Determination of crude protein content using the Dumas method of rootless duckweed (Wolffia arrhiza) grown under different LED lights

Rootless duckweed (Wolffia spp.) has the potential high-protein food source for humans. Wolffia is a member of the Lemnaceae family and is the world's smallest spermatophyte, with reduced roots, stems, and leaves. Scientific research on Wolffia species is relatively new, and this species is believed to be rare in Turkey. The phytochemicals and nutritional composition of plants are significantly affected by environmental factors in the natural or cultivated medium. In this study, Wolffia arrhiza was collected and cultured from a local area in Yeşilırmak Delta (Samsun) grown under controlled conditions using different LED lights. The Dumas method was used to determine the amount of crude protein. The protein content, calculated by multiplying the nitrogen (%) content by the standard conversion factor 6.25, was also evaluated by using different conversion factors in the literature. The results showed that rootless duckweed can be successfully grown under artificial lighting conditions with different light spectrums. The protein content of rootless duckweed, which was around 10% in the natural environment, increased considerably under red LED light (41.6% protein). The effect of different lights on protein content of W. arrhiza was observed as red LED > blue LED > purple LED > fluorescent. With its high protein content, environmentally friendly and sustainable production, Wolffia has the potential to quickly take place in the plant-based protein and functional food market as an alternative to traditional crops in the near future.