The objective of this study was to develop a quality index method for Engraulis anchoita stored in ice and to determine its shelf-life based on this quality index method and chemical indices such as total volatile bases and thiobarbituric acid-reactive substances. Besides, the chemical composition with emphasis on the polyunsaturated fatty acids content was determined. The results indicate that E. anchoita is a valuable protein source and lipid with important content of n-3 polyunsaturated fatty acids. The developed quality index method scheme was composed of 28 demerit points, divided into 4 parameters and 10 attributes. All attributes showed correlation with time of storage (R > 0.90). The quality index (QI) presented a linear relationship with storage (QI = 2.55x days in ice + 1.76; R²= 0.98). In the shelf-life assessment-based quality index method, the rejection sensory point was observed after 7 days of storage due to the presence of unpleasant odours and deteriorated appearance. The total volatile basic nitrogen value remained below the upper limit of acceptability during the 10 days of ice storage. The evolution of thiobarbituric acid-reactive substances indicates lipids oxidation during the storage of anchovies. According to the results, the quality index method scheme developed for the E. anchoita stored in ice could be considered adequate to evaluate their freshness and to estimate its shelf-life.

SummaryThe aim of the present work was to investigate the physicochemical, biochemical and functional characteristics of both the myofibrils (MF) and actomyosin (AM) of squid mantle (Illex argentinus) and weakfish (Cynoscion guatucupa) muscles, and evaluate the influence of the addition of myofibrilar proteins from the squid mantle on the physicochemical and functional properties of those of the weakfish. After extraction, purification and characterization of the MF and AM of both species, emulsions of each protein fraction from each muscle were formulated. Mixtures of the MF or AM of both species were also analyzed. The emulsifying properties were monitoring using the Emulsifying Activity Index (EAI) and Emulsion Stability (ES). In addition, gel pastes were formulated from the squid mantle, weakfish muscle and the mixture of both species, and the following functional properties of the gels assessed: water holding capacity, colour, textural profile analysis (TPA) (hardness, elasticity, cohesiveness, gumminess) and gel strength. The EAI values of emulsions formulated with the MF of the mantle were significantly (p<0.05) higher than those formulated from those of weakfish. The incorporation of squid MF in the mixture increased the EAI values. Conversely, the highest ES values were obtained with weakfish MF, and the incorporation of MF weakfish in the mixture increased the ES values. Similar EAI and ES behaviours were observed for the AM of the corresponding species. Irrespective of the thermal treatment, the gel strength of the gelled paste of squid muscle was significantly (p<0.05) lower than that of weakfish muscle and of those obtained with the different mixtures. The behaviours of the expressible moisture (EM) from the gelled pastes were similar to those of gel strength. Irrespective of the thermal treatment, the pastes formulated with a high weakfish: mantle ratio showed less water loss. The gelled pastes of squid mantle showed the highest values for whiteness (WI) and the incorporation of squid muscle protein improved the WI of the mixtures. Campinas, v. 17, n. 1, p. 8-18, jan./mar. 2014 DOI: http://dx.doi.org/10.1590/bjft.2014 Resumo O objetivo do presente trabalho foi investigar as características físico-químicas, bioquímicas e funcionais de miofibrilas (MF) e actomiosina (AM) provenientes do músculo do manto de lula (Illex argentinus) e da pescada (Cynoscion guatucupa) e avaliar a influência da adição de proteínas miofibrilares do manto de lula sobre as propriedades físico-químicas e funcionais da pescada. Depois da extração, purificação e caracterização das MF e AM de ambas as espécies, foram formuladas emulsões de cada fração de proteína para cada um dos músculos. Também foi analisada a mistura de MF ou AM de ambas as espécies. Foram monitoradas as propriedades emulsificantes a partir do índice da atividade de emulsificação (IAE) e da estabilidade da emulsão (EE). Além disso, foram formuladas pastas de gel a partir do manto de lula, do músculo de pescada e da mistura de ambas as espécies e foram avali...

The characteristics of the thermal gelation of squid mantle paste and the effect of protease inhibitors on them were investigated. Pastes in the absence and presence the protease inhibitors, ethylendiaminetetracetic acid (EDTA) and phenylmethylsulfonyl fluoride (PMSF), were formulated. Pastes were made by the respective one or two step thermal treatments: direct heating at 85°C for 20 min and preincubation at 27 or 40 °C for 3 or 2 hours, followed by heating at 85 °C for 20 min. The gel strength, water holding capacity (WHC) and whiteness of gelled pastes were analyzed. The tricloroacetic acid (TCA) soluble peptides in homogenate of the muscle were determined. Gel strength decreased when heating was made in two steps. EDTA and PMSF were effective in avoiding that decrease when pre-incubation was made at 40 °C. Maximum gel strength was observed for the gels in presence of EDTA, giving values of 255 and 219 g x cm for the samples made by direct heating and pre-incubated at 40 °C  respectively. TCA soluble peptides increased between 20 and 60 °C, with maximum values reached at 30 and 60 °C. No significant differences (p>0.05) were observed in gel whiteness, neither with the thermal treatment nor with the inhibitors. The WHC was higher (p<0.05) in the gelated paste formulated with EDTA. These results show a good gelation capacity of I argentinus pastes and improvements with protease inhibitors.

The characteristics of the thermal gelation of squid mantle paste and the effect of protease inhibitors on them were investigated. Pastes in the absence and presence the protease inhibitors, ethylendiaminetetracetic acid (EDTA) and phenylmethylsulfonyl fluoride (PMSF), were formulated. Pastes were made by the respective one or two step thermal treatments: direct heating at 85 o C for 20 min and preincubation at 27 or 40 o C for 3 or 2 hours, followed by heating at 85 o C for 20 min. The gel strength, water holding capacity (WHC) and whiteness of gelled pastes were analyzed. The tricloroacetic acid (TCA) soluble peptides in homogenate of the muscle were determined. Gel strength decreased when heating was made in two steps. EDTA and PMSF were effective in avoiding that decrease when preincubation was made at 40 o C. Maximum gel strength was observed for the gels in presence of EDTA, giving values of 255 and 219 g x cm for the samples made by direct heating and pre-incubated at 40 o C respectively. TCA soluble peptides increased between 20 and 60 o C, with maximum values reached at 30 and 60 o C. No significant differences (p>0.05) were observed in gel whiteness, neither with the thermal treatment nor with the inhibitors. The WHC was higher (p<0.05) in the gelated paste formulated with EDTA. These results show a good gelation capacity of I. argentinus pastes and improvements with protease inhibitors.