Articles
Comparison of the postharvest quality of lettuce in a vertical farm or a greenhouse: some preliminary results
Article number
1458_10
Pages
73 – 80
Language
English
Abstract
Indoor vertical farms allow plants to be grown in a space-efficient way.
As these cultivation systems require a short growing cycle and compact growth, leafy vegetables are a popular crop choice.
However, little is known about the postharvest quality of indoor-grown lettuce.
In this preliminary study, the plant performance and postharvest phase of ‘Alyssa’ butterhead lettuce, grown in an indoor vertical farm, was compared to a crop cycle grown in a greenhouse during winter, with a similar fresh weight and dry weight used as prerequisites for this comparison.
At harvest, the total aerobic psychrotrophic count and the content of pigments, nitrate, and soluble sugars were determined.
The plants were shredded, and the respiration rate was measured during storage in the dark at 7°C (initial conditions 10% O2, balance N2). In addition, shredded lettuce from both cultivation systems was packed under equilibrium modified atmosphere packaging (EMAP) conditions at 3% O2 (balance N2) and the phytochemical contents were evaluated at different time points during dark storage at 4°C. While the dry weight percentage and the microbial contamination did not differ between the cultivation systems, plants grown in the vertical farm showed a reduction in respiration rate and nitrate content of about 25 and 75%, respectively.
The soluble sugar content was higher in plants grown in the vertical farm and remained higher than in greenhouse-grown plants during EMAP storage.
Chlorophyll and carotenoid contents showed no significant differences between the cultivation systems and did not change significantly during storage.
These preliminary results suggest that vertical farming may benefit the postharvest quality of produce.
As these cultivation systems require a short growing cycle and compact growth, leafy vegetables are a popular crop choice.
However, little is known about the postharvest quality of indoor-grown lettuce.
In this preliminary study, the plant performance and postharvest phase of ‘Alyssa’ butterhead lettuce, grown in an indoor vertical farm, was compared to a crop cycle grown in a greenhouse during winter, with a similar fresh weight and dry weight used as prerequisites for this comparison.
At harvest, the total aerobic psychrotrophic count and the content of pigments, nitrate, and soluble sugars were determined.
The plants were shredded, and the respiration rate was measured during storage in the dark at 7°C (initial conditions 10% O2, balance N2). In addition, shredded lettuce from both cultivation systems was packed under equilibrium modified atmosphere packaging (EMAP) conditions at 3% O2 (balance N2) and the phytochemical contents were evaluated at different time points during dark storage at 4°C. While the dry weight percentage and the microbial contamination did not differ between the cultivation systems, plants grown in the vertical farm showed a reduction in respiration rate and nitrate content of about 25 and 75%, respectively.
The soluble sugar content was higher in plants grown in the vertical farm and remained higher than in greenhouse-grown plants during EMAP storage.
Chlorophyll and carotenoid contents showed no significant differences between the cultivation systems and did not change significantly during storage.
These preliminary results suggest that vertical farming may benefit the postharvest quality of produce.
Authors
E. Van de Velde, F. Devlieghere, B. Deruyck, E. Tardy, K. Steppe, M.-C. Van Labeke, E. Dhooghe
Keywords
vertical farming, light spectrum, lettuce, nutritional quality, respiration, microbial contamination, shelf life
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