Indicators of protein spoilage in fresh and defrosted crustaceans and cephalopods stored in domestic condition.

In relation to consumer demand, crustaceans and cephalopods are sold as both fresh and defrosted. It is well known that total volatile basic nitrogen (TVB-N) and volatile amine values, especially, biogenic amines and biogenic amine index, are expression of freshness of fish products, but there is a lack of knowledge of their acceptability limits, for crustaceans and cephalopods. In order to assess these limits, real-time shelf life tests were carried out, relating the results of TVB-N, biogenic amines and BAI to the sensory evaluation of crustaceans and cuttlefishes, both fresh and defrosted. TVB-N and biogenic amines have been analysed in many shrimp species and cuttlefishes purchased in Perugia (Central Italy), and BAI was calculated as the ratio between different biogenic amines. The results show levels of TVB-N and spermine different between shrimp and cuttlefish (TVB-N: 37 vs . 14 mg/100 g; spermine: 4 vs . 14 mg/kg, respectively) while the other biogenic amines and BAI are close to zero in both. Among biogenic amines, cadaverine and even more putrescine significantly affect BAI values and seem to be the most effective in assessing limits of acceptability during storage.