Optimization of Conditions for Plastein Reaction and Its Application in Improving the Flavor of Protein Hydrolyzates from Yellowfin Tuna

Investigating the influence of plastein reaction on reducing the bitterness and offending smell of protein hydrolysates from yellowfin tuna offal. Protein hydrolysates of yellowfin tuna offal was prepared firstly, then the factors including pH value, kinds of enzymes, temperature and substrate concentration on influencing the nitrogen recovery and bitterness were separately evaluated and the conditions were optimized by orthogonal array design. Changing of offending smell between control and treated group was finally determined by electronic nose system. Result showed that the optimized conditions of plastein reaction were set as follows: pH 5, substrate concentration 40 %, and temperature 42 °C, which could decrease the bitterness from 7 to 1 and maintained the nitrogen recovery at a high level around 82.16 ± 0.13 % and the offending smell had a great improvement as well.