Inulin-type fructans are the most studied prebiotic compounds because of their broad range of health benefits. In particular, plants of the Agave genus are rich in fructans. Agave-derived fructans have a branched structure with both β-(2→1) and β-(2→6) linked fructosyl chains attached to the sucrose start unit with a degree of polymerization (DP) of up to 80 fructose units. The objective of this work was to assess the prebiotic potential of three Agave angustifolia Haw fructan fractions (AFF) with different degrees of polymerization. The three fructan fractions were extracted from the agave stem by lixiviation and then purified by ultrafiltration and ion exchange chromatography: AFF1, AFF2 and AFF3 with high (3-60 fructose units), medium (2-40) and low (2-22) DP, respectively. The fructan profile was determined with high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), which confirmed a branched fructan structure. Structural elucidation was performed by Fourier Transform Infra-Red 12661Spectroscopy. The AFF spectrum shows characteristic fructan bands. The prebiotic effect of these fractions was assessed in vitro through fermentation by Bifidobacterium and Lactobacillus strains. Four growth patterns were observed. Some bacteria did not grow with any of the AFF, while other strains grew with only AFF3. Some bacteria grew according to the molecular weight of the AFF and some grew indistinctly with the three fructan fractions.

Caracterización morfométrica de estructuras florales de Tagetes erecta L. y Tagetes patula L. (Asteraceae) utilizando análisis digital de imágenes y dimensión fractal RESUMENLas flores Tagetes erecta L. y Tagetes patula L. tienen usos ornamentales en México, y también algunas industrias las utilizan en la coloración de carne. El género Tagetes presenta especies y variedades con diferentes colores y tonalidades en sus flores. Por lo que, una forma de distinción rápida y objetiva de estas variedades sería útil para la industria. En este trabajo se desarrolló un método para distinguir y caracterizar la diversidad en dos variedades de T. erecta y T. patula a través de la caracterización de las estructuras florales, utilizando técnicas de análisis digital de imágenes y análisis fractal. Para esto, se capturaron imágenes de lígulas y capítulos florales, que posteriormente fueron binarizadas para obtener imágenes de objetos separados (lígulas y capítulos florales). El análisis de estas imágenes se realizó determinando diferentes parámetros morfométricos, tales como perímetro, área proyectada, longitud máxima, factor de forma y compacidad. Adicionalmente, se determinó la dimensión fractal de contorno, de perímetro y de área. Los resultados mostraron que la dimensión fractal y el factor de forma son los parámetros que detectan con mayor sensibilidad las diferencias entre lígulas y entre capítulos florales, por lo que se proponen como parámetro adecuados para caracterizar estructuras florales. Palabras clave:Tagetes erecta, T. patula, estructuras florales, análisis digital de imágenes, análisis fractal. ABSTRACTTagetes erecta L. and Tagetes patula L. flowers have ornamental uses in Mexico, but also some industries used in the coloring of meat. The genus Tagetes presents species and varieties with different colors and shades in their flowers. Therefore a rapid and objective form of distinction of these varieties would be useful for the industry. In this research was developed a method to distinguish and characterize the diversity in two varieties of the T. erecta and T. patula through the characterization of the floral structures, using techniques of digital image analysis and fractal analysis. Images of ligules and flower heads were captured and binarized to produce images of separate objects (ligules and flower heads). The analysis of these images was performed by determining different morphometric parameters such as perimeter, projected area, maximum length, shape factor and compactness. Additionally, the boundary fractal dimension, perimeter fractal dimension and area fractal dimension were determined. The results showed that the fractal dimension and form factor were the parameters in petals and flower head with higher sensitivity to detect differences between and among varieties and so are proposed as suitable parameter to characterize floral structures.