Abstract The objective of this study is to evaluate the effect of β-agonists (BA), Zilpaterol Hydrochloride (ZH), and Ractopamine Hydrochloride (RH) on the biometric parameters and the muscle fiber thickness in Pelibuey lambs (n = 6). The control group was fed a standard diet (16% protein content and 12 MJ per day); treatment groups received a standard diet supplemented with ZH or RH for 37 days and was assessed presence of BA in samples of muscle tissues, and urine. The effect of Daily Weight Gain (DWG) and Food Conversion Rate (FCR) on muscle fiber thickness was determined by Scanning Electron Microscopy (SEM) and Digital Image Analysis (DIA). Results showed an increase of 30% in DWG in the ZH group, compared with RH. While FCR was lower in ZH (3.83) than in RH (4.85). In both BA treatments, the withdrawal time was sufficient to minimize drug concentration in meat. In contrast with the control group, muscle fiber thickness increased in BA treated groups (ZH = 69.2%, and RH = 15.6%). In conclusion, ZH displayed a higher carcass yield in Pelibuey lambs.

Resumen El objetivo de este estudio fue evaluar el efecto de los β-agonistas (BA), Clorhidrato de Zilpaterol (ZH) y el Clorhidrato de Ractopamina (RH) sobre los parámetros biométricos y el grosor de la fibra muscular en corderos Pelibuey (n = 6). El grupo control recibió una dieta estándar (DS) (16% de contenido de proteína y 12 MJ por día), mientras que los grupos de tratamiento recibieron DS+ZH o DS+RH durante 37 días. Se evaluó la presencia de BA en tejido muscular y orina, determinó el aumento de peso diario (DWG), la tasa de conversión de alimentos (FCR) sobre el grosor de la fibra muscular, mediante microscopía electrónica de barrido (SEM) y análisis de imagen digital (DIA). Los resultados mostraron 30% más en DWG en el grupo ZH, que en RH. Mientras que la FCR fue menor en ZH (3.83) que en RH (4.85). El tiempo de supresión aplicado fue suficiente para que los grupos ZH y RH no mostraran residuos. En contraste con el grupo de control, el grosor de las fibras musculares aumentó en los grupos tratados con BA (ZH = 69.2% y RH = 15.6%).

Abstract Introduction: Colon cancer diagnosis is usually performed late; so, it is necessary to search for prevention options. In vivo models are an option for the evaluation of chemopreventive agents, which are based mainly on the induction and promotion of carcinogenesis; however, they take a long time. This work aimed to evaluate and propose a carcinogenesis model, with tumor manifestation in a short time to prove the efficacy of chemopreventive compounds. Method: Colon carcinogenesis was induced in three groups (n = 7) male BALB/c mice with azoxymethane (AOM) and dextran sodium sulfate (DSS). The damage was assessed 14 weeks after the induction. Protocols were: 1) P1: two AOM injections and two DSS cycles at 1.5 % for five days, with three resting days between cycles; 2) P2: one AOM injection and two DSS cycles at 2 % for seven days with five rest days, and 3) P3: one AOM injection and two DSS cycles at 2 % for four days, with four resting days. Negative control was used in parallel, P0: with one injection of saline solution and water ad libitum. Weight, disease activity index (DAI), survival, tumor incidence, lipids, and protein oxidation were determined. Results: P2 showed greater severity in the assessed signs (100 % tumor incidence, colon weight/length ratio 101.68 ± 2.99 mg/cm), with low survival (43 %). P1 depicted lower mortality (14 %) and 83 % tumor incidence, without a significant difference to P2. P3 developed the disease but to a lesser degree (33 % tumor incidence). Furthermore, the three protocols showed lipid oxidation (0.4-0.58 ng/μg of protein) and proteins oxidation (0.6-1 ng/μg of protein). The P1 and P3 induction protocols presented less mortality, weight loss, and acceptable DAI, a weight/length ratio higher than the negative control and presence of tumors. Discussion or Conclusion: The use of AOM (10mg/kg) combined with DSS (1.5-2 %) are suitable models to evaluate the carcinogenic effect of compounds of interest, inflammation signs, lipids and proteins oxidation and a survival number adequate to perform the statistical analysis leading to accurate conclusions. Therefore, P1 and P3 are protocols that can be used in chemoprevention assays with satisfactory results.

Resumen Introducción: El diagnóstico del cáncer de colon suele realizarse de forma tardía, por lo que suelen buscarse varias opciones para su prevención. Para esto, los modelos in vivo resultan una opción para la evaluación de agentes quimiopreventivos. Estos modelos se basan principalmente en la inducción y promoción de la carcinogénesis; sin embargo, tardan mucho tiempo. Este trabajo tuvo como objetivo evaluar y proponer un modelo de carcinogénesis con manifestación tumoral en menos tiempo, para comprobar la eficacia de compuestos quimiopreventivos. Método: Se indujo carcinogénesis de colon en tres grupos (n = 7) de ratones macho BALB/c con azoximetano (AOM) y dextran sulfato de sodio (DSS). El daño se evaluó 14 semanas después de la inducción. Los protocolos fueron los siguientes: 1) P1: dos inyecciones de AOM y dos ciclos de DSS al 1.5 % durante cinco días, con tres días de descanso entre ciclos; 2) P2: una inyección de AOM y dos ciclos de DSS al 2 % durante siete días, con cinco días de descanso, y 3) P3: una inyección de AOM y dos ciclos de DSS al 2 % durante cuatro días, con cuatro días de reposo. Se utilizó control negativo en paralelo, P0: con una inyección de solución salina y agua ad libitum. Se determinó peso, índice de actividad de la enfermedad (DAI), supervivencia, incidencia de tumores, lípidos y oxidación de proteínas. Resultados: P2 mostró mayor severidad en los signos evaluados (100 % de incidencia de tumores, peso/longitud de colon 101.68 ± 2.99 mg/cm), con baja supervivencia (43 %); P1 presentó menor mortalidad (14 %) y 83 % de incidencia de tumores, sin diferencia significativa con P2. P3 desarrolló la enfermedad, pero en menor grado (33 % incidencia de tumores). Además, los tres protocolos mostraron oxidación de lípidos (0.4-0.58 ng/μg de proteína) y proteínas (0.6-1 ng/μg de proteína). Los protocolos de inducción P1 y P3 presentaron menor mortalidad, pérdida de peso y DAI aceptable, relación peso/longitud de colon superior al control negativo y presencia de tumores. Discusión o Conclusión: El uso de AOM (10mg/kg) combinado con DSS (1.5-2 %) son modelos adecuados para evaluar el efecto carcinogénico de compuestos de interés, signos de inflamación, oxidación de lípidos y proteínas, y un número de supervivencia necesario para realizar el análisis estadístico que conduzca a conclusiones certeras. Por tanto, P1 y P3 son protocolos que pueden utilizarse con resultados satisfactorios para los ensayos de quimioprevención.

Abstract Seaweeds or marine macroalgae are sources of industrial important macro compounds. This work characterizes the chemical composition, morphology, cellular structure, morphometric parameters, protein distribution, density, and quantifies the chemical elements of three seaweed species. The morphological characterization performed by Digital Image Analysis (DIA) showed that the length/width ratio for UF (Ulva fasciata) (15.4/10.9 cm) was greater compared to SC (Sargassum cymosum) and GS (Grateloupia subpectinata) (8.9/7.6 cm and 87/5.3 cm). Using Schiff's and Coomassie blue reagents, identified carbohydrates and proteins in cells and protein bodies (PB). Cell morphology showed larger cells in the SC cortex (457.8 µm2) and smaller cells in the SC meristoderm (80.5 µm2). PB density (PB/area) and distribution (area occupied by the cell, %) were higher in the cortex of GS (10468 PB/mm2, 20%) and lower in the meristoderm of SC (917 PB/mm2, 7%). Chemical analysis showed as major compounds: carbohydrates (12-46%), ashes (13-42%), and proteins (6-17%). Meanwhile, the concentration of metals was below the toxicity level. These results contribute to the knowledge of the structure-function relationship of seaweeds metabolites which could be a source of compounds of interest for the industrial sector.

Abstract The non-toxic Jatropha curcas flour has been characterized in numerous studies that have demonstrated its nutritional properties and its safe consumption for humans; however, the refined oil has not been characterized biochemically and toxicologically. Its main physicochemical parameters have been determined as well as its fatty acids profile, which showed to be like commercial oils. Its acute toxicity assessment revealed that at a dose of 2000-5000 mg/kg of body weight, the fatty acids were innocuous, indicating its edible grade. Its biological assessment was also performed in rats, using a standard diet, and substituting it with refined and not refined J. curcas oil, without observing differences in weight gain, interference in protein efficiency, and change in liver weight due to the oil consumption, indicating that it is safe as food. Hence, the non-toxic J. curcas seeds of Mexico could be a source of edible oil.

Abstract The oil obtained from Moringa oleifera seeds is mainly composed of oleic acid and in less proportion by linoleic and α-linolenic acids. It also contains phospholipids and other minority components, like enzymes, alkaloids, and glycosinolates some of which can generate undesirable characteristics and toxicity; therefore, refining processes are recommended for their removal. The aim of this work was to evaluate the effect of chemical refining on acute toxicity, fatty acid composition, and physicochemical properties, and of M. oleifera seed oil obtained from a Mexican variety. The oil was extracted by mechanical pressing of the seeds and then submitted to chemical refining. The crude and refined oils were characterized by determining the following parameters: acute toxicity in a murine model, fatty acid profile; iodine, saponification, and peroxide indexes; titratable acidity; and antioxidant capacity. Results showed that the M. oleifera seed oil did not present acute toxicity in the range of 300-2,000 mg/kg; therefore, could be used for human nutrition. The refining process did not have a significant effect (p < 0.05) on the content of oleic (69%), linoleic (0.74%), and α-linolenic (1.97%) acids. After the refining process, the iodine and saponification indexes increased. In contrast, the peroxide index, acidity, β-carotene content, and antioxidant capacity decreased.

Resumen El aceite de Moringa oleifera está compuesto principalmente de ácido oleico, linoleico y α-linolénico, también contiene fosfolípidos y otros componentes minoritarios, como enzimas, alcaloides y glucosinolatos, compuestos que pueden generar características no deseadas y/o toxicidad, sin embargo, éstos pueden eliminarse mediante un proceso de refinación. El objetivo de este trabajo fue evaluar el efecto de la refinación química sobre la toxicidad aguda, la composición de ácidos grasos, y las propiedades fisicoquímicas del aceite de semilla de M. oleifera de una variedad mexicana, para ésto, el aceite se extrajo por prensado mecánico de las semillas para someterse a refinación química. Al aceite crudo y refinado se les determinó toxicidad aguda probada en un modelo murino, así como también el perfil de los ácidos grasos, los índices de yodo, saponificación y peróxido, además de la acidez, y capacidad antioxidante. Los resultados mostraron que el aceite de semilla de M. oleifera no presentó toxicidad aguda en el intervalo de 300-2,000 mg/kg; por lo que podría ser utilizado para consumo humano. El proceso de refinación no tuvo efecto significativo (p < 0.05) sobre el contenido del ácido oleico (69%), linoleico (0.74%) y α-linolénico (1.97%). Después del proceso de refinación, aumentó el valor del índice de yodo y de saponificación, mientras que el índice de peróxido, la acidez, el contenido de β-caroteno y la capacidad antioxidante disminuyeron.

Abstract Honey is a food product with high nutritional and pharmacological value. Most studies of this product have focused on studying the properties of honey produced by Apis mellifera, which has been used in alternative medicine, highlighting the antioxidant, antimicrobial and anti-inflammatory activities, among others. In this work, we identified the floral origin, the concentration of soluble protein and phenolic compounds, and we assessed the antioxidant and chelating activity of the honey produced by Melipona beecheii and Frieseomelitta nigra from the community of San Marcos in Tenosique, Tabasco, México. The results show that the honey produced by M. beecheii was of monofloral origin (Eugenia sp.); while that of F. nigra is of polyfloral origin, derived mainly from the species Piper sp., aff. Brosimum, Asteraceae, Ziziphus sp., Haematoxylum campechianum). Honey produced by F. nigra show higher concentration of phenolic compounds, it is more effective in entrapping the DPPH and superoxide radicals, and exhibits better copper chelating potential. The honey of M. beecheii has a higher capacity for uptake of ABTS radicals and chelation of iron. The uptake capacity of the hydroxyl radical was similar for both honeys. This work highlights the importance of having palynological and biochemical analyzes on the honeys of native stingless bees, because of their therapeutic potential, where for many species there is a lack of information.

Resumen La miel es un producto alimenticio con alto valor nutricional y potencial farmacológico. La mayoría de los estudios de este producto se han centrado en las propiedades de la miel producida por Apis mellifera, que se ha utilizado en medicina alternativa, destacando por sus actividades antioxidantes, antimicrobianas y antiinflamatorias, entre otras. En este trabajo, se identificó el origen floral, la concentración de proteína soluble, los compuestos fenólicos y la actividad antioxidante y quelante de metales de las mieles producidas por Melipona beecheii y Frieseomelitta nigra, originarias de San Marcos, comunidad de Tenosique en Tabasco, México. Los resultados muestran que la miel producida por F. nigra es de origen polifloral derivada principalmente de la especie Piper sp., aff. Brosimum, Asteraceae, Ziziphus sp., Haematoxylum campechianum, mientras que la producida porM. beecheii fue monofloral (Eugenia sp.). La miel de F. nigra presentó mayor concentración de compuestos fenólicos y mayor efectividad para atrapar los radicales superóxido y DPPH, además de un mejor potencial de quelación del cobre. Por su parte, la miel de M. beecheii presentó mayor capacidad de captación de los radicales ABTS y quelación del hierro; mientras que la capacidad de absorción del radical hidroxilo fue similar para ambas mieles. Este trabajo resalta la importancia de contar con análisis palinológicos y bioquímicos sobre las mieles de las abejas nativas sin aguijón por el potencial terapéutico que tienen y de las cuales, en el caso de algunas especies, no se tiene información.

Abstract Pests and inadequate post-harvest handling has led to losses in horticultural products, therefore the development and production of edible biodegradable films has been sought as an alternative in recent years. These edible films are made with materials such as carbohydrates, proteins, or lipids, with physical and mechanical characteristics similar to the non-degradable packaging, but with the advantage of having a bioactive function as barriers; by adding vegetable extracts, edible biodegradable films may exert antimicrobial activity, protection against UV and visible light, against carriers of antioxidants and/or dyes, along with improving the visual characteristics of the product. Because of these attributes, edible biodegradable films have been referred to as “Intelligent films”, since considerable progress has been observed in their elaboration, such as the presence of colorful sensors capable of detecting chemical changes and the presence of microorganisms in foods, revealing the state in which they are optimal and even if they are or not in an adequate state for consumption. The objective of this work is to make a summary of various research and current trends in the study and development of edible films and coatings, emphasizing their application in the horticultural chain and their effect on fresh and minimally processed foods.

Resumen Debido a las pérdidas en productos hortofrutícolas por plagas y manejo postcosecha inadecuado, en los últimos años se ha buscado el desarrollo y la producción de películas comestibles biodegradables como una forma de protección. Estas películas comestibles están hechas con materiales como carbohidratos, proteínas o lípidos, con características físicas y mecánicas similares a los envases no degradables, pero con la ventaja de funcionar como barreras bioactivas, ya que, mediante la adición de extractos vegetales, pueden presentar actividad antimicrobiana, protección contra la luz UV y visible, servir como acarreadores de antioxidantes y/o colorantes, mejorando con esto las características visuales del producto. Debido a estos atributos, han sido denominadas "películas inteligentes", ya que se ha observado un progreso considerable en su elaboración, como la presencia de sensores coloridos capaces de detectar cambios químicos y la presencia de microorganismos en los alimentos, mostrando si son o no, óptimos para el consumo. El objetivo de este trabajo es hacer una síntesis de diversas investigaciones, así como las tendencias recientes en el estudio y desarrollo de películas y recubrimientos comestibles, con énfasis en su aplicación a la cadena hortofrutícola y su efecto sobre productos frescos y mínimamente procesados.

Inga paterno is a tree legume present in various states of Mexico whose sheath is consumed in someplaces as a fruit due seed coat is sweet (Aryl). Seeds are not commonly consumed and there are few studies about its composition. The physical characteristics, nutritional and non-nutritional composition of Inga paterno seeds from México State and Puebla were analyzed. The seeds showed a significant proportion of protein and lipid. The oil from the seeds showed higher proportion of palmitic acid. Non-nutritional compounds such as phenolics, tannins, phytates, saponins and trypsin inhibitors were quantified. The seeds of the two sources of origin showed no statistically significant difference in their physical, chemical and non-nutritional characteristics; however, unlike other legumes, they exhibit high saponins content and high inhibitory trypsin activity.

Inga paterno es una leguminosa arbórea, que crece varios estados de México. La vaina se consume como fruto, debido a la cubierta dulce (Arilo) de la semilla. Ésta última, no es comúnmente consumida. Las características físicas, composición nutricional y el contenido de compuestos no nutricionales presentes en las semillas de Inga paterno provenientes de los Estados de México y Puebla fueron analizados, mostrando que las semillas son de 1.6 y 1.9 cm largo y 0.9 y 1.08 cm de ancho. Los componentes químicos principales son: proteína (20.42 y 21.59 g/100 g), carbohidratos (28.99 y 36.15 g/100 g), lípidos (9.62 y 8.55 g/100 g) para las procedentes de Ozumba y Tochimilco, respectivamente. Los aceites de las semillas de Inga paterno presentaron una proporción importante de ácido palmítico, así como ácidos 7-octadecanoico, oleico, linoleico y alfa linolénico. Se cuantificaron los compuestos no nutricionales como fenólicos (0.55 y 0.54 mg eq. de ácido gálico/g), taninos (1.46 y 1.51 mg eq. de (+)-catequina/g), fitatos (2.66 y 2.04 mg de ácido fítico/g), saponinas (32.35 y 33.38 mg de diosgenina/g) e inhibidores de tripsina (311.97 y 351.21 mg de tripsina pura inhibida/g de muestra). Ambas semillas analizadas no presentaron diferencia estadísticamente significativa en sus características físicas, químicas y no nutricionales; sin embargo, éstas presentan una elevada actividad inhibitoria de tripsina comparada con otras leguminosas.

Recentemente, existe um crescente interesse na atividade antioxidante e na capacidade de melhora da saúde da palma forrageira. A capacidade antioxidante das polpas dos frutos da palma forrageira foi avaliada anteriormente. Neste trabalho, compostos fenólicos, flavonoides e taninos da casca e sementes de quatro cultivares da palma forrageira foram examinados, assim como a sua capacidade antioxidante. Os taninos foram os principais compostos fenólicos nas sementes da palma forrageira, representando quase 50% de todos os cultivares. A análise de variância revelou que a maturação, o cultivar e sua interação tiveram um efeito altamente significativo sobre o conteúdo dos fenóis totais, taninos e flavonoides da pele da palma forrageira. Em sementes, apenas o estágio de maturação e a interação (estágio de maturação x cultivar) foram significativos em fenólicos totais e taninos. O teor de flavonoides de sementes não foi afetado por nenhum dos fatores ou suas interações. A capacidade antioxidante foi maior na pele do que nas sementes. Geralmente, as frutas com casca verde-clara ou amarelo-marrom apresentam maior atividade antirradical e maior valor de capacidade antioxidante equivalente a Trolox (TEAC), quando comparadas com os frutos vermelho-púrpura. De fato, os subprodutos da palma forrageira podem ser explorados como uma fonte boa e barata de antioxidantes naturais.

Recently, an increased interest in antioxidant activity and health-improving capacity of cactus pear has been registered. The antioxidant capacity of the pulp of cactus-pear fruits has been previously assessed. In this work, total phenolics, flavonoids and tannins of peel and seeds of four cactus pear cultivars were examined as well as their antioxidant capacity. Tannins were the major phenolics in cactus pear seeds accounting for almost fifty percent for all cultivars. Analysis of variance revealed that ripeness, cultivar, and its interaction had highly significant effect on the total phenolics, tannin, and flavonoid contents of cactus pear peel. With regard to the seeds, only the stage of ripeness and interaction (ripeness stage x cultivar) were significant on total phenolics and tannins contents. The flavonoid content in seeds was not affected by any of the factors or their interactions. The antioxidant capacity was higher in the peel than in the seeds. Generally, fruits with light-green or yellow-brown peel have higher antiradical activity and Trolox equivalent antioxidant capacity (TEAC) values compared with those with red-purple peel. Cactus pear by-products can indeed be exploited as a good and cheap source of natural antioxidants.