Abstract Kafirins, water-insoluble proteins from Sweet Sorghum BR501 grains, have been an alternative to prepare edible coatings for food due to their hydrophobic character. In this work, the secondary structures (SS) content of reduced (SSr) and unreduced (SSu) kafirins were determined by 13C solid-state-NMR spectroscopy using areas of carbonyl peak. The SS elucidate by fitting the signal with the Lorentzian function shows 56% and 59% of α-helix and 40% and 12% of β-sheet structures for SSr and SSu, respectively. The SS also were elucidated by a Singular value decomposition- SVD method shows 55% and 49% of α-helix and 12% and 8% of β-sheet structure for SSr and SSu, respectively. Since SVD does not depend on the operator and has higher correlation coefficients for α-helix (0.96%) and β-sheet (0.91%), it is a reliable method to quantify the SS of insoluble proteins using the 13C NMR signal.

RESUMO: Durante a vida de prateleira da carne fresca podem ocorrer mudanças físico-químicas, microbiológicas e sensoriais indesejadas. Para evitar tais mudanças a combinação da embalagem tradicional à vácuo com revestimentos comestíveis é uma alternativa. O objetivo deste estudo foi avaliar o efeito do uso de diferentes revestimentos comestíveis à base de zeínas em combinação com diferentes óleos vegetais (óleos de: pimenta rosa, alecrim, azeite e combinação de azeite + óleo de pimenta rosa ou alecrim) nas características fisico-químicas da carne ovina, embalada à vácuo e armazenada à temperatura 5±1 °C. Foram realizadas análises de pH, cor instrumental, capacidade de retenção de água (CRA), força de cisalhamento, substâncias reativas ao ácido tiobarbitúrico (TBARS) a cada sete dias, no período de 29 dias. Foram observadas diferenças significativas (P<0,05) para o efeito de revestimentos e o tempo de armazenamento. A combinação de azeite mais óleo de pimenta (OLPP), apresentou maior estabilidade de cor, enquanto que os revestimentos contendo alecrim (RO), alecrim mais azeite (OLRO) e óleo de pimenta (PP) foram os que apresentaram maior estabilidade oxidativa no período de 29 dias. Os parâmetros pH, CRA e força de cisalhamento não parecem ter sido afetados pelos revestimentos. Tendo em vista que aparência é um importante fator de compra, o revestimento contendo azeite e óleo de pimenta rosa foi o mais promissor para ser utilizado na manutenção da qualidade de carne ovina.

ABSTRACT: During the shelf-life of fresh meat, physical, chemical, microbiological, and sensory changes may occur. To avoid such changes, the combination of vacuum-packaging and use of edible coatings make a good strategy. This study aimed to evaluate the physicochemical characteristics of vacuum-packaged lamb meat combined with different zein-based edible coatings containing different vegetable oils (pink pepper, rosemary, olive oil, and the combinations of olive oil + pink pepper or rosemary), stored at 5 ± 1 °C. Parameters including pH, instrumental color, water holding capacity (WHC), shear force, and thiobarbituric acid reactive substances (TBARS) were analyzed every seven days, for 29 days. Significant differences (P<0.05) were observed in coating effects and storage time. The combination of olive oil and pepper oil (OLPP) exhibited higher color stability, while the coatings containing rosemary (RO), rosemary and olive oil (OLRO), and pink pepper oil (PP) exhibited the highest oxidative stability in 29 days. The pH, WHC, and shear force parameters did not appear to have been affected by the coatings. In summary, as appearance is an important purchasing factor, the coating containing olive oil and pink pepper oil is very promising as an alternative for maintaining vacuum-packaged lamb meat quality.

Abstract Research is being conducted in an attempt to produce biodegradable packaging to replace plastic products, thereby reducing solid waste disposal. In this work, zein films were produced from vegetable oils (macadamia, olive and buriti) and from pure oleic acid. The surface of zein-based films made using oleic acid has a good lipid distribution. The high content of oleic acid produced a film with the greatest elongation at break (8.08 ± 2.71%) due to the greater homogeneity of the protein matrix. The different oils did not affect the glass transition temperature (Tg). Tg curves of films with fatty acids showed a reduction in mass at between 50 and 120 °C due to water evaporation. At 120 °C the weight loss was 3-5% and above this temperature further weight loss was observed with the highest loss being seen in the film made using pure oleic acid. In conclusion, although biodegradable films were produced using the four different oils, the film made from pure oleic acid has the best characteristics.

O objetivo do trabalho foi identificar as injúrias mecânicas que ocorrem em mamões 'Golden' e avaliar seus efeitos na qualidade dos frutos armazenados a 22ºC e 85% UR durante 10 dias. As injúrias identificadas como abrasão, corte e amassado foram reproduzidas nos frutos. As abrasões foram provocadas com lixa grão 200, numa área de 6cm². Os cortes foram realizados com incisões de 30 mm de comprimento e 5 mm de profundidade. O amassado foi provocado pelo impacto dos frutos, que foram deixados cair de uma altura de 2 m. Cada fruto recebeu 2 injúrias em lados opostos, na região de maior diâmetro. Mamões intactos foram utilizados como controle. A região danificada pela abrasão não desenvolveu cor amarelo-alaranjada; ocorreu escurecimento da casca, comprovado pelos menores valores de luminosidade e cromaticidade. Abrasão e impacto levaram a maior redução da firmeza da polpa e perda de massa. Imagens de ressonância magnética revelaram que frutos danificados pelas injúrias perderam sua integridade, o que foi identificado por áreas claras devido à presença de água livre. A qualidade de mamões 'Golden' é prejudicada por injúrias mecânicas, principalmente pelo impacto pela abrasão.

This work aimed to identify the mechanical injuries that occur in 'Golden' papaya fruits, and to evaluate the injuries effects on the quality of the fruits at early ripening stage and storage at 22ºC and 85% RH for 10 days. The mechanical injuries identified were abrasion, cuts and bruises. Abrasion was caused by 200 mesh sandpaper in a 6 cm² of peel surface area. Cut injury was obtained by cutting fruits at 30mm length and 5mm depth. Bruises were produced in the papayas by impact, which were dropped from 2 m height onto a hard surface. Each fruit were injured twice in the opposite sides at the widest diameter region. Intact fruits were considered as control. Injured areas by abrasion did not develop the typical yellow color. The luminosity and chroma values were lower in injured areas. Abrasion and impact injuries were responsible for flesh firmness decrease and higher water loss. Magnetic resonance images showed that injured papaya fruits lost their integrity. In the injured areas were visualized clear region due to free water content. The quality of 'Golden' papaya fruits is affect by mechanical injuries, mainly due to the impact and the abrasion injuries.