Abstract This research aims to determine the efficiency of chitosan and xanthan gum films in conservation of croaker fillets kept in refrigeration for 9 days. Proximal composition, loss of mass, color, pH, TVB-N (Total Volatile Bases) and microbiological profile were assessed. The films were prepared with chitosan and xanthan gum in varying mass proportions 100:0, m:m (C100XG0); 60:40, m:m (C60XG40); 50:50, m:m (C50XG50). They presented the respective values for moisture content, water solubility, thickness and water vapor permeability: 24.59%, 19.50%, 0.086 mm and 11.45gm-1.s-1.Pa-1for C100XG0; 24.58%; 20.27%, 0.091 mm and 10.41 gm-1.s-1.Pa-1for C60XG40; 22.11%, 22.06%, 0.089 mm and 10.68 gm-1.s-1.Pa-1 forC50XG50.The films were made in small bags format capable to hold about 20 g of fish fillets. A control sample was prepared in parallel, using polyethylene bags under the same storage conditions. The results showed that the chitosan films combined with xanthan gum had excellent antimicrobial properties, capable of preserving the quality of chilled fish fillets during the studied period, since it inhibited the growth of Staphylococcus coagulase-positive, Salmonella spp and coliforms at 45 ° C. Mass loss of the croaker fillets was not significantly affected by xanthan gum addition to the films. On the other hand, xanthan gum addition affected pH and color parameters of the corvina fillets. It was also verified that the combination of these two polymers promoted the reduction of N-BVT, being the C50XG50 film that presented the best response.

Resumo A cor da superfície da carne é a primeira sensação que o consumidor percebe e utiliza como uma ferramenta para aceitar ou rejeitar um alimento. A medição e a avaliação da cor da carne podem também ser feitas por um indicador químico (metamioglobina) ou pela avaliação física, utilizando espaços da cor (a* e R). O objetivo deste trabalho foi avaliar a cor e a estabilidade da cor em filés de burriquete (Pogonias cromis) utilizando parâmetros de a* e R, e porcentagem de metamioglobina. Avaliaram-se a cor e a estabilidade da cor em filés de burriquete armazenados a 5 ± 1 °C com 90% de umidade relativa, durante 57,6 h, utilizando um sistema de visão computacional. Os parâmetros de vermelho (valor a* e R) variaram de forma inversa com a concentração de metamioglobina. A cinética foi plotada utilizando o modelo cinético, sendo que as ordens de reação para o valor a*, R e metamioglobina foram de 2,0309; 1,2101 e 1,8324, respectivamente; a constante de reação foi de -0,000046 para o valor a*, de -0,0013 para R e de 0,0002 para a metamioglobina. O sistema de visão computacional se apresenta como uma interessante ferramenta para avaliar a cor e a estabilidade da cor na carne de pescado, mas também pode ser utilizado em outro tipo de produtos alimentícios.

Abstract The colour of the meat surface is the first feeling that the consumer perceives and uses as a tool to accept or reject the food. The measurement and evaluation of meat colour can be measured by a chemical indicator (metmyoglobin) or by a physical assessment using colour spaces (a* and R). The objective of this study was to evaluate the colour and colour stability in burriquete (Pogonias cromis) fillets using the red parameters (a* value and R) and chemical analysis (% of metmyoglobin). The colour and colour stability of burriquete fillets stored at 5 ± 1 °C with 90% of relative humidity for 57.6 h was evaluated using a computer vision system. The red parameters (a* value and R) varied inversely with the metmyoglobin concentration. The kinetics were plotted using the kinetic model. The reaction orders for the a* value, R and metmyoglobin were 2.0309, 1.2101 and 1.8324, respectively and the reaction constants were -0.000046 for the a* value, -0.0013 for R and 0.0002 for metmyoglobin. The computer vision system was shown to be a powerful tool for assessing the colour and colour stability in fish meat but could also be used in other types of food product.

Abstract Hydrophilic polymers can form hydrogels, which are able to absorb and retain as much water as one hundred times their weight. Polymers based on natural products have been drawing attention since they are biocompatible, biodegradable and nontoxic. The aims of this study were to produce and to characterize a biopolymer with superabsorbent properties from fish protein isolates. Hydrogels were produced from protein isolates from Whitemouth croaker processing wastes chemically modified. The extension of change in lysine residues, kinetics in water-uptake capacity, pH effect, ionic strength over the absorption of water by hydrogels and the behavior of the biopolymer when subject to successive hydration and dehydrations were investigated. Results showed that acid modified protein without ethanol treatment reached a maximum absorption of 103.25 gwater/gdry gel, while the same sample modified with ethanol reached 216.05 gwater/gdry gel.

Abstract The aim of this study was to evaluate the properties of nanocomposite films of protein isolates from mechanically deboned chicken meat with organoclay (montmorillonite). For the film development, a 23 experimental design was performed with three levels, protein isolate (2, 3.5, 5 g.100 mL-1 of solution), montmorillonite (0.3, 0.5, 0.7 g.100mL-1 of solution) and glycerol (25, 30, 35 g.100 mL-1 CPI). The tensile strength varied between 6.7 and 9.1 MPa, elongation to break from 26-66%, opacity of 13.1 to 35.7 and solubility from 38.5% to 81.8%. Assessing the structural properties, interleaving of the isolate and montmorillonite can be noted. The results obtained in the experimental design indicate that 2.0 g of CPI.100 g-1 of solution, 0.8 g of MMT.100 g-1of solution and 0.2 g of glicerol.100 g-1CPI are the ideal parameters for preparing nanocomposite films.

A significant amount of insoluble fibrous protein, in the form of feather, hair, scales, skin and others are available as co-products of agro industrial processing. These wastes are rich in keratin and collagen. This study evaluated different fungi for the hydrolysis of insoluble fish protein residues. Proteins resulting from Micropogonias furnieri wastes through pH-shifting process were dried and milled for fermentation for 96 h. This resulted the production of keratinolytic enzymes in the medium. Trichoderma sp. on alkaline substrate (28.99 U mL-1) and Penicillium sp. on acidic substrate (31.20 U mL-1) showed the highest proteolytic activities. Penicillium sp. showed the largest free amino acid solubilization (0.146 mg mL-1) and Fusarium sp. the highest protein solubilization (6.17 mg mL-1).

Gelatin was extracted from the skin of tilapia (Oreochromis urolepis hornorum) and characterized according to its physical and chemical properties. It had pH 4.66, which is slightly higher than the values reported for gelatins processed by acid solubilization. In general, the ionic content was low, and the average yield of the process was 5.10 g/100 g. The proximal composition of the gelatin was similar to that of the commercial gelatins, with slightly higher moisture content. The tilapia skin gelatin had whitish-yellow color and average turbidity of 67 NTU.

O interesse pela produção de óleo de pescado para consumo humano é crescente. No Alasca, EUA, uma grande quantidade de subprodutos tem sido usada como matéria-prima. Entre os subprodutos, o fígado de Alaska pollock (Theragra chalcogramma) apresenta interesse particular em razão de seu alto teor de lipídios. Normalmente, a temperatura usada para extração do óleo de pescado é elevada e potencialmente incompatível com a estabilidade lipídica. O objetivo deste trabalho foi avaliar o processamento do óleo de fígado de Alaska pollock, extraído a baixas temperaturas. Como confirmado, a matéria-prima obtida na primavera (40%) apresentou um conteúdo lipídico menor que a de outono (50%). A extração foi realizada cinco vezes para quatro combinações de tempo (15 e 30 minutos) e temperatura (50 e 60 ºC). Foram analisadas duas bateladas de óleo de fígado e vísceras de pollock, produzido em navio processador. O rendimento do processo foi semelhante (aproximadamente 52%), os óleos de fígado produzidos se apresentaram mais claros, com coloração amarela, comparados aos de vísceras de pollock produzidos no outono. Os ácidos graxos livres foram similares para óleos de fígado e de vísceras nas duas estações, atingindo, no máximo, 0,4%; o índice de peróxidos, o valor de anisidina e o valor de ácido tiobarbitúrico determinados nos óleos apresentaram 2-14 meq.kg-1, 20-26 e 0,4-0,6 mg dialdeído malônico.kg-1, respectivamente. Todos os óleos investigados foram compostos principalmente por triacilgliceróis (88-100%), com o conteúdo de fósforo não excedendo, em média, 15 ppm.

The demand for edible fish oils is growing. In Alaska, USA, large quantities of fishery byproducts are being used as raw materials, amongst which, Alaska pollock (Theragra chalcogramma) livers are of particular interest due to their high lipid contents. The temperature normally used for the extraction of fish oils is high and potentially incompatible with lipid stability. The goal of this research was to evaluate the processing of Alaska pollock liver oil, processed at low temperatures. As expected, the raw material obtained in the spring (40%) had significantly less lipids than that obtained in the autumn (50%). The liver oils were rendered five times for each of four combinations of time (15 and 30 minutes) and temperature (50 and 60 ºC). Two batches of liver and viscera pollock oils produced on a processing ship were analyzed. The process yields were similar (~52%), and in general, the liver oils produced were lighter and more yellowish in colour than those produced from the pollock viscera in the autumn. The free fatty acid levels were similar for the viscera and liver oils produced in both seasons, reaching a maximum of 0.4%, while the peroxide values, anisidine values and thiobarbituric acid values determined for all the oils were 2-14 meq.kg-1, 20-26 and 0.4-0.6 mg malonic dialdehyde.kg-1, respectively. All the oils investigated were composed mainly of triacylglycerols (88-100%), with the phosphorus content not exceeding, on average, 15 ppm.

O objetivo deste trabalho foi avaliar as propriedades de biofilmes nanocompósitos de isolado proteico de corvina (Micropogonias furnieri) com argila organofílica. Inicialmente, foi obtido isolado proteico de corvina (IPC) utilizando-se o processo de mudança de pH. O IPC foi obtido a partir de subprodutos da industrialização de corvina. Para o desenvolvimento dos filmes, foi executado um planejamento experimental de Box e Behnken, com três níveis de IPC (2; 3,5; 5 g.100 g-1 de solução), argila montmorilonita MMT (0,3; 0,5; 0,7 g.100 g-1 de solução) e glicerol (25, 30, 35 g.100 g-1 IPC). Os filmes poliméricos foram desenvolvidos pela técnica de casting. Os valores de resistência à tração variaram entre 7,2 e 10,7 MPa, e os valores de alongamento, de 39,6 a 45,8%. Os valores de permeabilidade ao vapor de água (PVA) variaram entre 3,2 e 5,5 g mm m-2 d-1kPa-1. O IPC apresentou teor médio de proteína de 97,87% (b. s.). Pode-se concluir que os filmes nanocompósitos produzidos a partir de IPC com MMT foram promissores, desde o ponto de vista das propriedades mecânicas, da aparência visual e do fácil manuseio até a baixa permeabilidade ao vapor de água e a baixa solubilidade. Com relação às propriedades mecânicas, as concentrações de IPC e MMT foram os principais fatores que influenciaram o desenvolvimento dos filmes nanocompósitos. Os resultados obtidos no planejamento experimental utilizado indicaram que 3,5 g de IPC.100 g-1 de solução, 0,5 g de MMT.100 g-1 de solução e 30 g de glicerol.100 g-1 IPC seriam os parâmetros ideais para a preparação de filmes nanocompósitos por casting.

The objective of this study was to evaluate the properties of nanocomposite biofilms based on Whitemouth croaker (Micropogonias furnieri) protein isolate with organophilic clays. Initially the croaker protein isolate (CPI) was obtained using the pH shifting process from by-products of croaker industrialization. A Box and Behnken experimental design was used to develop the films, with three levels of CPI (2, 3.5 and 5 g.100 g-1 solution), montmorilonite MMT clay (0.3, 0.5 and 0.7 g.100 g-1 solution) and glycerol (25, 30 and 35 g.100g-1 CPI). The polymeric films were produced by the "casting" technique. The tensile strength values ranged from 7.2 to 10.7 MPa and the elongation values from 39.6 to 45.8%. The water vapor permeability (WVP) values ranged from 3.2 to 5.5 (g.mm.m-2.d-1.kPa-1) and the CPI had an average protein content of 97.87% protein (d. b.). It was concluded that the nanocomposite films produced from CPI with MMT were promising from the standpoint of their mechanical properties, visual appearance and easy handling, as well as for their low water vapor permeability and low water solubility. With respect to their mechanical properties, the concentrations of CPI and MMT were the main factors influencing the development of the nanocomposite films. The results obtained from the experimental design indicated that 3.5 g of CPI.100 g-1 solution, 0.5 g of MMT.100 g-1 solution and 30 g of glycerol.100 g-1 CPI would be the ideal parameters for the development of nanocomposite films by "casting".

A diversificação da oferta de produtos pesqueiros e, as práticas de aquicultura poderão incrementar o consumo destes produtos, desde que a exigência cada vez maior dos consumidores por alimentos de melhor qualidade, frescos e naturais, seja levada em consideração. O objetivo deste trabalho foi desenvolver um estudo tecnológico visando à obtenção de um alimento minimamente processado à base de carpa-capim (Ctenopharyngodon idella), estudando os fatores que influenciam na qualidade dos filés de carpa sob embalagem com atmosfera modificada a vácuo, armazenadas a temperatura de refrigeração. Em resumo, o processamento mínimo aplicado às amostras, aliado à embalagem a vácuo permitiu aumentar a vida-útil dos filés de carpa-capim.

The offer of fishery products and the Aquaculture practices will can increase consume if the exigency for fresh and high quality products would be attend. The objective of this work was obtain a MPR product with grass carp (Ctenopharyngodon idella), studying the factors that was important in the quality and in the deterioration of the products with modified atmosphere packaging at vacuum, stored at refrigeration temperature. In short, the MPR practices applied in the products and the vacuum packaging, allowed to increase the storage time of the grass carp fillets.