(2013) Effects of extrusion process in snacks of oats-nixtamalized corn pericarp mixtures on dietary fiber content and functional properties, CyTA -Journal of Food, 11:sup1, 38-45, DOI: 10.1080/19476337.2012 The aim this work was to establish the best conditions to increase the soluble dietary fiber (SDF), evaluate the effect of extrusion on the SDF, and insoluble dietary fiber (IDF), in a snack obtained by extrusion, that serve as a source of calcium and DF, using mixtures of oat-corn pericarp. The corn pericarp was obtained from byproduct of nixtamalization process which contains water, calcium hydroxide, soluble solids, and pericarp. The studied parameters were temperature (120-1408C), moisture (200-400 g/kg), and corn pericarp (200-400 g/kg); the responses were expansion ratio, SDF, IDF, and water absorption index (WAI). The R 2 were 4 0.85 for all factors. The best conditions were temperature (1338C), moisture (230 g/kg), and corn pericarp (300 g/kg), with responses of 93.1 g/kg increase in SDF, 60 g/kg decrease of IDF, expansion of 1.26, WAI of 4.12 g sediment/g dry solid, and calcium content 4350 mg/kg.

ResumenEste estudio cuantifica el contenido de cobre en aguacate y su pH en ciruela, fresa, kiwi, mamey, mango, manzana, pera y plátano. También cobre en la enzima polifenoloxidasa y velocidad de obscurecimiento. El cobre se determinó mediante espectrofotometría de absorción atómica en muestras digeridas por vía húmeda. El aguacate tuvo más cobre en enzimas (0.059 mg) con mayor velocidad de obscurecimiento (0.751 s -1 ); la fresa tuvo la menor cantidad de cobre (0.016 mg) y la menor velocidad de reacción (0.115 s -1 ). Las frutas con pH más ácido tuvieron contenido medio de cobre en la enzima y el menor obscurecimiento. La pera y el plátano tuvieron velocidad de reacción (0.3) y pH similares pero contenidos diferentes de cobre. Los resultados permiten establecer una correlación directa entre el contenido de cobre en enzimas y la velocidad obscurecimiento. Palabras clave: absorción atómica, cobre, frutas, polifenoloxidasa, velocidad de obscurecimiento AbstractThis work quantifies the copper content in avocado and pH in, plum, strawberry, kiwi, mamey sapote, mango, apple, pear and banana. Copper and browning rate on enzymes of those fruits were also determined. Copper content was measured by atomic absorption spectrophotometry on samples digested by wet-chemical method. Avocados had the highest content of copper on enzymes (0.059 mg) with the highest browning rate (0.751 s -1 ) while strawberries had the lowest copper content (0.016 mg) and the lowest browning rate (0.115 s -1 ). Fruits with acid pH had acceptable copper content on the enzyme and a low browning rate. Pears and bananas had similar pH and browning rate (0.3) with different copper contents. The results do not allow establishing a direct relationship between copper content in enzymes and its browning rate.