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Biopolymers, such as proteins and carbohydrates, can be used for the production of biofilms, as they are biodegradable, biocompatible, and capable of providing adequate technological characteristics for films. This study aimed to evaluate the influence of different concentrations of fish myofibrillar proteins and cassava starch on the rheological and technological properties of filmogenic solutions (FS) and films. FS were prepared with 1% protein (fish residue) (F1), 4% starch (F2), 0.5% protein + 2% starch (F3), 1% protein + 2% starch (F4), and 0.5% protein + 4% starch (F5) all with 30% glycerol. Rheological analyzes of apparent viscosity were performed on the filmogenic solutions and were evaluated the technological properties, thermogravimetric (TGA/DTG and DSC), x-ray diffraction, infrared spectroscopy (FTIR-ATR), microscopy (SEM), and spectroscopy (EDS) in elaborate films. The FS showed a non-Newtonian behavior (n ≠ 1), with dilating and pseudoplastic fluids for proteins and starch, respectively, both model Herschel-Bulkley. The color of the raw materials influenced the color of the films (p ≤ 0.05). Composite films (F3, F4, and F5) showed better barrier properties in the visible range (350–800 nm), with starch (F1) being the most transparent (p ≤ 0.05). F4 film showed the best technological properties: PVA, solubility and mechanics. The films with the highest percentage of protein, F1 and F4, presented higher (p ≤ 0.05) thermal resistance. In addition, starch favored the crystallinity of films (F3, F4, and F5), providing more orderly matrices. The FTIR and EDS analyzes of the films confirmed the successful interaction of proteins and starch. Therefore, the properties of the elaborated composite films indicate that the interaction between biopolymers is positive to produce packaging for different types of food. [ABSTRACT FROM AUTHOR]

Films with antioxidant properties using acoupa weakfish skin gelatin (Cynoscion acoupa) were obtained after supercritical solvent impregnation with Piper divaricatum essential oil, in order to produce active food packaging. The impregnation process was carried out using CO2 as supercritical solvent, in an autoclave, at 35 °C, pressures of 100, 150, and 200 bar, and times of 60, 90, and 120 min. The film that presented the highest percentage of antioxidant activity was obtained at 100 bar and 60 min (41.63 ± 1.6%). Scanning electron microscopy (SEM) showed that the essential oil had a heterogeneous distribution within the film, confirming its impregnation. The analysis of Fourier-transform infrared spectroscopy (FTIR) showed that the structural properties of the film changed after the process, in which the interaction of the essential oil and the film proteins was confirmed. Impregnation resulted in a film presenting less tensile resistance, greater flexibility, and greater opacity when compared with control film. Thermogravimetric analysis indicated that thermal stability decreased after the impregnation process. The film obtained presented characteristics that suggest its potential as an active packaging for food products. [ABSTRACT FROM AUTHOR]

This study aimed to assess the tissue composition and allometric growth of carcasses of Santa Inês and crossbred Dorper x Santa Inês lambs confined for different periods at three body weight classes. Sixty-four lambs from Santa Inês (SI) and crossbred Dorper x Santa Inês (DSI) were slaughtered. The carcasses were refrigerated at 4 °C for 24 h, and half of the right side carcass was divided into five primary cuts, which were then dissected into bone, muscle, and fat. The corrected cold carcass weight (CCWc) was calculated based on the sum of the cuts. There was no effect of the interactions evaluated (P > 0.05) among the factors tested. CCWc, muscle (kg), fat (kg), bone (%), M:F, M:B, F:B, and M+F:B were influenced by the lambs' genetic group (P < 0.05). An effect of body weight at the beginning of confinement was found only for CCWc, muscle (kg), fat (kg), bone (kg), bone (%), and M:F. The crossbreeding of Santa Inês with breeds Dorper promotes improvements in the qualitative characteristics of the carcass. To obtain better relationships of the quantitative characteristics of the carcass, of sheep introduced in confinements with larger weights, the slaughter weight must be adjusted to that initial weight. [ABSTRACT FROM AUTHOR]