ABSTRACT The consumption of quinoa (Chenopodium quinoa Willd.) has been steadily increasing due to its high nutritional value and health benefits associated with its high antioxidant capacity. The objective of this study was to determine the contents of dietary fiber, polyphenols, flavonoids and isoflavones, and how they contribute to the antioxidant and antimicrobial activity of six ecotypes of quinoa cultivated in three different zones of Chile. The ecotypes studied were: Ancovinto and Cancosa (Northern zone), Cáhuil and Faro (Central zone), and Regalona and Villarrica (Southern zone). The results indicate that all Chilean quinoa ecotypes could be considered as good sources of dietary fiber (12.23 g 100 g-1 dry matter) and polyphenols (161.32 mg Gallic Acid Equivalents (GAE) 100 g-1 dry matter). The North and Central ecotypes exhibited the highest isoflavone concentration. The Northern Cancosa was the ecotype that showed the highest flavonoid content (211.06 mg Catechin Equivalents (CAE) 100 g-1 dry matter). Based on the ORAC (Oxygen Radical Absorbance Capacity) assay, Ancovinto, Cancosa and Faro presented the highest antioxidant capacity (67.6 mmol Trolox Equivalents (TE) 100 g-1 dry matter). Regarding antimicrobial activity, Regalona ecotype showed the best performance against Saccharomyces cerevisiae and Listeria innocua. The bioactive compounds found in this study add new knowledge to the antioxidant and antimicrobial activity of Chilean quinoa seeds.

RESUMEN El consumo de quinua (Chenopodium quinoa Willd.) está aumentando debido a su valor nutricional y beneficios para la salud relacionados con su capacidad antioxidante. El objetivo de presente estudio fue determinar los contenidos de fibra dietética, polifenoles, flavonoides e isoflavonas, y cómo estos compuestos contribuyen a la actividad antioxidante y antimicrobiana de seis ecotipos de quinua cultivados en tres zonas de Chile. Las muestras de quinua de la zona Norte se denominan Ancovinto y Cancosa, de la zona Centro se llaman Cáhuil y Faro, y de la zona Sur se denominan Regalona y Villarrica. Los resultados mostraron que todos los ecotipos de quinua chilena pueden considerarse buena fuente de fibra dietética (12,23 g 100 g-1 materia seca) y de polifenoles (161,32 mg de Equivalentes de Acido Gálico (EAG) 100 g-1 materia seca). Los ecotipos de la zona Norte y Centro mostraron la mayor concentración de isoflavonas. El ecotipo Cancosa, de la zona Norte, fue el que mostró el mayor contenido de flavonoides (211,06 mg Equivalentes de Catequina (ECA) 100 g-1 materia seca). Basado en el ensayo ORAC (del inglés Oxigen Radical Absorbance Capacity), los ecotipos Ancovinto, Cancosa y Faro, presentaron en promedio la mayor capacidad antioxidante (67,6 mmol de Equivalentes Trolox (ET) 100 g-1 materia seca). El ecotipo Regalona mostró la más alta actividad antimicrobiana frente a Saccharomyces cerevisiae y Listeria innocua. Los compuestos bioactivos encontrados en este estudio aportan nuevos conocimientos a la actividad antioxidante y antimicrobiana de las semillas de quinua chilena.

In this study, the effects of hot-air drying conditions on color, water holding capacity, and total phenolic content of dried apple were investigated using artificial neural network as an intelligent modeling system. After that, a genetic algorithm was used to optimize the drying conditions. Apples were dried at different temperatures (40, 60, and 80 °C) and at three air flow-rates (0.5, 1, and 1.5 m/s). Applying the leave-one-out cross validation methodology, simulated and experimental data were in good agreement presenting an error < 2.4 %. Quality index optimal values were found at 62.9 °C and 1.0 m/s using genetic algorithm.

O objetivo deste estudo foi avaliar o efeito da aplicação de altas pressões hidrostáticas (150, 250, 350, 450 e 550 MPa) aplicadas durante 5 minutos sobre a atividade antioxidante, concentração de polifenóis totais, cor, firmeza, taxa de reidratação e capacidade de retenção de água do gel de aloe vera armazenado durante 60 dias a 4 °C. As propriedades analisadas do gel pressurizado mostraram mudanças significativas depois de armazenadas. Para pressões de 550 Mpa, registrou-se o maior aumento de polifenóis totais. No entanto, observou-se uma diminuição da capacidade antioxidante em todas as amostras, em comparação com a amostra não tratada (p < 0,05). As alterações de cor foram menores para pressões entre 150 e 250 MPa. A aplicação de altas pressões hidrostáticas diminuiu a firmeza do gel, registrando-se o menor valor para 150 MPa (p < 0,05). Por outro lado, o tratamento sem pressão mostrou uma maior perda de firmeza, indicando que o tratamento por altas pressões conserva esta propriedade. A aplicação de altas pressões evidenciou modificações da matriz do alimento, avaliadas como taxa de reidratação e capacidade de retenção de água.

The aim of this study was to evaluate the influence of high hydrostatic pressure (150, 250, 350, 450, and 550 MPa), applied for 5 minutes, on antioxidant capacity, total phenolic content, color, firmness, rehydration ratio, and water holding capacity of aloe vera gel stored for 60 days at 4 °C. The analyzed properties of the pressurized gel showed significant changes after the storage period. The highest value of total phenolic content was found at 550 MPa. However, a decrease in the antioxidant capacity was observed for all pressurized gel samples when compared to the control sample (p < 0.05). The smallest changes in product color were observed at pressure levels between 150 and 250 MP. The application of high hydrostatic pressure resulted in lower gel firmness, and the lowest value was found at 150 MPa (p < 0.05). On the other hand, the untreated sample showed a greater decrease in firmness, indicating that high pressure processing preserves this property. The application of high hydrostatic pressure exhibited modifications in the food matrix, which were evaluated in terms of rehydration ratio and water holding capacity.