Fig. 5

Optimization of KerZ1-hydrolyzed feather system and analysis of hydrolysates. a Optimization of feather addition and feather morphology. b Feather shape display. 1: 100 g untreated feather, 2: 100 g feather treated with keratinase. c Contents of 16 common amino acids in hydrolysates obtained from different hydrolysis systems. d Types of peptides identified from hydrolysates obtained from a hydrolysis system containing 100 g/L of feathers. e Molecular weight distribution of peptides in the hydrolysate obtained from a hydrolysis system containing 100 g/L of feathers. f Possible biological functions corresponding to the peptides obtained from the database comparison