Abstract: It is known that phenolic compounds possess a significant binding affinity for proteins. However, the protein- polyphenol interaction is the major cause of the dark colour and undesirable taste of vegetable protein products. Furthermore, it also influences functionality and nutritional bioavailability of food proteins. Flavonoids are the main phenolic compounds of wheat germ. Defatted wheat germ soluble proteins were prepared by two methods, and their flavonoid contents were determined, while 50% cold ethanol was tried to remove flavonoids in the protein products. The results showed that wheat germ albumins, globulins and protein isolates were obtained, and their protein contents were over 80%. The flavonoids content in wheat germ albumins was the highest, about 0.544%, while the protein isolates took the second place, and the globulins were the lowest. It was speculated that flavonoids in wheat germ mainly bound to albumins by certain interaction. The method of 50% ethanol could effectively remove the flavonoids in wheat germ soluble proteins, whereas 90% flavoniods were removed by washing three times.

Key words: defatted wheat germ, albumins, globulins, protein isolates, flavonoids