Antifogging additives for greenhouse covers - effects on phytochemicals and nutritional quality of lettuce

Abstract

Antifogging additives are commercially used in greenhouse films to prevent water droplet formation on these films. This can increase light transmission, and thus, improve crop yield. However, the effect of polytunnels with antifogging additives on phytochemical content in lettuce (Lactuca sativa var. capitata ) is currently unclear. Here, polytunnels were chosen as a model to investigate the impact of antifogging additives in a completely randomized setting. Analysis by means of chromatographic methods coupled with mass spectrometry revealed a general influence of polytunnel cultivation compared to lettuces grown without a polytunnel on the content of phenolic compounds, photosynthetic pigments and fatty acids. The use of antifogging additives does not lead to significant differences in phenolic compounds and fatty acids. However, significant differences were observed for carotenoids and chlorophylls by both polytunnel cultivation and the use of antifogging additives. These differences probably occurred predominantly due to differences in light and temperature regimes related to polytunnel cultivation. Thus, due to polytunnels in general and the use of antifogging additives in particular, environmental conditions are created that impact valuable compounds and alter nutritional quality of crops.