β-hydroxyacyl-CoA-dehydrogenase activity differentiates unfrozen from frozen-thawed Yellowfin tuna (Thunnus albacares)

Changes in the β-hydroxyacyl-CoAdehydrogenase (HADH) activity of fresh and frozen-thawed Yellowfin tuna were examined. A statistical approach to HADH activities determined in press juice allowed to set a critical value to differentiate fresh from frozen-thawed Yellowfin tuna: the threshold value was 3.7 U mL-1 at the probability level of 1%. The analysis of 37 tuna (not ready to eat) sampled on retail revealed the unconformity to labelling of 4 samples. A simple statistical algorithm was built to get probabilities from observed values on tuna of being or not frozen/thawed.