Processing of feathers to proteins – from fundamental insight to application
Annually more than 1 million tons of feathers are produced as by-product from European poultry slaughterhouses. The amount of feather as by-product rises steadily with increasing poultry consumption. On the other hand, the increasing consumption of meat products requires more livestock and therefore also increasing amounts of protein rich feed is needed.
Feathers contain 85% - 90% keratin. Keratin is a structure protein which contains proteins needed by animals but it cannot be digested directly. Therefore hydrolysis of keratin is needed to make it digestible. In that process the disulphide bonds in the keratin are broken and amide bonds are broken to form more digestible smaller proteins, peptides and amino acids.
Processed feather proteins are used as feed ingredient for pet food, aqua diets and feed for fur animals. Eight essential amino acids in feather protein meal (ARG, ILE, LEU, PHE, THR, VAL TRP and CYS) are present in higher amounts than in fish meal. However, due to the unbalanced amino acid composition of feather, e.g. lack of three other essential amino acids, LYS, MET and HIS, feather meal is only part of complementary feed composition.
The conventional industrial feather protein processing method is thermal pressure hydrolysis. However, during the heating in that process the nutritional value of the feather proteins decreases significantly.
The aim of the project is to study the feather hydrolysis deeply and to obtain high nutritional value of feather proteins under industrially implementable production conditions.