U.S. Farmers Switch Away from GM Seeds for Premium Niche

Rapeseed (Brassica napus) is abundantly grown in Europe, China, India, Canada and Australia.  The crop is cultivated for use as animal feed, biodiesel, and for human consumption as an edible vegetable oil.  While best known for its oil content, which has a high quality lipid composition, rapeseed also contains high-quality proteins comprised of essential amino acids.  These are found in rapeseed meal, the by-product of the extraction of oil from rapeseed.  
However, protein extracts in rapeseed have an intense, unpalatable bitter taste, which has deterred industry from employing the by-product in foods for human consumption. According to researchers at Germany’s Technical University of Munich (TUM), rapeseed includes very bitter-tasting secondary plant constituents.  In a recent study, the scientists identified three isolates in rapeseed meal: an extract of all the protein contained in rapeseed meal, an isolate containing predominantly cruciferin, and a third containing napin.  The isolates were found to have a protein content of 80-90%.  
Using mass spectrometric analysis methods and taste tests, the researchers identified the key substance responsible for the unpalatable bitterness as the compound kaempfrerol 3-0(2”-O-sinapoyl β-sophoroside).  The cruciferin isolate contained as much as 390 mg of kaempfrerol per kg.  Both the rapeseed meal and napin isolate tasted bitter in the sensory test, despite containing less than a tenth of the quantity of kaempfrerol. These finding was reported in the Journal of Agricultural and Food Chemistry.