Effects of novel modified atmosphere packaging on lipid quality and stability of sardine (Sardina pilchardus) fillets

Modified atmosphere packaging (MAP) is an efficient method to increase shelf-life of fishery products by inhibiting bacterial growth and oxidative reactions. Beside the traditional gases used for MAP, novel gases such as argon (Ar) and nitrous oxide (N2O) were approved for food use in the European Union. The present research investigates the effect of MAP with unconventional gas mixtures, that previously positively affected microbial shelf-life, on colour, lipid oxidation and sensorial characteristics of sardine fillets during storage. Four atmosphere conditions were tested: Air (20.8% O2/79.2% N2), N2 (30% CO2/70% N2), N2O (30% CO2/70% N2O) and Ar (30% CO2/70% Ar). Samples were stored for 12 days at 3 °C. Results showed that the removal of oxygen significantly inhibited the oxidation process; however, most of the investigated parameters related to fat oxidation did not show any improvement, except for a slight decrease in lipid hydrolysis and improvement in sensory properties in the packaging containing Ar

VIRAL LOAD OF LYMPHOCYSTIVIRUS IN TARGET AND NON-TARGET TISSUES OF NATUALLY INFECTED GILTHEAD SEABREAM (SPARUS AURATA)

Lymphocystis disease virus (LCDV), (Lymphocystivirus, Iridoviridae) is the causative agent of lymphocystis, a chronic self-limiting disease described worldwide in over 125 species of fish. In the Mediterranean area, gilthead seabream (Sparus aurata) is the most affected species. Lymphocystivirus infection causes single or clustered tumour-like nodules that are localized to the skin and fins. Although lymphocystis is frequently benign, it may be responsible for significant economic losses related to poor growth rate, non-marketability of injured fish and secondary bacterial infections. Recent surveys have shown a systemic spread of the LCDV and a persistent infection in fish after recovery. The limited availability of effective techniques for the diagnosis and study of Lymphocystivirus, due to their poor and difficult cultivability in vitro, has long reduced the possibility to study this infection. The recent development of a real-time PCR suitable for the detection and quantitation of the LCDV DNA genome in tissues of clearly or hidden infected subjects, represents a valuable new tool for pathogenesis study of lymphocystis. The presence of viral DNA was investigated in target (pectoral and caudal fins) and non-target (spleen, brain, eye) tissues of 12 naturally infected gilthead seabream. The infected fish were ranked on the basis of presence of typical lesions (4 subjects), scarring due to the regressive phase of the disease (4 subjects) and absence of any clinical alterations (4 subjects). The viral DNA was detected in all tested fish and tissues. Different viral loads were detected in target and non-target tissues showing statistically higher amount of viral DNA in pectoral and caudal fins (106-107 viral DNA copies/\uf06dl) than that detected in internal organs (103-105 viral DNA copies/\uf06dl). The distribution of the viral genome showed a similar pattern regardless of the clinical stage of the fish. In the caudal-pectoral fins and spleen viral loads were detected in decreasing, but not statistically significant, values in diseased, in regression and recovered subjects, respectively. The viral DNA was always detected in recovered fish with variable values in different organs (102-107 viral DNA copies/\uf06dl) showing a persistent infection after symptom remission. The present study confirmed systemic and persistent infection adding a quantitative analysis

The impact of gas mixtures of Argon and Nitrous oxide (N2O) on quality parameters of sardine (Sardina pilchardus) fillets during refrigerated storage.

The effect of modified atmosphere packaging (MAP) with unconventional gas mixtures on the main qualitative parameters of sardine fillets during refrigerated storage was investigated. Four different atmospheres conditions were tested: air; 30% CO2+70% N2; 30% CO2+70% N2O and 30% CO2+70% Ar. All samples were packaged in polypropylene trays sealed with a high barrier film and stored at 2\u20134 \ub0C for 12 days. The quality and the freshness of sardine fillets packed in MAP were evaluated by microbiological, physical and chemical analyses after 0, 1, 2, 5, 6, 8 and 12 days of the storage period. The 2-thiobarbituric acid-reactive substances (TBARS) values for MAP samples were lower compared to air samples, reaching a final value of 1.09 mg malonaldehyde (MA)/kg and 3.39 mg MA/kg, respectively. The samples packed in Ar reached the fixed threshold for total mesophilic and psychrotrophic bacteria after 12 days of storage, resulting the best MAP condition adopted, able to increase the sardine shelf-life of 3 days with respect to the other tested conditions. Air packed samples showed significantly higher (p < 0.05) Hx content (50 mg/kg) compared to the rest of the MAP samples (20 mg/kg). At the end of the storage period, the sample packed in Ar showed a significantly lower value (p < 0.05) (around 40 mg/kg), than the other MAP conditions

Studying physical state of films based on casava starch and/or chitosan by dielectric and thermal properties and effects of pitanga leaf hydroethanolic extract

Cassava starch (CS) and chitosan (CH) are biopolymers used alone or blended (CS/CH) to produce films, thanks to their excellent film-forming properties. Their main physical properties have been characterized, but their physical and water state have not yet been studied. The objective of this research was to study the water and macromolecular physical state of CS, CH and CS/CH films by DSC and dielectric properties, after sorption isotherms determinations. Biopolymers and obtained films were also analyzed by SEM, FTIR, X-ray diffraction and gas permeability. Dielectric properties of active films containing pitanga leaves hydroethanolic extract were also analyzed. All films presented type II sorption isotherms. Glass transition temperature of films decreased with the increase of moisture content (Xw) following the Gordon and Taylor model. The dielectric constant behaves depending of the monolayer moisture content (Xm): increased linearly as a function of Xw when Xw &gt; Xm. For Xw ≤ Xm, the dielectric constant remained constant. An exponential relationship between α-relaxation and Tg was calculated