Lettuce (Lactuca sativa) is a nutritious leafy vegetable, rich in minerals and vitamins. It is now considered as one of the most important salad crops and is used particularly as the base for salad and grown around the world. Salad has short vegetation period, so several production cycles can be achieved during the year. It has sedative, diuretic and expectorant features and is beneficial for functioning of the cardiovascular and digestive systems. Among the other valuable compounds, lettuce contains vitamin C, one of the essential nutrients for humans. It is very important to store lettuce after harvest in the environment in which its nutritional value does not deteriorate. Therefore, the aim of this study was to assess the effect of different cold storage conditions on concentration of vitamin C in lettuce. Four cultivars of lettuce (Murai, Kitare, Carmesi and Levistro) were included in the experiment. Plants were grown under controlled conditions of a greenhouse to technological maturity, in growing cubes. After harvest, lettuce heads were stored in the refrigerator in two ways: 1) together with growing cube or 2) without growing cube. Every three days after the beginning of the storage period, at three time points in total, concentration of vitamin C was determined. These results were also compared to concentration of vitamin C in lettuce which was not harvested and continued growth in a greenhouse, in growing cubes, during the entire period. Storage conditions effected concentration of vitamin C to varying extent in different cultivars. In cultivar Murai concentration of vitamin C declined the least over time, regardless of storage conditions (the lowest recorded value was 60% since the beginning of storage period). In the other three cultivars concentrations of vitamin C were very similar in cold storage. However, the differences between cultivars were observed in lettuce stored with growing cubes in a greenhouse where Kitare and Murai had 98 – 80% of vitamin C in comparison with respective controls. In Carmesi and Levistro concentration of vitamin C declined much more (in Levistro to about 25%, and this cultivar had the highest initial concentration of vitamin C). Generally, the results showed that there was a decrease in the concentration of vitamin C in lettuce over time, but less when lettuce was stored in the refrigerator without a growing cube.

Vitamin C, lettuce cultivars, postharvest storage

Presentation: oral