ABSTRACT This work presents the morphology and characterization of chitosan nanoparticles crosslinked with lecithin in the form of nano-onions obtained by an easy, economical, and possibly scalable method from a polymeric precursor known as chitosan. The creation of new products by using shrimp waste is a fundamental factor in avoiding water pollution. These materials have a positive impact as they add value to waste, and they provide the opportunity to decrease pollution. Chitosan nano-onions were synthesized by an environmentally friendly, easy, and inexpensive method using chitosan as a natural source. Chitosan nano-onions (CSNO) were characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and specific surface area (SSA). The nano-onions characterization obtained by FTIR shows the presence of carbonyl groups at a wavenumber of 1752.12 cm-1, while the phosphate groups attributed to lecithin are observed at 1156.88 cm-1. XRD analysis confirmed an amorphous structure, while SEM images presented a globular morphology with concave surfaces. TEM analysis showed that the nano-onions are congregated in a unique structure that includes nanotubes. The CSNO average diameter by DLS was 442.5 nm with an octagonal arrangement, and a polydispersity index (PDI) of 0.532 and 31.9 mV. The average size of CSNO, the PDI, and the value of zeta potential were indicators of a stable dispersion with a specific superficial area measured by the Brunauer-Emmett-Teller (BET) method of 1.4 m2 g-1. The results of the chitosan-lecithin nano-onions characterization indicate changes in the surface of the material with a larger total surface area and pore structure, compared to that of pure chitosan. According to the results of the CHNO characterization, they could be used as adsorbents for contaminants and they also have a potential application in the biomedical area, mainly as drug encapsulation material.

RESUMEN Este trabajo presenta la morfología y caracterización de nanopartículas de quitosano entrecruzadas con lecitina en forma de nanocebollas obtenidas a partir de un proceso sencillo, económico y escalable a partir de un polímero precursor como es el quitosano. La creación de nuevos productos mediante el uso de desechos de camarón es un factor fundamental para evitar la contaminación del agua. Estos materiales tienen un impacto positivo al agregar valor a los desechos y brindan la oportunidad de disminuir la contaminación. La síntesis de nanocebollas de quitosano se logró con un método amigable con el medio ambiente, sencillo y económico, utilizando quitosano como fuente natural. Las nanocebollas de quitosano (CSNO, por su sigla en inglés) se caracterizaron por espectroscopia infrarroja por transformada de Fourier (FTIR), difracción de rayos X (XRD), microscopia electrónica de barrido (SEM), microscopia electrónica de transmisión (TEM), dispersión dinámica de luz (DLS) y área superficial específica (SSA). La caracterización de las nanocebollas obtenidas mediante FTIR muestra la presencia de grupos carbonilo a un número de onda de 1752.12 cm-1, mientras que los grupos fosfato atribuidos a la lecitina se observan a 1156.88 cm-1. El análisis XRD confirmó una estructura amorfa, mientras que las imágenes SEM presentaron una morfología globular con superficies cóncavas. El análisis TEM mostró que las nanocebollas se congregan en una estructura única que incluye nanotubos. El diámetro promedio de las CSNO por DLS fue de 442.5 nm con una disposición octagonal, un índice de polidispersión (PDI) de 0.532 y 31.9 mV. El tamaño promedio de las CSNO, el PDI y el valor del potencial zeta fueron indicadores de una dispersión estable con un área superficial específica (SSA) medida por el método Brunauer-Emmett-Teller (BET) de 1.4 m2 g-1. Los resultados de la caracterización de nanocebollas de quitosano-lecitina indican cambios en la superficie del material con un área superficial total más grande y estructura de poros, en comparación con la de quitosano puro. De acuerdo con los resultados de la caracterización de las CSNO, éstas podrían usarse como adsorbentes de contaminantes y tienen aplicación potencial en el área biomédica, principalmente como material de encapsulación de medicamentos.

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 In the baking industry, different processes and methods of freezing have been used for breadmaking to preserve a quality comparable to that of fresh bread. In this study, the effect of part-baking time, freezing rate, and frozen storage time on part-baked French bread quality was determined. The bread was part-baked for 0, 3 and 6 min, frozen at slow (0.15 °C/min) and fast (1.75 °C/min) freezing rates, stored under freezing conditions for up to 56 days and thawed every 14 days. Part-baked bread was rebaked, and the SV and firmness at 2, 24 and 48 h were obtained. An experiment with a factorial design of 3×2×5 (3 part-baking time, 2 freezing rates and 5 frozen storage times) with analysis of variance (ANOVA) at a confidence level of 95% was carried out. The highest SV was obtained at 6 min of part-baking at a slow freezing rate and decreased as the frozen storage time increased. In contrast, TPA showed that bread firmness increases when the specific volume decreases, and the highest firmness is at 0 min of part-baked time. Relatively long part-baking times allow for firm crumb formation with limited damage to the structure and therefore bread with optimal quality.

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.

Abstract Electrospun nanofibers from gelatin (G), chitosan (CS), and chitosan-polyvinyl alcohol (CS-PVA) were developed by electrospinning process. Mechanical properties were determined by the tensile test, the elastic modulus values of the nanofibers were G (15.418-34.34 MPa) and CS-PVA (17.44-126.427 MPa). The morphological characterization by SEM revealed that the systems with 15% G and 6% CS-PVA showed morphological homogeneity. Structural characterization by FTIR indicated an interaction among some functional groups of the component. Thermal analysis by DSC and TGA showed degradation temperatures for G (330 °C), CS (210 °C to 370 °C), and PVA (310 °C to 420 °C). The contact angles values denoted the hydrophilic nature of the material. Finally, the antimicrobial assay proved that both 15% G and 7% PVA on the CS-PVA system presented the best antimicrobial effect. The results indicate that the electrospun nanofibers fabricated with G or CS-PVA can be used as wound healing dressings.

The purpose of this review is to compile available knowledge on content and anthocyanin type in different pigmented maize (Zea mays L.) varieties. Additionally, the effects of traditional nixtamalization processing on these compounds are listed, and the studies performed to reduce the negative effects of traditional nixtamalization are described. The use of pigmented maize varieties has increased due to their high phenolic compound content, mainly anthocyanins. These compounds are responsible for the blue-red color in plants like maize, and they have antioxidant capacity. Anthocyanins are contained in the aleurone layer at the endosperm and in the pericarp of corn kernels. The non-acyl type anthocyanins, such as cyanidin 3-glucoside, pelargonidin 3-glu-coside and peonidin 3-glucoside are the most abundant compounds in colored maize; they have high antioxidant capacity. Generally, maize varieties with blue, purple and black color kernels contain the highest anthocyanin contents. Traditional nixtamalization processing is highly aggressive for anthocyanins in maize; it causes anthocyanin losses of up to 100 % during traditional nixtamalization. However, alternative processes of nixtamalization, such as lime-cooking extrusion and fractionated nixtamalization can have higher anthocyanin and phenolic content retention. These newer nixtamalization processes can be more efficient than traditional nixtamalization. Nonetheless, more research is needed to further reduce losses of these natural compounds, which are useful for obtaining new nutraceutical products from pigmented maize varieties.

El objetivo de esta revisión es compilar el conocimiento disponible acerca del contenido y los tipos de antocianinas identificadas en diferentes variedades de maíces (Zea mays L.) pigmentados. Principalmente, se pretende identificar el efecto en estos compuestos causado por la nixtamalización tradicional, y especificar los estudios desarrollados con tecnologías alternativas de nixtamalización para disminuir los efectos negativos en la calidad funcional del producto final. El uso de maíces pigmentados se ha incrementado debido al contenido superior de compuestos fenólicos, sobre todo por su contenido de antocianinas. Las antocianinas son los compuestos responsables del color rojo-azul de plantas como el maíz, y poseen propiedades antioxidantes benéficas para la salud. Estos pigmentos se encuentran en la capa de aleurona del endospermo y en el pericarpio del grano. Las antocianinas no aciladas de mayor abundancia en los maíces pigmentados son cianidina 3-glucósido (70 %), pelargonidina 3-glucósido y peonidina 3-glucósido, las cuales poseen una alta capacidad antioxidante. En general, los maíces de variedades de color morado, azul y negro son las que contienen más antocianinas. La nixtamalización tradicional es un proceso agresivo para las antocianinas contenidas en los granos pigmentados, ya que provoca pérdidas hasta de 100 % en los productos obtenidos por esta tecnología. No obstante, se puede retener una mayor cantidad de compuestos fenólicos, antocianinas y mayor capacidad antioxidante en productos obtenidos con nixtamalización por extrusión y nixtamalización fraccionada, los cuales son procesos alternativos eficientes a la nixtamalización tradicional. Sin embargo, son necesarias más investigaciones que permitan disminuir la pérdida de estos compuestos naturales útiles para la obtención de nuevos productos nutracéuticos desarrollados con maíces pigmentados.

Aminas biogênicas em alta concentração podem afetar a qualidade dos alimentos e causar várias doenças, pois estão presentes em produtos como frutos do mar, vinhos e outros produtos fermentados. Subprodutos do camarão são uma fonte rica de proteína hidrolisada que podem ser usadas como suplemento alimentar. Amostras (de subprodutos de camarão) de proteína seca em pó, proteínas hidrolisadas líquidas e farinha da cabeça de camarão foram analisadas para avaliar o conteúdo de histamina e tiramina. As aminas foram extraídas com ácido tricloroacético 5% e posteriormente derivatizadas com o-ftaldialdeído. A separação cromatográfica foi realizada em uma coluna analítica, Chrom SEP C18 SS 5 mm (4,6 mm × 150 mm) com eluição por gradiente, os comprimentos de onda foram λex = 335 nm e λem = 440 nm. A fase móvel utilizada foi uma mistura de tetrahidrofurano, metanol e tampão fosfato a uma vazão de 0,6 mL min-1. Sob essas condições, a repetibilidade (desvio padrão relativo < 6,55%), reprodutibilidade (< 5,60%) e exatidão foram satisfatórias. Os valores de recuperação foram 84,51, 90,75, 95,37, 98,68 e 84,29% para L-tirosina, L-triptofano, L-lisina, tiramina e histamina, respectivamente. Este método tem sido aplicado com sucesso para a quantificação de aminoácidos precursores e aminas biogênicas em matrizes diversas.

Biogenic amines in high concentration can affect the quality of foods and cause several diseases since they are present in products like seafood, wines, and other fermented products. Shrimp by-products are a rich source of protein hydrolysate that can be used as dietary supplements. Samples (from shrimp by-products) of dry protein powder, liquid protein hydrolysate and flour of shrimp head were analyzed to evaluate the histamine and tyramine contents. Amines were extracted with trichloroacetic acid 5% and derivatized with o-phthaldialdehyde. The chromatographic separation was performed in an analytical column, Chrom SEP SS C18 5 µm (4.6 mm × 150 mm) and a fluorescence detector was used with wavelengths at λex = 335 nm and λem = 440 nm. The mobile phase was a mixture of tetrahydrofuran, methanol and phosphate buffer at a flow rate of 0.6 mL min-1 using elution gradient. Under these conditions, the repeatability (relative standard deviation, RSD < 6.55%), reproducibility (< 5.60%) and accuracy were of satisfying quality. The recovery values were 84.51, 90.75, 95.37, 98.68 and 84.29% for L-tyrosine, L-tryptophan, L-lysine, tyramine and histamine, respectively. This method has been successfully applied for the quantification of precursor amino acids and biogenic amines in different matrices.

The chitosan showed inhibition of spore germination at 24 h on Cladosporium cladosporioides (70.99 ± 12.53 and 32.72 ± 10.85% for QB and QA, chitosans, respectively). Chitosan caused morphometric changes on spore evidenced by excessive swelling and delay on the germ tube. However, in comparison with the controls, the chitosan not inhibited the colony radial extension rate.

El quitosano mostró inhibición sobre la germinación de esporas de Cladosporium cladosporioides a las 24 h (70.99 ± 12.53 y 32.72 ± 10.85%, QB y QA, respectivamente). El quitosano causó cambios morfométricos sobre las esporas, evidenciado por excesivo hinchamiento y disminución de la elongación del tubo germinal. Sin embargo, en comparación con los controles, el quitosano no inhibió las velocidades de extensión radial de los cultivos.

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.

The effect of 3.4 g L-1 of chitosan (46.31 kDa) on Alternaria tenuissima isolated from safflower variety S-518. The incidence rate of seeds planted in Alternaria infected PDA was 19.5%. Chitosan incorporated in PDA inhibited the germination of spores in 90.2% at 24 h with respect to the acid and the control of the colony radial growth at 216 h was decreased. The incidence of A. tenuissima in seeds treated with chitosan for 30 min and cultured on PDA showed no significant difference (P<0.05) compared to controls. Chitosan did not decrease the percentage of safflower seed germination over control.

Se evaluó el efecto de 3.4 g L-1 de quitosano (46.31 kDa) sobre Alternaria tenuissima aislada de semillas de cártamo variedad S-518. El porcentaje de incidencia de semillas infectadas por Alternaria sembradas en PDA fue de 19.5%. El quitosano incorporado en PDA, inhibió la germinación de esporas en 90.2% a las 24 h con respecto al control ácido y el crecimiento radial de la colonia a las 216 h fue disminuido. La incidencia de A. tenuissima en semillas tratadas con quitosano por 30 min y cultivadas en PDA no mostró diferencia significativa (P<0.05) con respecto a los controles. El quitosano no disminuyó el porcentaje de germinación de semillas de cártamo con respecto al control.

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.

El sulforafano es un isotiocianato con propiedades antimicrobianas y anticarcinogénicas, se encuentra en una amplia variedad de vegetales del género Brassica oleracea, considerándose las más importantes el brócoli y repollo. El objetivo de esta investigación fue cuantificar sulforafano en las partes comestibles de brócoli y en hojas de repollo por cromatografía líquida de alta resolución (HPLC). La preparación de la muestra para la cuantificación del sulforafano incluye la conversión de glucorafanina a sulforafano (45 ± 2°C durante 2,5 h), extracción con diclorometano, purificación del extracto en columnas de extracción de fase sólida, y detección por HPLC-UV. En brócoli la concentración de sulforafano está en el rango de 214 µg/g bs (tallos) a 499 µg/g bs (inflorescencias). El repollo morado (101,99 µg/g bs) presentó valores mayores de sulforafano que el repollo verde (7,58 µg/g bs). Las inflorescencias de brócoli y las hojas de repollo morado son ricos en sulforafano.

Sulforaphane is an isothiocyanate which has antimicrobial and anticarcinogenic properties, this compound is found in a wide variety of plants from genus Brassica oleracea, being the most important broccoli and cabbage. The objective of this research was to quantify sulforaphane in the edible parts of broccoli and cabbage leaves by high-performance liquid chromatography (HPLC). Sample preparation for the quantification of sulforaphane include the conversion of glucoraphanin to sulforaphane (45 ± 2 °C for 2.5 h), extracted with dichloromethane, purification of the extract in columns of solid phase extraction and detection by HPLC- UV. Sulforaphane concentration in broccoli is in the range of 214 µg/g DW (stems) to 499 µg/g DW (inflorescences). The purple cabbage (101.99 µg/g DW) has values greater than the green cabbage (7.58 µg/g DW). The inflorescences of broccoli and red cabbage leaves are rich in sulforaphane.