The purpose of this study was to determine the optimum amounts of vegetables to use for flavoring chicken head soup base. The effects of the amounts of ginger and onion on the sensory properties of chicken head soup base were examined, and the optimum amounts were determined using response surface methodology. Sensory properties that were evaluated were yellowness, turbidity, bloody flavor, chicken-brothiness, organ meat-like flavor, and sweet taste. The increased amounts of ginger and onion led to a decrease in bloody flavor and organ meat-like flavor. The optimum levels of ginger and onion were determined to be 40g and 50g, respectively. Chicken head soup base prepared with optimum amounts of vegetables contained more arginine, tryptophan, inosine monophosphate (IMP), and hypoxanthine than plain chicken head soup base. It also had less hexanal, which is related to fat rancidity.

Optimum preparation conditions for chicken head soup base were determined in terms of the effects of amount of chicken head and cooking time using response surface methodology based on sensory properties. Sensory properties that were evaluated were yellowness, turbidity, bloody, chicken-brothy, organ meat-like, and fat-like flavor. All values of sensory characteristics increased remarkably with an increase in the amount of chicken head and cooking time. The optimum amount of chicken head and cooking time were determined to be 1800 g and 150 minutes, respectively. Chicken head soup base had less fat, free amino acids, nucleotides, and its derivatives, but had significantly more cholesterol, sodium, and iron than whole chicken soup base. In flavor compound analysis, the amount of hexanal of the chicken head soup base, which is related to fat rancidity flavor, was 11-fold higher than that of the whole chicken soup base.