[Show abstract][Hide abstract] ABSTRACT: Three postharvest icing treatments were implemented on cuttlefish specimens (overall number = 243) after they were hauled onboard: T1-ICO, storage under a 15-mm-thick layer of contact crushed freshwater ice; T2-ICA, storage over a 15-mm-thick layer of contact crushed freshwater ice; T3-NOI, storage without any contact ice, but placed over a 15-mm-thick layer of contact crushed freshwater ice once ashore. All storage trials (n = 6) were conducted at 2 +/- 2 degrees C and were terminated on the sixth day of storage because the aim of the study was to evaluate the effect of realistic icing practices on the freshness quality and shelf-life of cuttlefish, as assessed by sensory (a non-destructive Quality Index Method, QIM), physical (dielectric properties through the Fish Freshness Meter, "295 - Torrymeter") and chemical (the breakdown products of adenosine 5'-triphosphate, or ATP, as well as relevant ratios among them) methods. The early use of contact ice, either above (T1-ICO) or underneath (T2-ICA) single-layered cuttlefish placed in self-draining polystyrene boxes, was able to slow down ATP degradation. Nevertheless, because three visual traits were significantly worsened in the former treatment, the T2-ICA treatment was suggested as the most proper icing procedure for this cephalopod. The Torrymeter readings had no utility either for predicting the cuttlefish actual/remaining shelf-life for each icing treatment, or for discriminating among them. The percentage ratio between hypoxanthine (Hx) and adenosine 5' monophosphate (AMP) proved to be the chemical index most highly correlated with ice days. A useful, non-destructive, QIM scheme for cuttlefish was successfully tried and tested in the process.
[Show abstract][Hide abstract] ABSTRACT: Each of ten batches of portion-size farmed European sea bass (overall number = 200, mean weight ± standard error = 312 ± 5 g; total length ± s.e. = 30.5 ± 0.3 cm) was randomly divided into four equally numbered subsamples (n = 5). Within batch, one subsample represented the raw reference (RW), while the others were allotted to oven broiling (OB), baking in aluminium foil (BF) or microwaving (MW), selected as mild cooking techniques and therefore among the preferred by Italian fish-eaters. Raw and cooked flesh composition as to proximates, fatty acids, selected minerals and water-soluble vitamins, as derived from OB, BF and MW, were combined with the relevant cooking yields to gain knowledge about the true retention values (TRVs) of these nutrients according to the “reference batch” approach, a well-established method for small-size seafood items as bivalve molluscs and crustaceans. Within the general context of high-yield cooking methods, BF proved to be the mildest, since it left the nutrient profile of sea bass flesh mostly unaffected compared to RW. The reference batch approach generated plausible TRVs for all the nutrients examined, most of which were significantly higher in BF than in OB, with MW data in between.
Full-text · Article · Jan 2013 · Lebensmittel-Wissenschaft und-Technologie
[Show abstract][Hide abstract] ABSTRACT: Lipid determination by the Smedes method was tested in an interlaboratory trial performed by nine laboratories from seven countries belonging to the West European Fish Technologists Association Analytical Methods Working Group. Five samples of fish and fishery products with different lipid contents, including two blind duplicates, were distributed among the participants. All laboratories applied a slightly modified Smedes method, which included extraction of lipids by cyclohexane and isopropanol, transfer of lipids to the cyclohexane phase by addition of water, phase separation by centrifugation, and gravimetric lipid determination. The results indicate that the RSD for reproducibility (RSD(R)) was between 4.11 and 6.31% for samples with moderate (7%) and high (14%) lipid content, depending on the sample. Larger SDs among the laboratories were obtained for a cod sample with low lipid content of 0.5%. The method is judged to be suitable as a routine method for lipid determination in fish and fishery products.
Full-text · Article · Apr 2012 · Journal of AOAC International
[Show abstract][Hide abstract] ABSTRACT: The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The (1)H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The fish metabolic profiles are studied by top-down chemometric analysis. The results of this exploratory investigation show that the fish metabolome accurately reflects the rearing conditions. The level of many metabolites co-vary with the rearing conditions and a few metabolites are quantified including glycogen (stress indicator), histidine, alanine and glycine which all display significant changes dependent on the aquaculture system and on the storage times.
[Show abstract][Hide abstract] ABSTRACT: The effects of the catching season (either Autumn/Winter or Spring) on lipid content, fatty acid profile and true retention values after oven baking were determined in anchovy (Engraulis encrasicholus), sardine (Sardina pilchardus), sprat (Sprattus sprattus) and horse mackerel (Trachurus trachurus) from the North Adriatic sea. In the raw state, the catching season induced significant changes in the flesh lipid contents of sardine and sprat. Anchovy was the species whose fatty acid composition of flesh lipids was most clearly affected by the season of catch. Oven baking had a significant, though rather modest, effect on some fatty acids and indices of sardine and anchovy lipids. When compared to the other species within the same season, spring sardine and winter sprat gave significantly higher true retention values for several individual fatty acids and some sums. Between 1 and 2.5 servings/week (depending on season) of either cooked anchovy, sardine, sprat, or 3 servings of cooked spring horse mackerel would suffice to satisfy human weekly requirements of EPA + DHA.
[Show abstract][Hide abstract] ABSTRACT: SummaryA combined refrigeration system consisting of ozone and flow ice was evaluated for the sacrifice, cooling and chilled storage of continental trout. The batch processed in ozonised flow ice exhibited significant (P < 0.05) reductions (0.97 and 1.51 log CFU cm−2) in skin aerobes and psychrotrophs on days 6 and 9, respectively, and significant (P < 0.05) reductions (0.94 log CFU g−1 and 0.96 log CFU g−1) in aerobes, and proteolytic bacteria in muscle on day 13. A significant (P < 0.05) inhibition of TMA-N formation after 9 days was also observed, with an average reduction of 28.4% along the storage period, Slight reductions in autolytic breakdown mechanisms were also observed in the ozonised batch, a maximum reduction of 14.82% being reached on day 13. The microbial and biochemical changes were well correlated with the sensory evaluation, which revealed relevant differences between the batches on day 13 and a shelf life extension of the ozonised batch up to day 16.
No preview · Article · Jul 2009 · International Journal of Food Science & Technology
[Show abstract][Hide abstract] ABSTRACT: Dorsal and ventral fillet portions (DP and VP, respectively) of European sea bass (Dicentrarchus labrax, ESB), gilthead sea bream (Sparus aurata, GSB), and rainbow trout (Oncorhynchus mykiss, RBT) were analysed for proximate constituents, and fatty acid composition and content.Moisture and lipid content differentiated DP from VP in all species. Significant differences emerged between DP and VP from ESB for MUFA, PUFA, and DHA contents. The n6/n3 ratio ranged from 0.22 (DP in RBT) to 0.38 (VP in GSB). The highest hypocholesterolaemic/hypercholesterolaemic fatty acid ratio pertained to DP and VP from RBT, and the lowest peroxidisability index to VP from GSB and ESB. The index of nutritional quality for EPA + DHA was always higher in VP than in DP, that of RBT being especially interesting because it is associated with a lower energy value than that from ESB and GSB.
[Show abstract][Hide abstract] ABSTRACT: The effect of yeast and chromium yeast on gilthead seabream (Sparus auratus L) performance, carcass indices and body composition was studied. Whether supplementation affected liver microsomal mixed function oxidases using either multibioprobes (testosterone) or highly specific substrates to cytochrome P450 (CYP) isoforms was also investigated. Seabream juveniles (35–37 g initial weight) were allocated into 12 800 L tanks of 50 fish each for 87 days and fed pelleted experimental diets, i.e. control, yeast supplemented (1.6%) and chromium yeast supplemented at both low (800 p.p.b.) and high chromium level (53 810 p.p.b.). At the end of the experiment, growth, feed conversion ratio, thermal-unit growth coefficient, carcass yield, hepatosomatic index, and carcass and fillet proximate compositions were similar among treatments and only condition factor was statistically different. Organic chromium at both doses affected CYP-catalysed drug reactions slightly, as shown by the modest effect on the regio- and stereoselective hydroxylations of testosterone, as well as the metabolism of the selected probes. Overall, we found that chromium yeast did not change performance substantially, nor carcass indices, carcass and fillet chemical compositions, or hepatic xenobiotic metabolizing enzymes of gilthead seabream.
Full-text · Article · Mar 2002 · Aquaculture Research
[Show abstract][Hide abstract] ABSTRACT: Aim of the present study was the evaluation of the effects of adding omega-3 fatty acids to a rabbit diet; as a omega-3 fatty acids source we used DHA-Gold™, obtained from a Schizochytrium microalgae, which contains 17.4% of DHA. Three-hundred Provisal rabbits were divided into 3 groups receiving in the 32 days before slaughter a commercial diet not added (T1) or added with DHA-Gold™ at 0.4% (T2 and at 0.8% (T3). Average daily gain was significantly increased (P< 0,01) by T2 compared to T1 (33.9 vs 32 g/d). Immediately after slaughtering, thigh and loin samples were collected from 8 animals of each group (4 males and 4 females); DHA content of samples was strongly influenced by treatment (19.1, 56 and 87.9 mg/100 g of thigh and 11, 34.4 and 52.8 mg/100 g of loin for T1, T2 and T3, respectively.
[Show abstract][Hide abstract] ABSTRACT: Recently, there has been an increasing interest in the potential effect of dietary chromium on the health of fish, particularly with respect to their metabolism and growth. Information as to the role of this mineral on their immune response, is limited however, so the aim of this study was to assess the effects of dietary chromium yeast supplementation on the immune response of rainbow trout (Oncorhynchus mykiss).Juvenile rainbow trout (56 g average weight) were fed three semipurified diets containing different levels of chromium (1540, 2340 and 4110 ppb), obtained by supplementing a basal diet with 800 or 2570 ppb chromium yeast, for 6 weeks. After this, time differences in their immune response were examined.A positive influence was observed on serum lysozyme activity at this time in fish maintained on the high chromium diet. The respiratory burst of head- kidney macrophages was also examined, and statistical differences were found in the level of respiratory burst elicited by macrophages from both groups of fish fed supplemented chromium after 3 and 6 weeks of feeding (absorbance at 3 weeks: 0·118, 0·166, 0·151 and 6 weeks 0·114, 0·168, 0·151 for the 1540, 2340 and 4110 ppb groups). Macrophages of fish receiving diets supplemented with chromium also had a greater ability to phagocytose yeast after 6 weeks than the control fish (40·5, 48 and 48·5% macrophages phagocytic in the 1540, 2340 and 4110 ppb groups, respectively).The results of the study show that chromium yeast is able to modulate the immune response of rainbow trout, and this effect appears to be both dose- and time-dependent.
Full-text · Article · Aug 2001 · Fish & Shellfish Immunology
[Show abstract][Hide abstract] ABSTRACT: The effect of refrigeration at 1°C on total lipid, phospholipid and fatty acid content of muscle was examined in 4 groups of sea bass (Dicentrarchus labrax) fed diets rich in fish oil and supplemented with increasing levels of vitamin E as antioxidant (139, 254, 495, and 942 ppm, respectively). After 1, 3, 6, 9 and 12 days refrigeration, muscle from the 4 sea bass groups contained increasing concentrations of vitamin E (on average 9.4, 13.1, 19.8 and 28.8 ppm) related to diet levels. However lipid parameters were unaffected until the end of the trial. The results indicate that the experimental conditions preserve lipid quality in sea bass muscle at least over the time range examined, irrespective of dietary formula.