Quality changes in squid (Loligo duvaucelli) tubes chilled with dry ice and water ice

Study of chemical properties and evaluation of collagen in mantle, epidermal connective tissue and tentacle of Indian Squid, Loligo duvauceli Orbigny

The chemical composition and evaluation of Indian squid (Loligo duvauceli) mantle, epidermal connective tissue and tentacle is investigated in this current study. It is observed that squid mantle contains 22.2% total protein; 63.5% of the total protein is myofibrillar protein. The unique property of squid myofibrillar protein is its water solubility. Squid mantle contains 12.0% total collagen. Epidermal connective tissue has highest amounts of total collagen (17.8%). SDS-PAGE of total collagen identified high molecular weight α-, β- and γ- sub-chains. Amino acid profile analysis indicates that mantle and tentacle contain essential amino acids. Arginine forms a major portion of mantle collagen (272.5 g/100 g N). Isoleucine, glutamic acid and lysine are other amino acids that are found in significantly high amounts in the mantle. Sulphur containing cystine is deficit in mantle collagen. Papain digest of mantle and epidermal connective tissue is rich in uronic acid, while papain digest, collagenase digest and urea digest of epidermal connective tissue has significant amounts of sialic acid (25.2, 33.2 and 99.8 μmol /100 g, respectively). PAS staining of papain digest, collagenase digest and urea digest also identify the association of hexoses with low molecular weight collagen fragments. Histochemical sectioning also emphasized the localized distribution of collagen in epidermal and dermal region and very sparse fibres traverse the myotome bundles.

Microbiological quality of Cuttlefish (Sepia pharaonis) fillets stored in dry and wet ice

Microbiological quality of cuttlefish ( Sepia pharaonis) fillets stored in three different ice conditions was studied. Fillets stored in wet ice at a ratio of 1:1 (package III) were sensorially acceptable for only 18 h, while that stored in dry ice at 1:1 (package I) and combination of dry ice and wet ice at 1:0.2:0.5 (package II) were in acceptable condition up to 24 h without re-icing and thus there was an extension of shelf life by about 33%. Total bacterial load was 7 log10 cfu/g at the end of the storage period. Total psychrophilic population increased from zero to 7 log10 cfu/g while total lactic acid bacteria from zero to 5 log10 cfu/g. H2S producers were detected only at 18 h, with a count of 1 log10 cfu/g. Sulphite-reducing Clostridia increased gradually from zero to 110 most probable number count/g. Fresh cuttlefish fillets carried a bacterial flora of Micrococcus, Planococcus, Streptococcus, Moraxella, Proteus and Aeromonas. Pseudomonas was dominant in wet ice pack, while Aeromonas was dominant in both the dry ice and combination pack. Immediately after packing, the temperatures recorded in packages I, II and III were 10.5, 1.2 and 3.0 °C, respectively, which drastically decreased in 1 h and then maintained and finally increased gradually. The results indicate that use of combination of dry ice and wet ice is economical and very much useful to seafood industries, as this package considerably reduced the cost of air freight, as well as improved the quality and shelf life of cuttlefish.

Chemical composition of European squid and effects of different frozen storage temperatures on oxidative stability and fatty acid composition

The chemical composition of European squid (Loligo vulgaris) mantles and tentacles and the lipid oxidation during frozen storage at three different temperatures (-20º, -40º and -80 °C) were investigated. The moisture, fat, protein and ash contents of tentacles were 80.72%, 1.44%, 16.16% and 1.63% while the same contents for mantle were 78.54%, 1.37%, 18.52% and 1.45% respectively. The initial free fatty acidity (FFA), peroxide (PV) and thiobarbituric acid reactive substances (TBARS) values of tentacles were 1.17%, 1.80 meq O2/kg fat and 0.80 mg malonaldehyde/kg respectively. The same results for mantles were 1.38%, 2.20 meq O2/kg fat and 0.73 mg malonaldehyde/kg respectively. PV and TBARS values increased with the storage time for all samples and higher storage temperature resulted with higher PV and TBARS values. The initial fatty acid compositions of L. vulgaris mantles were 29.95% saturated (SFAs), 9.95% monounsaturated (MUFAs) and 59.31% polyunsaturated fatty acids (PUFAs) and tentacles were 34.16% SFAs, 10.69% MUFAs and 55.15 PUFAs. SFAs content were increased but MUFAs and PUFAs contents were decreased during frozen storage of mantles and tentacles.