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Fish industry residues are used due to their easy transformation into several products and because they have nutrients with high biological value, being rich in proteins and fatty acids. The gelatin extraction process from the skin of kumakuma (Brachyplatystoma filamentosum) using sodium hydroxide was optimized and the product was characterized. The optimized conditions established in the process were 6 h extraction at 58°C, with yield and gel strength at 19.7% and 244.3 g, respectively, which is considered acceptable for foods. The maximum desirability condition was 0.998. When the technological properties of the gelatin extracted from fish skin was compared with commercial gelatin, a difference (p < 0.05) was observed for all parameters analyzed, but within the appropriate range for gelatin. The gelatin obtained from kumakuma skin may be a new alternative to replace gelatin from mammals, besides contributing to less fish residue released into the environment.Optimización y caracterización de la gelatina de piel de kumakuma (Brachyplatystoma filamentosum) RESUMEN Los residuos de la industria pesquera se utilizan debido a su fácil transformación en diversos productos, también por sus nutrientes de gran valor biológico, los cuales son ricos en proteínas y ácidos grasos. Se optimizó el proceso de extracción de gelatina de piel de kumakuma (Brachyplatystoma filamentosum) mediante la utilización de hidróxido sódico y se caracterizó el producto. Las condiciones optimizadas establecidas en el proceso fueron 6 h de extracción a 58°C, con un rendimiento y resistencia del gel de 19,7% y 244,3 g, respectivamente, lo cual se consideró aceptable para los alimentos. La máxima condición aceptable fue 0,998. Cuando se compararon las propiedades tecnológicas de la gelatina extraída de la piel del pez con la gelatina comercial, se observaron diferencias (p < 0,05) en todos los parámetros analizados, aunque dentro del rango apropiado en lo que concierne a la gelatina. La gelatina obtenida de la piel de kumakuma podría ser una nueva alternativa para remplazar la gelatina de mamíferos, además de contribuir a reducir los residuos de pescado vertidos en el medioambiente.

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Chitosan is a biopolymer with high added value, and its properties are related to its molecular weight. Thus, high molecular weight values provide low solubility of chitosan, presenting limitations in its use. Based on this, several studies have developed different hydrolysis methods to reduce the molecular weight of chitosan. Acid hydrolysis is still the most used method to obtain low molecular weight chitosan and chitooligosaccharides. However, the use of acids can generate environmental impacts. When different methods are combined, gamma radiation and microwave power intensity are the variables that most influence acid hydrolysis. Otherwise, in oxidative hydrolysis with hydrogen peroxide, a long time is the limiting factor. Thus, it was observed that the most efficient method is the association between the different hydrolysis methods mentioned. However, this alternative can increase the cost of the process. Enzymatic hydrolysis is the most studied method due to its environmental advantages and high specificity. However, hydrolysis time and process cost are factors that still limit industrial application. In addition, the enzymatic method has a limited association with other hydrolysis methods due to the sensitivity of the enzymes. Therefore, this article seeks to extensively review the variables that influence the main methods of hydrolysis: acid concentration, radiation intensity, potency, time, temperature, pH, and enzyme/substrate ratio, observing their influence on molecular weight, yield, and characteristic of the product.

This research aimed to assess the properties of biodegradable films prepared with lyophilized myofibrillar proteins (LMP) from fish filleting residues, fatty acids (stearic, palmitic, and caproic), and surfactant (SLS). The films were characterized to assess the effects of adding those components. Adding fatty acids and SLS resulted in more flexible films with higher elongation values compared to the LMP film. The films prepared with 5% stearic acid and 10% SLS and with 10% palmitic acid and 20% SLS had higher tensile strength compared to the LMP film. Solubility reached 100% in the films added with 10% fatty acids with and without SLS. Oncreasing the concentration of fatty acids and SLS led to less transparent films. Microscopy analysis showed changes in the morphological structure of the films added with fatty acids and SLS, resulting in whitish films when greater SLS contents were used.

Considering the quality of meat produced in the TS or TSPS, it is concluded that finishing buffaloes in the pasture still represents the best alternative. © 2016 Society of Chemical Industry.

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This research studied the effect of thermoplastic extrusion on the expansion index (EI), water absorption index (WAI), water solubility index (WSI), and sensory acceptance (SA) of a snack from rice grits, polished rice grains, and shrimp. A 2 3 factorial design was used with independent variables, temperature in the third extruder zone (63.2-96.8°C), initial moisture (106.4-173.6 g/kg), and shrimp content (16-184 g/kg), whereas EI, WAI, WSI, and SA were the responses. Through the surface-response methodology, the formulation with 80 g/kg shrimp and 130 g/kg initial moisture processed at 85°C in the third extruder zone was considered optimal. The product had good EI, WAI, and SA, 65.6 g/kg moisture, 24.0 g/kg lipids, 89.5 g/kg proteins, 34.2 kg/kg ashes, 72.4 g/kg fibers, and 714.3 g/kg carbohydrates. The product is an alternative for using rice grit, which has low commercial value, while also fully using the regional shrimp.