Abstract Fishing products are characterized for being highly perishable; therefore, preservation methods are used to retain freshness, quality and extend shelf life. One of the factors that influences most on the loss of freshness, quality and shelf life, is storage temperature. This study evaluated the effect of storage temperature (0 °C and 5 °C) on the quality and shelf life of tilapia (Oreochromis niloticus) muscle during 20 days of storage. Adenosine 5’-triphosphate (ATP) and related compounds, K-value, pH, color, texture, water holding capacity (WHC), total volatile bases (TVB-N), and total count of mesophilic microorganisms were monitored. The results indicated that time and storage temperature had a significant effect (P < 0.05) on K-value, TVB-N, and total count of mesophilic microorganisms. The present study concludes that, by storing tilapia muscle at a lower temperature, a longer shelf life is produced, which implies that the product can be kept with good quality for a longer period of time. Likewise, the edible quality of tilapia muscle was affected by storage temperature, observing a shelf life of 16 days at 0 °C and 8 days at 5 °C.

Resumen Los productos pesqueros se caracterizan por ser altamente perecederos; por lo tanto, se utilizan métodos para conservar la frescura, la calidad y extender la vida útil. Uno de los factores que más influye en la pérdida de frescura, calidad y vida útil es la temperatura de almacenamiento. Este estudio evaluó el efecto de la temperatura de almacenamiento (0 °C y 5 °C) sobre la calidad y vida útil del músculo de tilapia (Ore ochromis niloticus) durante 20 días de almacenamiento. Se monitorearon el ATP (adenosina-5’-trifosfato) y compuestos relacionados, el indice K, el pH, el color, la textura, la capacidad de retención de agua (CRA), las bases volátiles totales (TVB-N) y el recuento total de microorganismos mesófilos. Los resultados indicaron que el tiempo y la temperatura de almacenamiento tuvieron un efecto significativo (P < 0.05) sobre el indice K, TVB-N y el recuento total de microorganismos mesófilos. En el presente estudio se concluye que al almacenar el músculo de tilapia a menor temperatura se produce una mayor vida útil, lo que implica que el producto se puede conservar con buena calidad por más tiempo. Asimismo, la calidad comestible del músculo de tilapia se vio afectada por la temperatura de almacenamiento, observándose una vida útil de 16 días a 0 °C y 8 días a 5 °C.

Abstract The aim of this research was to evaluate the effect of storage temperature (0 and 5°C) on the main metabolites and related parameters to rigor mortis in muscle of tilapia (Oreochromis niloticus). The rigor index (IR), adenosine 5’-triphosphate (ATP), glycogen, lactic acid, pH and texture were evaluated. The IR analysis was performed during 266 hours of storage at the two temperatures, while the rest of the parameters were monitored at 0 and at 48 hours of storage at both temperatures. It was found that both temperature and storage time, had a significant effect on IR, being more pronounced at 5°C compared to 0°C.

Resumen El objetivo de la presente investigación fue evaluar el efecto de la temperatura de almacenamiento (0 y 5ºC) sobre los principales metabolitos y parámetros relacionados con el rigor mortis del músculo de tilapia (Oreochromis niloticus). Se evaluó el índice de rigor (IR), adenosina 5´-trifosfato (ATP), glucógeno, ácido láctico, pH y textura. El análisis del IR se realizó durante 266 h de almacenamiento a las dos temperaturas, mientras que el resto de los parámetros se monitorearon al tiempo 0 y a las 48 h de almacenamiento en ambas temperaturas. Se encontró que tanto la temperatura como el tiempo de almacenamiento presentaron un efecto significativo sobre el IR, siendo más pronunciado a 5°C en comparación al de 0°C.

Abstract The present research work determined the effect of the stable and oscillating seawater temperature at three different levels (21, 24 and 28°C), on the physiological condition of the lion’s paw scallop Nodipecten subnodosus. For this, we evaluated the following physiological indicators: adenosine triphosphate content (ATP), glycogen and total carbohydrates, as well as muscle yield index (MYI) and adenylated energy charge, which were determined in the abductor muscle of organisms, extracted directly from the lagoon and after the treatments application. It was found that in the experiment, concentrations of ATP, glycogen content, total carbohydrates, and MYI decreased significantly (P<0.05) after the application of treatments. No effect of temperature level and application form (oscillating and constant) on MYI and CEA was found, however, glycogen content showed a significant affect only from the temperature level, being organisms exposed to 28°C statistically different from those of 24 and 21°C. In conclusion, only the acclimatization temperature level affected the physiological condition of the lion’s paw scallop, being the organisms acclimatized to 28°C the most affected.

Resumen El presente trabajo de investigación determinó el efecto de la temperatura estable y oscilante del agua de mar a tres diferentes niveles (21, 24 y 28°C), sobre la condición fisiológica de la almeja mano de león Nodipecten subnodosus. Para ello, se evaluaron los siguientes indicadores fisiológicos: contenido de adenosina trifosfato (ATP), glucógeno y carbohidratos totales, así como índice de rendimiento muscular (IRM) y carga energética adenilada (CEA), los cuales se determinaron en el músculo abductor de organismos extraídos directamente de la laguna y después de la aplicación de los tratamientos. Se encontró que, en el experimento, las concentraciones de ATP, contenido de glucógeno, carbohidratos totales, e IRM disminuyeron significantemente (P<0.05) después de la aplicación de los tratamientos. No se encontró un efecto del nivel de temperatura y la forma de aplicación (oscilante y constante) en el IRM y CEA, sin embargo, en el contenido de glucógeno se obtuvo un afecto significativo solo del nivel de temperatura, siendo los organismos sometidos a 28°C diferentes (P<0.05) a los de 24 y 21°C. Por lo tanto, se concluyó, que solo el nivel de temperatura de aclimatación afectó la condición fisiológica de la almeja mano de león, siendo los organismos aclimatados a 28°C los más afectados.

Abstract The aim of this study was to evaluate the effects of chitosan-tomato plant extract (C-TPE) edible coating (EC) applications on the physicochemical, microbiological, sensory and antioxidant capacity of chicken during storage. Edible coatings prepared with chitosan 1%, acetic acid 1%, glycerol and TPE (0.1 and 0.3%) were tested. The slices were submerged for 1 minute in different treatments (T1: C 1%; T2: C 1% + TPE 0.1%; T3: C 1% + TPE 0.3%; T4: control) and stored at 4 °C. At the end of the storage period, the treatments exhibited the greatest physicochemical and microbiological effects in the slices, reducing the microbial population relative to the control. The T2 treatment exhibited the highest antioxidant capacity, total phenolic content and overall acceptance. The results demonstrate that the application of C with the addition of a natural extract, such as those from the tomato plant, can be an alternative method for preserving chicken meat.

Abstract Different studies on obtaining protein concentrates or surimi from giant squid ( Dosidicus gigas) have reported that soft gels are obtained in comparison with other fish species. Therefore, the aim of this research was to investigate the effect of the setting (30 and 60 °C, for 0, 30, 60, and 90 min) on the gelling capacity as a possible alternative to improve the textural characteristics of the gels. Treatments at 60 °C (G4, G5, and G6) had a higher percentage of insoluble protein, while the electrophoretic profile showed the presence of high molecular weight (HMW) aggregates, as well as the decrease of myosin, paramyosin and actin bands as the incubation time was increased. Likewise, these systems presented a lower content of total sulfhydryl (TSH), which is attributed to the formation of disulfide bridges. The texture profile analysis (TPA) showed that the setting application affected the different parameters evaluated (strength, elasticity, and cohesiveness). Setting as pretreatment did not prove to be a good alternative for the gelling of proteins from giant squid mantle, since the control treatment (no setting) was that which exhibited better textural characteristics.

Abstract Fish consumption has increased in recent years. However, fish meat is highly perishable, which demonstrates the need for technologies to preserve its quality. Edible coatings (EC) might provide an alternative to extend the shelf life of fish. The goal of this study was to evaluate the effect of EC of chitosan (C) in combination with carvacrol (CAR) on the physical and microbiological changes of tilapia fillets. Fillets were submerged for two minutes in different treatments (T1: control; T2: C 2%; T3: C 2% + 0.125% CAR; T 4: C 2% + 0.25% CAR). At the end of storage, T1 and T2 showed the lowest values of total volatile bases (TVB). The color parameters L*, a* and b* varied from each treatment. The texture decreased and the different treatments reduced the microbial population in relation to the control; T3 and T4 were the most effective. These results show that the use of C with CAR might be an alternative method to preserve the quality and safety of tilapia fillets.

Avaliou-se o efeito do transporte em refrigeração por 48 horas e quatro dias de armazenamento sobre a qualidade e vida de prateleira da gônada do bivalve pata de leão, Nodipecten subnodosus. Determinou-se a composição centesimal, a adenosina 5'trifosfato (ATP) e afins, o índice K, bases voláteis totais (TVB-N), trimetilamina (TMA-N), pH, perfil de ácidos graxos e análise microbiológica. A Gônada apresentou uma importante composição de ácidos graxos essenciais e baixos níveis iniciais de ATP, enquanto o índice K manteve-se constante. Quanto a TVB -N e TMA- N, apenas as primeiras ultrapassaram os limites admissíveis. Os valores de pH não mostraram nenhuma mudança significativa durante o armazenamento e, apesar dos altos níveis de TVB -N, de acordo com a análise quantitativa e microbiológica TMA- N, a segurança do produto foi demonstrada após quatro dias sob as condições de transporte e armazenamento utilizado.

The effect of refrigerated 48h transport and 4 days storage on the quality and shelf life of the whole lion's paw scallop Nodipecten subnodosus gonad was evaluated. Proximal composition, adenosine 5´triphosphate (ATP) and related products, K-value, total volatile bases (TVB-N), trimethylamine (TMA-N), pH, fatty acid profile and microbiological analyses were quantified. Gonad holds a significant composition of essential fatty acids while levels of gonadal ATP were initially low; moreover, K-value of the gonad remained constant. With respect to TVB-N and TMA-N, only the former exceeded allowed limits. The pH level showed no significant variation during storage and, despite the high level of TVB-N, according to the TMA-N as well as microbiological analyses it was demonstrated innocuity after 4 days under the transportation and storage conditions utilized.