Efforts aimed at reduction of fishing waste generated during the evisceration and filleting are scarce. The fishing waste is used in the production of low value-added products, such as flours or silages. It is important to visualize an alternative and profitable use of this waste, as it constitutes a serious environmental problem. This research determined the antioxidant properties of collagenous extracts of skin and galls of Oreochromis sp. The raw materials were characterized by proximal chemical analysis. Three treatments were applied to extract the collagen: salt-soluble collagen, acid-soluble collagen (ASC), and pepsin-hydrolyzed collagen (PHC). The collagenous fractions were hydrolyzed (0.1% pepsin). The recovered collagen yield and antioxidant activity were determined to hydrolyzed collagen (HC) and nonhydrolyzed collagen (NHC). The ASC skin showed the highest extraction yield (3.02%). For galls, only the PHC extraction was feasible (0.16%). Antioxidant analysis of NHC did not reveal radical scavenging activities. HC displayed a 2,2-diphenyl-1-picrylhydrazyl %RSA of 22.58 (ASC skin) and 10.34% (PHC galls), and a 2,2′-azino-bis[3-ethylbenzothiazoline-6-sulfonic acid] %RSA of 30.40% (PHC skin) and 29.43% (PHC galls), respectively. The ASC skin and PHC gall extracts exhibited 94.40% and 81.54% in ferric-reducing antioxidant power, and 43.63 and 38.08 μ g ascorbic acid equivalents per milli liter for total antioxidant capacity, respectively. The collagen extracts showed %RSA and chelation of pro-oxidant metal ions. Different mechanism of antioxidant action was identified for the extracts: radical scavengers for HC and metal ion chelators for NHC. In conclusion, red tilapia skin collagen is recommended as an active ingredient of nutraceuticals, pharmaceuticals, or functional foods, for the identified bioactive properties.

Viticulture has migrated to organic management to reduce environmental impact. Grapes harvested in organic vineyards (ORGs) could have a better polyphenol profile than conventional vineyards (CONs). The objective was to evaluate the relationship between agricultural management, elemental soil profile, and grape bioactive compounds (var. Syrah and Tempranillo). Soil components were determined from CON and ORG vineyards; they were correlated with bioactive compounds in grape skin and seed through principal component analysis (PCA). The ORG vineyard presented higher moisture (4.50–5.72%), clay (31.70–40.55%), organic matter (OM) (9.44–11.01%), P (108.72–122.16 mg/kg), N (0.27 mg/kg), and oxides (Fe₂O₃, SiO₂, MnO, TiO₂) in soil and phenolic compounds (myricetin, quercetin, resveratrol, ellagic acid, others) and antioxidant capacity in grape skin and seed. Regarding PCA (>74.20% of variance), the first component showed positive correlations (>0.60) between pH, moisture, clay, and soil oxides (MgO, K₂O, Al₂O₃), which favored biosynthesis in grape skin and seed phenols (catechin, gallic acid, vanillic acid, and rutin). The second component showed positive correlations between OM, silt, soil oxides, antioxidant capacity, and phenols in grape skin and seed. Finally, the edaphic conditions of the ORG vineyard allowed for one to obtain optimal grapes for winemaking due to their higher phenol content.

Chocolate coatings are semisolid suspensions of fine particles from sugar, cocoa, non fat milk solids in an oily phase. Processing steps of chocolate include mixing, refining, conching, tempering, molding, and packing. Tempering is a directed pre-crystallization that consists of shearing chocolate mass at controlled temperatures. The effect of mixing and tempering process on the particle size distribution and rheological behavior of dark chocolate coatings were evaluated. Each sample was melted (65 °C, 15 min) and tempered following three different procedures usually recommended for chocolate. Proximate composition analysis, specific surface area, mean particle diameter, consistency index (K), flow index (n), G′, G″ and electron micrographs (4000×) were obtained. All samples followed Casson flow model and (n) showed a pseudoplastic behavior. Higher values of K were shown by tempering process 3. Shear increased chocolate storage module (G′) and its stability. Samples without tempering and shearing have shown higher values of particle size. Las coberturas de chocolate son suspensiones semi-sólidas de partículas pequeñas de azúcar, cacao, sólidos no grasos de leche en una fase oleosa. Los pasos del procesamiento de chocolate incluyen mezclado, refinación, conchado, temperado, moldeo y empacado. El temperado es una pre-cristalización directa que consiste en cizallar la masa de chocolate a temperaturas controladas. Se evaluó el efecto del mezclado y del temperado sobre la distribución del tamaño de partícula y el comportamiento reológico de coberturas de chocolate obscuro. Las muestras fueron fundidas (65 °C, 15 min) y temperadas siguiendo tres procedimientos recomendados. Se determinaron el análisis proximal, área superficial específica, diámetro medio de partícula, índice de consistencia (K), índice de flujo (n), módulos viscoelásticos (G′ y G″), y se usó micrografía electrónica, SEM (4000×). Todas las muestras presentaron un comportamiento al flujo ajustado al modelo de Casson. Los cambios de K estuvieron en función del proceso de temperado usado, pero (n) mostró cambios en su comportamiento pseudoplástico. Los mayores valores de K se obtuvieron para el temperado 3 y los menores para el temperado 1. El corte incrementó el módulo de almacenamiento (G′) y en consecuencia su estabilidad. Las muestras sin temperado y corte mostraron el mayor tamaño de partícula (9.17 μm).

Agricultural residues can be taken advantage of and be used to produce edible mushrooms through a biotransformation procedure. Mushrooms are beneficial species for humans, acting as antioxidant, antidiabetic, hypo-cholesterolemic, antitumor, anticancer, immunomodulating, antiallergic, nephroprotecting, and antimicrobial agents. The current study analyzed the influence of the origin of the nitrogen source on the antioxidant capacities of the Pleurotus ostreatus mushroom. The substrates were lignocellulosic residues and their moisture, ash, carbohydrate, and lignin content along with pH and antioxidant capacity were determined. Later, P. ostreatus mushrooms were produced in those residues, and their antioxidant capacity was determined. Edible mushrooms of the species P. ostreatus cultured in a mixture of sawdust, oak, and pasture were a viable source of antioxidant substances because their ethanolic extracts possessed an antioxidant capacity of 92.74% 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical assay. Direct influence of the growth substrate on the antioxidant properties of P. ostreatus was found. The use of different solvents (methanol, ethanol, or acetone) had no significant effect on the antioxidant properties of the extract.