EQA - Escola de Química e Alimentos
URI permanente desta comunidadehttps://rihomolog.furg.br/handle/1/1610
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46 resultados
Resultados da Pesquisa
- ItemCongelamento e descongelamento – sua influência sobre os alimentos(EDGRAF, 2003) Colla, Luciane Maria; Prentice-Hernández, CarlosNo congelamento, três etapas principais merecem a atenção do profissional em alimentos: o congelamento propriamente dito, a estocagem e o descongelamento. O congelamento consiste na redução da temperatura sem promover mudança de fase e cristalização, que compreende a nucleação e o crescimento dos cristais. A velocidade de congelamento influencia tanto a localização quanto o tamanho e a quantidade dos cristais de gelo formados. Em altas taxas de congelamento, ocorre a formação de pequenos cristais de gelo e em grande quantidade, com mínimo deslocamento de água, sendo que a aparência do produto congelado, após o descongelamento, é similar ao produto não congelado. Em condições de congelamento lento, os cristais formados são maiores e em menor quantidade, ocasionando a ruptura das células, a injúria celular por força do aumento da pressão osmótica e a precipitação irreversível ou a desnaturação dos constituintes coloidais da célula. Esse fato traz, em conseqüência, forte exsudação no descongelamento, com perda de nutrientes, principalmente no meio intracelular. Portanto, o descongelamento deve ser realizado de forma gradual e lenta, sob temperatura de refrigeração, diminuindo-se assim a quantidade de líquido exsudado. O congelamento como técnica de conservação de alimentos é eficiente desde que sejam observados alguns cuidados como altas taxas de congelamento, pequena variação da temperatura nas câmaras de estocagem e descongelamento lento, preferencialmente sob refrigeração, evitando assim a recontaminação dos produtos por microrganismos.
- ItemFractionation of protein hydrolysates of fish and chicken using membrane ultrafiltration: investigation of antioxidant activity(Springer, 2014) Centenaro, Graciela Salete; Salas-Mellado, Myriam de las Mercedes; Pires, Carla; Batista, Irineu; Nunes, Maria; Prentice-Hernández, CarlosIn this work, chicken and fish peptides were obtained using the proteolytic enzymes α-Chymotrypsin and Flavourzyme. The muscle was hydrolyzed for 4 h, and the resulting peptides were evaluated. Hydrolysates were produced from Argentine croaker (Umbrina canosai) with a degree of hydrolysis (DH) of 25.9 and 27.6 % and from chicken (Gallus domesticus) with DH of 17.8 and 20.6 % for Flavourzyme and α-Chymotrypsin, respectively. Membrane ultrafiltration was used to separate fish and chicken hydrolysates from Flavourzyme and α-Chymotrypsin based on molecular weight cutoff of >1,000, <1,000 and >500, and <500 Da, to produce fractions (F1,000, F1,000–500, and F500) with antioxidant activity. Fish hydrolysates produced with Flavourzyme (FHF) and α-Chymotrypsin showed 60.8 and 50.9 % of peptides with a molecular weight of <3 kDa in its composition, respectively. To chicken hydrolysates produced with Flavourzyme and α-Chymotrypsin (CHC) was observed 83 and 92.4 % of peptides with a molecular weight of <3 kDa. The fraction that showed, in general, higher antioxidant potential was F1,000 from FHF. When added 40 mg/mL of FHF and CHC, 93 and 80 % of lipid oxidation in ground beef homogenates was inhibited, respectively. The composition of amino acids indicated higher amino acids hydrophobic content and amino acids containing sulfuric residues for FHF, which showed antioxidant potential.
- ItemPhysical, mechanical and antimicrobial properties of Argentine anchovy (Engraulis anchoita) protein films incorporated with organic acids(Elsevier, 2014) Rocha, Meritaine da; Loiko, Márcia Regina; Tondo, Eduardo César; Prentice-Hernández, CarlosPhysical, mechanical and antimicrobial properties of protein films from Argentine anchovy (Engraulis anchoita) incorporated with 0, 0.50, 0.75 and 1.50% sorbic or benzoic acids were investigated against Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Enteritidis and Staphylococcus aureus. The effects of films containing 1.50% sorbic or benzoic acids were tested on meat inoculated with Escherichia coli O157:H7 and Listeria monocytogenes during storage at 5 C. The increased concentration from 0.50 to 1.50% of sorbic and benzoic acids resulted in decreased tensile strength and increased elongation at break, color difference, opacity, water vapor permeability and solubility. Scanning electron microscopic images of the control film revealed a homogeneous and continuous structure and the presence of micropores on the film surface containing 1.50% of sorbic or benzoic acids, which contributed to the physical and mechanical properties of the resulting films. The control films did not inhibit many microorganisms tested in this study. Films with 1.50% sorbic or benzoic acids had the highest inhibition against Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes, however they did not inhibit Staphylococcus aureus. Films with 1.50% sorbic or benzoic acids applied in meat showed the greatest inhibition of Listeria monocytogenes and Escherichia coli O157:H7. These results suggest that the films containing antimicrobials can be used to promote safety and quality of packaged meat, though the physical and mechanical properties of the films could be modified.
- ItemUse of smart photochromic indicator for dynamic monitoring of the shelf life of chilled chicken based products(Elsevier, 2014) Brizio, Ana Paula Dutra Resem; Prentice-Hernández, CarlosThis study evaluated the applicability of a photochromic time temperature indicator (TTI) to monitor the time– temperature history and shelf life of chilled boneless chicken breast. The results showed that the smart indicator showed good reproducibility during the discoloring process in all the conditions investigated. The response was not only visibly interpretable but also well adaptable to measurement using appropriate equipment. For an activation configuration of 4 s of ultraviolet light (UV) per label, the TTI's rate of discolorationwas similar to the quality loss of themeat samples analyzed. Thus, the photochromic label (4 s UV/label) attached to the samples set out to be a dynamic shelf-life label, assuring consumers the final point of quality of chilled boneless chicken breast in an easy and precise form, providing a reliable tool to monitor the supply chain of this product.
- ItemUsing edible coatings fromWhitemouth croaker (Micropogonias furnieri) protein isolate and organo-clay nanocomposite for improve the conservation properties of fresh-cut ‘Formosa’ papaya(Elsevier, 2014) Cortez-Vega, William Renzo; Pizato, Sandriane; Souza, Juliana Tais Andreghetto de; Prentice-Hernández, CarlosEdible coatings have been used in the fresh-cut industry as a strategy to reduce the deleterious effects of minimal processing on plant tissues. The objective of this study was to apply edible coatings from protein isolate of Whitemouth croaker with organo-clay montmorillonite in minimally processed papaya slices, throughout the storage of 12 days at 5 °C, and assess their properties and verify the effectiveness of this coating as a barrier against theweight loss of papaya, aiming to increase its shelf-life. The different coatings appliedwith andwithout montmorillonite in minimally processed papaya were effective during the 12 days of storage. The croaker protein isolate (CPI) and montmorillonite (MMT) coating applied to minimally processed papaya showed lower mass loss (5.26%), lower microbial growth and a smaller decrease of firmness, lightness and pH, and therefore showed the best results in coating of minimally processed papaya. Industrial relevance: Papaya is verymuch appreciated in its minimally processed, but this type of processing causes injuries so that its shelf-life is reduced. This perishability of papaya needs a good preservation strategy. The present results demonstrated the feasibility of using edible coatings on the basis of fish protein isolate and organo-clay nanocomposite, with low cost and high shelf-life compared to the control sample. The study further confirms that the viability of fish protein of low value for the industries becomes a great potential to increase the shelflife of minimally processed papaya, without changing the characteristics in relation to odor and appearance of minimally processed fruit.
- ItemImprovement Quality and Shelf Life Assessment of Minimally Processed Apples by Use of Protein Coatings(Canadian Center of Science and Education, 2013) Pizato, Sandriane; Cortez-Vega, William Renzo; Costa, Tailine Saturnino da; Oliveira, Lauren Menegon de; Prentice-Hernández, CarlosMinimally processed fruits offer a convenient and practical product to the consumer, with quality and freshness similar to the in natura product. The aim of this study was to apply coatings of croaker protein isolate (Micropogonias furnieri) with organoclay (montmorillonite) on minimally processed apples during 12 days of storage at 5 ± 1 °C. The apples were washed, peeled and cut into cubes. Coatings were then applied where T1 (control sample), T2 (croaker protein isolate coating) and T3 (croaker protein isolate coating and montmorillonite (MMT). The pieces were allowed to drain into sieves and these were stored in polyethylene terephthalete (PET) packaging for a period of 12 days at 5 ± 1 °C. Analyses of weight loss, firmness, color (Lightness (L*), Chroma a* and b*), pH, and microbiological analyses (psychrotrophic, yeasts and molds, Salmonella and Escherichia coli) were carried out. The analyses were carried out in triplicate and evaluated at the times of 1, 3, 5, 7, 9 and 12 days of storage. The use of croaker protein isolate coating and MMT proved promising in keeping weight loss, microbiological counts, enzymatic browning and firmness loss at minimum in minimally processed apples.
- ItemInfluence of chicken protein isolate and heating temperature on textural properties of low-fat frankfurters(2011) Brito, Kelly de Moraes; Salas-Mellado, Myriam de las Mercedes; Prentice-Hernández, Carlos; Rafael, RuanThe effects of chicken protein isolate (CPI) addition and heating temperature on the textural properties of low-fat frankfurters were investigated. Frankfurter quality was determined by measuring textural, color, and sensory characteristics. A high temperature caused an increased firmness, breaking force, and gel strength of the frankfurters, and CPI concentration intensified the gel strength. The commercial chicken frankfurters had a greater acceptability and purchase intention than the experimental frankfurters with CPI when evaluated by panelists. The frankfurters with CPI addition (without pork lard) had a lower fat content than the commercial chicken frankfurters. The total replacement of fat by CPI in the experimental frankfurters contributed to the production of a low-fat product because it had a 60% lower lipid content than the commercial chicken frankfurters while maintaining good textural characteristics.
- ItemRevisão: Características de nanopartículas e potenciais aplicações em alimentos(2012) Assis, Letícia Marques de; Zavareze, Elessandra da Rosa; Prentice-Hernández, Carlos; Soares, Leonor Almeida de SouzaO 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.
- ItemComparisons of the Properties of Whitemouth Croaker (Micropogonias furnieri) Surimi and Mechanically Deboned Chicken Meat Surimi-Like Material(2012) Cortez-Vega, William Renzo; Fonseca, Gustavo Graciano; Prentice-Hernández, CarlosThe aim of this work was to evaluate and compare the color, texture and sensory characteristics of whitemouth croaker (Micropogonias furnieri) surimi and mechanically separated chicken meat (MDCM) surimi-like material (SLM). The whiteness of the MDCM-SLM was higher (P > 0.05) than that from the surimi. Higher breaking force (P < 0.05) and gel strength (P < 0.05) were also observed for the MDCM-SLM when compared to the surimi. The deformation did not vary significantly for these two products (P > 0.05). The MDCM-SLM was more accepted by the panelists (P < 0.05). The mean scores of overall desirability for MDCM-SLM was similar to that observed for walleye Pollack surimi that is the parameter of quality. The differences in the acceptability of poultry and fish food products are probably due to peo-ples’ eating habits.
- ItemHydrolysis of Insoluble Fish Protein Residue from Whitemouth croaker (Micropogonias furnieri) by Fungi(2014) Martins, Vilásia Guimarães; Palezi, Simone Canabarro; Costa, Jorge Alberto Vieira; Prentice-Hernández, CarlosA 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).