Health-promoting activities of edible seaweed extracts from Chilean coasts: assessment of antioxidant, anti-diabetic, anti-inflammatory and antimicrobial potential / Actividades promotoras de la salud de extractos de algas comestibles de las costas chilenas: evaluación del potencial antioxidante, antidiabético, antiinflamatorio y antimicrobiano

ABSTRACT The aim of this study was to evaluate the antioxidant, antidiabetic, anti-inflammatory and antimicrobial activities of three edible seaweed extracts from Chilean coasts: Pyropia orbicularis, Ulva spp, and Durvillaea antarctica. Seaweed extracts in methanol and 70% acetone were performed to evaluate antioxidant and antidiabetic activities, whereas 60% methanol was used to measure anti-inflammatory and antimicrobial activities. Acetone extracts from D. antarctica had the highest total phenolic content and consequently exhibited the strongest antioxidant activity, while methanol extract of this seaweed presented the highest α-glucosidase inhibition (IC50= 0.004 mg mL-1). In the tests against E. coli and Penicillium sp., the extracts obtained from Ulva spp. were the most effective and exhibited the maximum anti-inflammatory effect against phorbol 12-myristate 13-acetate irritant agent (61.8% inhibition) in mice. Results indicated that all evaluated Chilean seaweed extracts are promising candidates for application in functional foods and in the pharmaceutical industry.

RESUMEN El objetivo de este estudio fue evaluar las actividades antioxidantes, antidiabéticas, antiinflamatorias y antimicrobianas de los extractos de tres algas marinas comestibles de las costas Chilenas (Pyropia orbicularis, Ulva spp. y Durvillaea antarctica). Se realizaron extractos de algas marinas en metanol y acetona al 70% para evaluar las actividades antioxidantes y antidiabéticas, mientras que el metanol al 60% se usó para actividades antiinflamatorias y antimicrobianas. Los extractos de acetona de D. antarctica tuvieron el mayor contenido de fenoles totales (TPC) y, en consecuencia, exhibieron la mayor actividad antioxidante, mientras que el extracto metanólico de estas algas presentó la mayor inhibición de la α-glucosidasa (IC50= 0,004 mg mL-1). En las pruebas contra E. coli y Penicillium sp., los extractos obtenidos de Ulva spp., actuaron como los más efectivos y exhibieron el máximo efecto antiinflamatorio contra el agente irritante de forbol 12-miristato 13-acetato (TPA) (inhibición del 61,8%) en ratones. Por lo tanto, los resultados indican que todos los extractos de algas chilenas evaluados pueden ser candidatos prometedores para su aplicación en alimentos funcionales y en las industrias farmacéuticas.

Mathematical modeling of convective air drying of quinoa-supplemented feed for laboratory rats

Drying kinetics of quinoa-supplemented feed for laboratory rats during processing at 50, 60, 70, 80 and 90ºC was studied and modeled in this work. Desorption isotherm was obtained at 60ºC giving a monolayer moisture content of 0.04 g water/g d.m. The experimental drying curves showed that drying process took place only in the falling rate period. Several thin-layer drying equations available in the literature were evaluated based on determination coefficient (r²), sum squared errors (SSE) and Chi-square (χ2) statisticals. In comparison to the experimental moisture values, the values estimated with the Logarithmic model gave the best fit quality (r² >0.994, SSE < 0.00015 and χ2 < 0.00018), showing this equation could predict very accurately the drying time of rat feed under the operative conditions applied.