this study the possibilities of freezing and thawing of cod heads before enzymatic hydrolysis and the effect on
the quality of resulting fractions was investigated. Cod heads were frozen minced or whole and kept in frozen
storage for 20-21 days, thawed by air (4 ºC for 20 hours) or water immersion (6-10 ºC for 3 hours) and
subsequently hydrolysed by Protamex® (30 or 60 minutes). Results showed that the tested pre-treatments like
mincing, freezing and thawing had no effect on the resulting protein hydrolysates fractions and no significant differences were found in the resulting yields and chemical composition of the hydrolysates.