Short-term high-light intensity and low temperature improve the quality and flavor of lettuce grown in plant factory.

Background: Lettuce holds a prominent position in the year-round supply of vegetables, offering a rich array of health-beneficial substances, such as dietary fiber, phenolic compounds, lactucopicrin and lactucin. As such, its flavor has garnered increasing attention. Balancing the enhancement of beneficial compounds with the reduction of undesirable taste is a key focus of scientific research. To investigate short-term management to improve the nutritional quality and flavor of lettuce, combinations of different light intensities (200, 500 and 800 μm ol m s) and temperatures (10 and 22 °C) were applied separately to 'Lollo Rosso' and 'Little Butter Lettuce' for 7 days before harvest.

Results: The results obtained showed that increasing light intensity at low temperatures decreased nitrate content and increased soluble sugar, soluble protein, anthocyanin and phenolic compound content. In the case of lettuce flavor, the bitterness-related metabolites such as lactucin and lactucopicrin were reduced with high light intensity at a low temperature of 10 °C. With this combination, the fructose and glucose contents increased, significantly improving lettuce flavor.

Conclusion: Higher light intensity combined with low temperature for 7 days before harvest effectively improved the nutritional quality and flavor of lettuce, suggesting its great potential for use in horticultural practices. © 2024 Society of Chemical Industry.