lactuca sativa var. capitate) for Export

“…The sensory analyses of the iceberg lettuce were carried out following the procedures of Aguero et al (2011) and Belisle et al (2021). Then, visual qualities, namely color, taste, internal and external morphology, and freshness, of the iceberg lettuce were assessed and scored following a 9-point rating scale with 9: excellent, 7: good, 5: fair, 3: poor, and 1: extremely poor.…”