The antioxidant properties and the flavonoid composition of extracts of different hydrophobicity prepared from the entire edible flowers of Agave durangensis were evaluated. Separately, total extracts of tepals and anthers-pollen were analyzed in the same manner. The high performance liquid chromatography with photodiode array detection (HPLC-DAD) analysis revealed a total of eight flavonols (five quercetin glycosides and three kaempferol glycosides), varying in number and concentration in the different extracts. The total extracts of the entire flowers showed the highest flavonoid content (1210.4 µg/g dry extract) and the most complex flavonoid profile (eight compounds). All the extracts showed important antioxidant activity, which was not evidently associated with their flavonoid content. The total extracts of tepals showed the highest antioxidant properties (total antioxidant capacity, free radical scavenging activity, and iron reducing capacity: 30.2 mg ascorbic acid equivalents, EC 50 = 0.074 µg/mL, and IC 50 = 43.28 µg/mL, respectively). The flowers of A. durangensis represent an important source of antioxidant flavonols.Keywords: Agave durangensis; edible flowers; flavonoid profiles; antioxidant capacity; flavonol glycosides Se evaluaron las propiedades antioxidantes y composición fenólica de extractos de diferente hidrofobicidad de flores comestibles enteras de Agave durangensis. Separadamente, se analizaron extractos crudos de tépalos y anteras-polen. El análisis de HPLC-DAD reveló en total ocho flavonoles (cinco glicósidos de quercetina y tres glicósidos de canferol), que variaron en número y concentración en los extractos. Los extractos totales de las flores enteras tuvieron el contenido más alto de flavonoides (1210,4 µg/g extracto seco) y el perfil de flavonoides más complejo (ocho compuestos). Todos los extractos mostraron importante actividad antioxidante, no claramente asociada al contenido de flavonoides. Los extractos crudos de tépalos mostraron las propiedades antioxidantes más altas (capacidad antioxidante total, capacidad bloqueadora de radicales libres, y capacidad reductora de fierro: 30,2 mg de equivalentes de ácido ascórbico, EC 50 = 0,074 µg/mL, e IC 50 = 43,28 µg/mL, respectivamente). Las flores de A. durangensis representan una fuente importante de flavonoles antioxidantes.

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The aim of this work was to analyze the effect of spray drying conditions on the physical properties of pitaya juice powder using a 2 3 factorial design. Independent variables were inlet air temperature (150 and 180°C), feed flow rate (1.5 and 2 L/hr), and the amount of encapsulants (60 and 90%). The spray process was performed on pilot-scale spray dryer and maltodextrin/pectin combination was used as encapsulating material. Moisture content, yield, color, water adsorption, glass transition temperature, and morphology of pitaya juice powders were analyzed. Critical conditions of storage, at which the glass transition occurs were determined. Experimental results showed that all the individual factors had a significant effect on moisture content and color, however, yield was only affected by feed flow rate and percentage of encapsulants. Lower drying temperatures (150°C) favored higher yield of 59% and privileged red-violet color retention during spray drying. The GAB and Gordon-Taylor models gave good fit for the experimental data of adsorption isotherms and glass transition temperatures, respectively. Practical ApplicationsIn this work betalains with compounds including nutraceutical properties, which can be used as a dye, were encapsulated. The knowledge of the properties of natural products, with potential either as an additive or as a colorant, is of great significance for applications in both the food and pharmaceutical industry. The efficiency, color, morphology of powders, and properties influencing hygroscopicity, collapse, compression, and agglomeration were determined. These factors control the processability, handling properties, and the stability of pitaya powders.

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