RESUMEN
Lithodes santolla (SKC) and Paralomis granulosa (FSKC) are economically important resources exploited in southern South America. The effect of refrigerated storage (4 °C on flake ice) on physico-chemical (pH, thiobarbituric reactive substances (TBARs), total volatile basic nitrogen (TVB-N), water holding capacity (WHC), and water content (WC)), microbiological (total viable mesophilic bacteria (TVMC), psychrotrophic bacteria (TVPC), Staphylococcus spp, coliforms, enterobacteria, molds and yeasts) and sensory (odor, appearance, texture, juiciness, and taste) parameters was analyzed in the cooked SKC and FSKC merus. For each species, cooked merus from 36 animals were randomly distributed into 6 groups, corresponding to 0, 2, 5, 8, 11, and 14 days of storage. On each day, samples were taken for physico-chemical (n = 6), microbiological (n = 3), and sensory (n = 15) analyses. The pH values increased over time (P < 0.01 in both species), the TBARs only increased in FSKC (P = 0.008), whereas the TVB-N significantly rose only in SKC (P = 0.001). The WHC and the WC did not change over time for any of the king crab species (P > 0.05) in all cases. The presence of TVCM, TVCP, and Staphylococcus spp. in both species was observed from day 0. Furthermore, pathogenic microorganisms (S. aureus, coliforms, and enterobacteria) were not detected, and only the TVCP in SFKC reached the suggested microbial limit after 11 days. All sensory scores significantly decreased (P < 0.001) over time, but the quality of both king crab species remained acceptable until the 11th day. These findings suggest that the shelf-life of cooked merus was 11 and 8 days for SKC and SFKC, respectively, when stored at 4 °C with the presence of flake ice. These contributions consist of elucidating the shelf-life of these economically important seafood products and providing insights into their quality maintenance during storage.
RESUMEN
Several physiological processes can induce daily variations in aerobic metabolism. Lithodes santolla is a decapod crustacean of special concern since it is a sub-Antarctic species of commercial interest. The aim of this work was to study in L. santolla the daily variations in levels of enzymatic and non-enzymatic antioxidants, lipid peroxidation and protein oxidation, and haemolymphatic pH. Males of L. santolla of commercial size were randomly dissected every 4 h during a period of 24 h. Enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase and glutathione peroxidase were determined in samples of gills, muscle, hepatopancreas and haemolymph. Ascorbic acid, total glutathione, lipid peroxidation and protein oxidation were also determined in all tissues. Gills showed the highest enzymatic activity and hepatopancreas the highest concentration of non-enzymatic antioxidants. Maximum antioxidant activity was during the dark phase in gills and during the photophase in the haemolymph. Muscle showed significant daily variations, with peaks during the photophase and scotophase. Overall, an antioxidant protective mechanism is present in all tissues, where SOD and CAT represent the first line of defense. The defense mechanism in L. santolla seems to be more active during the dark phase, with slight differences among the analyzed tissues, indicating a higher metabolic rate.
Asunto(s)
Antioxidantes/metabolismo , Decápodos/fisiología , Animales , Ácido Ascórbico/metabolismo , Catalasa/metabolismo , Decápodos/enzimología , Decápodos/metabolismo , Branquias/enzimología , Branquias/metabolismo , Branquias/patología , Glutatión/metabolismo , Glutatión Peroxidasa/metabolismo , Glutatión Transferasa/metabolismo , Hemolinfa/enzimología , Hemolinfa/metabolismo , Hemolinfa/fisiología , Hepatopáncreas/enzimología , Hepatopáncreas/metabolismo , Hepatopáncreas/fisiología , Concentración de Iones de Hidrógeno , Peroxidación de Lípido , Masculino , Músculos/enzimología , Músculos/metabolismo , Músculos/fisiología , Oxidación-Reducción , Superóxido Dismutasa/metabolismoRESUMEN
In Tierra del Fuego (Southern South America), the stone or false king crab, Paralomis granulosa represents one of the most important crab fisheries. After capture, animals are kept in baskets and exposed to dryness for several hours, when the water flow through the gills is interrupted. As a consequence a concomitant increase of reactive oxygen species begins, triggering oxidative stress. The aim of this study was to determine oxidative stress and antioxidant enzyme activities due to air exposure in different tissues of P. granulosa. Fifty crabs (carapace length >82 mm) were captured in Beagle Channel (54 degrees 50'S, 68 degrees 20'W) during winter 2004. Five groups of 10 crabs each were exposed to dryness at 6 degrees C for 0, 3, 6, 12 or 24 h, respectively. Activity of superoxide dismutase (SOD), catalase (CAT), glutathione S transferase (GST) protein and lipid oxidation were measured in gills, muscle, hepatopancreas and haemolymph samples. Almost all analyzed tissues showed antioxidant enzymes activity, which varied with time of air exposure. The maximum enzyme activity was measured after 6 h of air exposure. Protein oxidation levels varied significantly in gills. Lipid peroxidation levels increased significantly in muscle and hepatopancreas. The critical time of air exposure probably occurs at 6 h. Thereafter animals were unable to induce the synthesis of antioxidant enzymes or proteins. This should be taken into account to minimize the stress generated by the commercial capture process.