Abstract Biomaterials developed with biopolymers contribute to the healing process of healthy or diabetic patients. The objective of the present study was to evaluate the effect of honey incorporation (0.3, 0.6, and 1.2 g/100 mL) in chitosan/collagen/glycerol composite films. The Ch/Coll/1.2H films revealed the greatest percentage of elongation (27.10%) and Young´s modulus (65.58 MPa). The barrier properties (WVTR and WVP) exhibited a significant increase when the honey was incorporated into the films. The absorption capacity, solubility, and enzymatic biodegradability were lower in films containing honey. The chemical interactions between the functional groups of the films were verified by FTIR. The morphology studied by SEM confirmed the mixture’s homogeneity. Finally, all formulations exhibited antibacterial properties against Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes, and Salmonella Typhimurium. The aforementioned properties of formulated dressings are suitable for their potential application in chronic wounds.

Abstract Escherichia coli is one of the most important bacteria associated with the consumption of meat products causing human disease, with bovines as the main reservoir for this organism. Escherichia coli serogroups producing the Shiga toxin (referred as STEC) include both O157:H7 and non-O157 strains can cause Hemolytic Uremic Syndrome (HUS). STEC have been previously founded in raw meat sampled at slaughterhouses. The goals of this study were 1) to detect STEC O157 and non-O157 strains in meat cuts and products (beef and pork) in TIF and non-TIF slaughterhouses, as well as butcheries, in southern Sonora, Mexico, and 2) to verify the antibiotic resistance/susceptibility pattern of E. coli strains, which contain any toxin- producing gene. To achieve the first aim, two selective media (TS-SMAC agar and Rainbow® agar O157) were employed to obtain putative O157:H7 colonies, followed by multiplex PCR for the stx1, stx2, eaeA, and rfB genes, using the O157:H7 serotype as a control. No STEC O157 was found in the beef products, but some non-O157 isolates were found. These isolates contained the stx2 pathogenicity gene (1.40 %, 3/224) and/or the fliCH4 flagellar antigen (1.78 %, 4/224). This work also confirmed the susceptibility/resistance of strains with the stx2 and/or fliCH4 genes to several antibiotics and multi- resistance of all or some of these strains to trimethoprim/sulfamethoxazole, tetracycline, clarithromycin, penicillin G, oxacillin, ampicillin, and cefazolin.

Abstract Sorghum bran has a high antioxidant capacity due to the high concentrations of phenolic compounds. During decortication of the sorghum grain to obtain the bran, lipid oxidation reactions may occur that cause deterioration in its quality. To avoid this, thermal stabilization processes such as extrusion are used. The objective of this work was to evaluate chemical, stability of phenolic compounds and antioxidant capacity changes of extruded red sorghum bran. Raw sorghum bran (SC) and extruded (SE) sorghum bran were stored for 42 days and chemical (peroxide index, pH, free fatty acid), phenolic compounds, antioxidant capacity and phenolic acids determinations were carried out. The type of bran was the factor that most affected results of the chemical evaluations. The SE showed greater stability in quality than the SC, which had significant changes in free fatty acid and peroxide index. The content of phenolic compounds and the antioxidant capacity of both types of bran were not modified by the effect of storage. However, the SE presented higher levels of both parameters than the SC. The sorghum bran extrusion process retards enzymatic oxidation of lipids and improves the extraction of phenolic compounds.

Resumen El salvado de sorgo posee una alta capacidad antioxidante debido a su elevado contenido de compuestos fenólicos. Durante el decorticado del grano para la obtención del salvado, pueden presentarse reacciones de oxidación lipídica que deterioran su calidad. Para evitar esto, se emplean procesos de estabilización como la extrusión. El objetivo de este trabajo fue evaluar los cambios químicos en los compuestos fenólicos y la capacidad antioxidante del salvado de sorgo rojo extrudido. Los salvados de sorgo crudo (SC) y extrudido (SE) se almacenaron durante 42 días para poder evaluar los cambios químicos (índice de peróxidos, pH y ácidos grasos libres), en los compuestos fenólicos, su capacidad antioxidante y la presencia de ácidos fenólicos. El tipo de salvado fue el factor que más afectó los resultados de las evaluaciones químicas. La calidad del SE fue más estable en comparación con la del SC, el cual tuvo cambios significativos de ácidos grasos libres e índice de peróxidos. El contenido de compuestos fenólicos y la capacidad antioxidante de ambos tipos de salvado no se modificaron significativamente (p > 0.05) por efecto del tiempo de almacenamiento, sin embargo, el SE presentó niveles superiores en compuestos fenólicos y capacidad antioxidante que el SC. El proceso de extrusión del salvado de sorgo retarda la oxidación enzimática y mejora la extracción de los compuestos fenólicos.

O objetivo desta pesquisa foi estudar as propriedades funcionais e a composição centesimal de três diferentes farinhas preparadas dos cladódios da palma forrageira. Palmas forrageiras não maturadas foram secadas a 60 °C, 70 °C e 80 °C, e as farinhas obtidas foram analisadas na sua composição química, no perfil dos aminoácidos, na composição de ácidos graxos, nas propriedades funcionais e na cor. Não houve diferenças significativas nos teores de proteína bruta, lipídios totais, fibra bruta e de cinzas totais nas farinhas pelo efeito da temperatura de secagem. No entanto, durante a secagem a 80 °C foi observada uma redução da capacidade de retenção de água (55%) e da intensidade da cor verde (34%), característica da palma forrageira. A tirosina, a prolina, o ácido aspártico e o ácido glutâmico foram encontrados em alta concentração. Nos lipídios das farinhas os ácidos graxos mais abundantes foram o ácido palmítico (C16: 0), o ácido linoleico (C18: 2n6), o ácido linolênico (C18: 3n3) e, o ácido oleico (C18:1n9). As farinhas dos cladódios da palma forrageira preparadas a 60 °C apresentaram uma alta qualidade em termos de suas propriedades nutricionais e funcionais.

The objective of this research was to study the functional properties and proximate composition of three different flours prepared from cactus pear cladodes. Immature cactus pear cladodes were dried at 60 °C, 70 °C and 80 °C. The flours were analyzed for chemical composition, amino acid profile, fatty acid composition, functional properties and color. The analyses showed no significant differences in crude protein, total lipid, crude fiber and total ash content in the flours, possibly due to the drying temperature effect. Nevertheless, during the drying at 80 °C, a reduction of the water holding capacity (55%) was observed, along with a reduction of the green color intensity (34%) - characteristic of cactus pear. The heating produced larger concentrations of tyrosine, proline, aspartic acid, and glutamic acid. In the lipids of the flours, the most abundant fatty acids were palmitic acid (C16:0), linoleic acid (C18:2n6), linolenic acid (C18:3n3), and oleic acid (C18:1n9). The cladodes flours prepared at 60 °C presented a higher quality regarding their nutritional and functional properties.

Riboflavin is a water-soluble vitamin of the B complex, and its contribution is essential for the good functioning of the body. Milk is one of the main sources of riboflavin in the human diet; however, in most foods is degraded during conventional thermal processes and storage. In this paper the content of riboflavin in commercial dairy products, milk for direct consumption and yogurt, was determined by high performance liquid chrornato graphic analysis (HPLC) with fluorescence detection. Sample preparation includedan acid hydrolysis (HCL 0.1 N) followed by an enzymatic digestion and a protein precipitation at the end (TCA100%). For the HPLC analysis an isocratic bomb program was used (0.005 M ammonium acetate-methanol, 72:28 vlv). Riboflavin concentrations in yogurt samples were 0.289-3.078 µgB2/gDW, while in the ultra-high-temperature pasteurized milk and pasteurized milk was 0.61 -13.64 µgB2/g DW and 11.73-15.41 µgB2/g DW, respectively. Milk for direct consumption and yogurt are good sources of riboflavin; its regular consumption helps to satisfy daily requirements.

La riboflavina (B2) es una vitamina hidrosoluble del complejo B, cuyo aporte nutritional es imprescindible para el buen funcionamiento del organismo. La leche es una de las principales fuentes de riboflavina en la dieta humana, sin embargo, en la mayoría de los alimentos se degrada durante los procesos térmicos convencionales y en el almacenamiento. En el presente trabajo se determinó el contenido de riboflavina en productos lácteos comerciales, leches para consumo directo y yogurt, por cromatografía líquida de alta resolución (HPLC) con detección por fluorescencia. La preparación de la muestra incluye una hidrólisis acida (HC10. IN), seguida por una digestión enzimática, y por último, la precipitación de proteínas (TCA100 %). En el análisis cromatográfico se utilizó un sistema isocrático (acetato de amonio 5 mM-metanol, 72:28 v/v). El contenido de riboflavina de las muestras de yogurt estuvo en el rango de 0,289 - 3,078 µ/g BS, mientras que en la leche ultrapasteurizada y pasteurizada de 0,61-13,64 µg/gBS y 11,73-15,41 µg/ g BS, respectivamente. Las leches para consumo directo y el yogurt comercial son fuentes de riboflavina, y su consumo regular puede ayudar a satisfacer los requerimientos diarios.