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".

O objetivo desta revisão é abordar as aplicações de nanotecnologia em alimentos, enfatizando o uso de nanopartículas lipídicas sólidas, nanoemulsões, nanocápsulas e de nanocompósitos para embalagens de alimentos, bem como os métodos de obtenção, a funcionalidade e as suas características. A aplicação da nanotecnologia em alimentos é nova em comparação com a área biomédica e as indústrias de tecnologia de informação, nas quais a nanotecnologia já é utilizada na fabricação de materiais. No entanto, já existem inúmeras oportunidades que podem ser exploradas, como a elaboração de produtos com características funcionais e nutracêuticas, o desenvolvimento de processos e as embalagens inteligentes. Esta revisão aborda os seguintes itens: nanopartículas lipídicas sólidas, nanoemulsões, nanocápsulas, nanocompósitos em embalagem e os riscos e a legislação para a nanotecnologia. Nanopartículas lipídicas sólidas são sistemas de transporte coloidal empregados para encapsular, proteger e entregar componentes funcionais. Nanoemulsão consiste em uma dispersão muito fina composta por uma fase de óleo e uma fase aquosa, com tamanho de gota, em escala nanométrica; em função do seu tamanho característico, as nanoemulsões são transparentes ou translúcidas, e possuem estabilidade contra a sedimentação. Nanocápsulas são compostas por um invólucro polimérico disposto ao redor de um núcleo, no qual se encontra o composto ativo, conferindo proteção contra o oxigênio, a água e/ou a luz; permitem, dessa forma, uma liberação controlada da substância e/ou previnem o contato com outros componentes em uma mistura. Em nanotecnologia de embalagens, aborda-se a utilização de nanopartículas, tais como nanofibras de celulose e nanoargila, bem como a aplicação de nanomateriais com propriedades nutricionais e/ou antimicrobianas, e nanosensores. Serão abordados também aspectos relacionados aos riscos e à legislação em nanotecnologia de alimentos.

The objective of this review was to study the applications of nanotechnology in foods, emphasizing the use of solid lipid nanoparticles, nanoemulsions, nanocapsules and nanocomposites for food packaging and also review the production methods, functionality and characteristics. Nanotechnology in foods is new as compared to the biomedical area and information technology industries, where nanotechnology has been used in the manufacture of materials. However, there are many opportunities that can be explored, such as the development of products with functional and nutraceutical characteristics, process development and intelligent packaging. In this review, solid lipid nanoparticles, nanoemulsions, nanocapsules and nanocomposites for use in packaging, will be examined, as also the risks and legislation regarding nanotechnology. Solid lipid nanoparticles are colloidal transport systems developed to encapsulate, protect and deliver functional components. Nanoemulsions are a very fine dispersion consisting of an oil phase and an aqueous phase with a droplet size on a nanometric scale. Due to their characteristic size, these emulsions are transparent or translucent and present stability against sedimentation. Nanocapsules are composed of an active central core surrounded by a thin polymeric wall, providing protection of the active compound against oxygen, water and/or light, allowing for a controlled release of the substance and/or preventing contact with other components in a mixture. The use of nanoparticles such as cellulose nanofibres and nanoclays in packaging nanotechnology will be discussed; and also the application of nanomaterials with nutritional and/or antimicrobial properties; and the application of nanosensors. Issues related to the legislation and risks of food nanotechnology will also be discussed.

O objetivo deste trabalho foi estudar as propriedades físicas, mecânicas e de barreira dos filmes produzidos a partir de diferentes concentrações de proteínas miofibrilares de pescado de baixo valor comercial. O pescado utilizado foi a corvina (Micropogonias furnieri), que foi eviscerada e filetada. As proteínas miofibrilares foram obtidas do músculo, em sucessivas lavagens com água destilada. Os filmes foram produzidos com 3, 4 e 5% de proteínas miofibrilares pelo método de casting. Os filmes foram analisados nos seguintes aspectos: espessura, solubilidade, opacidade, resistência à tração, elongação e permeabilidade ao vapor de água (PVA). O aumento da concentração de proteínas miofibrilares atribuiu aos filmes maior espessura, opacidade, resistência à tração e PVA; no entanto, conferiu menor elongação na ruptura dos mesmos.

The objective of this work was to study the physical, mechanical and barrier properties of the films produced from different concentrations of myofibrillar proteins of fish. The fish used was croaker (Micropogonias furnieri), which was gutted and filleted. The myofibrillar proteins were obtained through the muscle with successive washes with distilled water. The films were made with 3, 4 and 5% of myofibrillar proteins by the method of casting. The films were analyzed by thickness, solubility, opacity, tensile strength, elongation and water vapor permeability (PVA). The increase of myofibrillar proteins concentration in the films increased thickness, opacity, tensile strength and water vapor permeability and reduced elongation at break of the film.

A presença de microrganismos em produtos alimentícios durante produção, armazenamento, transporte e embalagem é inevitável. Sendo assim, conhecer o comportamento do crescimento microbiano é muito importante para a segurança alimentar e estimativa da vida útil. Neste trabalho foi simulada a cadeia de abastecimento de peitos de frangos cru, salgado e cozido durante 20 dias a -18 ± 0,5 ºC (simulação da expedição industrial no Brasil e transporte por navio até a Europa) e, após o descongelamento, 21 dias a 4 ± 0,5 ºC (simulação da vida útil em supermercado). Os produtos foram analisados quanto a Pseudomonas spp., Salmonella spp., Listeria monocytogenes, Staphylococcus spp. e microrganismos viáveis totais (mesófilos e psicrotróficos). As análises de contagem em placas foram seguidas por testes bioquímicos clássicos para a confirmação de colônias típicas. Em nenhuma das amostras foi detectada a presença de Salmonella spp. ou de Listeria monocytogenes. Em termos de contagem de colônias viáveis totais, durante os primeiros 20 dias (a -18 ºC) a presença de microrganismos se manteve estável em baixos níveis de detecção. Depois do descongelamento, curvas de crescimento microbiano foram observadas. De acordo com os parâmetros microbiológicos de segurança, tempos entre 9 e 11 dias a 4 ºC mostraram-se como os limites para garantir a qualidade destes produtos

The presence of the microbial organisms in food products during the production, storage, transport, and packaging is unavoidable. Therefore, the knowledge of the microbial growth behavior is very important for the food safety and shelf life assessment. In this work, a chicken supply chain was simulated for raw, salted, and cooked chicken breasts for 20 days at -18 ± 0.5 ºC (simulation of industry expedition in Brazil and transport by ship to Europe) and for defrosted chicken breasts for 21 days at 4 ± 0.5 ºC (simulation of the shelf life in supermarket). The products were analyzed for Pseudomonas spp., Salmonella spp., Lysteria monocytogenes, Staphylococcus spp. and total viable counts (mesophilic and psicrotrophic microorganisms). The counting plate analyses were followed by classical biochemical tests for typical colonies confirmation. None of the samples was positive for Salmonella spp. and Lysteria monocytogenes. In terms of total viable colonies counting, during the first 20 days (-18 ºC), the presence of microorganisms was kept stable at low levels of detection. After defrosting, microbial growth curves were observed. According to the safety parameters, 9 to 11 days at 4 ºC proved the best time limit to guarantee the quality of those products

The objective of this study was to obtain and evaluate physicochemical and functional properties of protein concentrates from Micropogonias furnieri produced by pH shifting process, using alkaline and acid solubilization followed by isoelectric precipitation of muscle proteins. The concentrates showed high protein content and the maxim solubility for the minced (96.5%), for the alkaline (97.5%) and acid (93.7%) extraction was obtained at pH 11.0. The water holding capacity of the alkaline concentrate resulted in a value same or superior to water holding capacity of the acid concentrate in all investigated values of pH. The oil holding capacity of alkaline and acid concentrates showed no significant difference between the studied processes.

The objective of this work was to obtain hydrolysates with different degrees of hydrolysis using Alcalase 2.4L® and to evaluate the effect of the enzyme [E] and substrate [S] concentration on the functional properties of the hydrolysates. It was obtained hydrolysates with hydrolysis degree values ranging from 12.2 to 43.7%. The values of solubility and water holding capacity were similar for the greater number of the hydrolysates with minimum values in the pH 5.0. The hydrolysis degree showed direct relationship with the solubility and indirect with the water holding capacity, oil holding capacity, emulsifying capacity and foaming capacity.

The objective of this work was to study the influence of enzymes Alcalase, Flavourzyme and Novozym in the functional properties of hydrolysates of Bluewing searobin (Prionotus punctatus) minced. The hydrolysates of Bluewing searobin were evaluated for the chemical composition and the functional properties. The Novozym enzyme presented greater specific activity differing significantly from the enzymes Alcalase and Flavourzyme. The hydrolysates of Bluewing searobin presented protein content above of 87% and excellent solubility, capacity of water retention, capacity of oil retention and emulsifying capacity.

The enzymatic modification of proteins has been widely studied with the aim of add value to low commercial value fish. The objective of this work was to evaluate and optimize the parameters involved in the production process of an enzymatic protein hydrolyzed with high protein content. The results showed that for Alcalase the most significant parameters were temperature, pH and substrate concentration and for Flavourzyme were pH, substrate concentration and enzyme concentration. It was obtained for Alcalase a predictive model for the recovered nitrogen and for Flavourzyme a predictive model for the hydrolysis degree.