RESUMEN La pectina es un producto tecnológicamente funcional por sus propiedades reológicas. En Colombia en el año 2010 se importaron aproximadamente 195 toneladas de pectina y su demanda sigue en aumento. El objetivo del estudio fue extraer y caracterizar la pectina obtenida de la cáscara de mango de azúcar maduro. El aislamiento del material se realizó mediante hidrolisis ácida, con ácido clorhídrico 0,5 N y alcohol etílico al 96% para su precipitación y purificación. Para la extracción se utilizó un arreglo factorial 3 2 , evaluando los factores pH y temperatura, con los niveles 1, 2, 3 y 80, 90, 100 ºC respectivamente, estableciendo como variable fija un tiempo de 60 minutos. Se dispuso de 27 unidades experimentales equivalentes a 550 g de cáscara de mango de azúcar maduro seca y molida. Los mejores resultados para la obtención de la pectina fueron pH 1 y temperatura 100 ºC, reportando un rendimiento de 15,257 ± 0,04%. La pectina obtenida presentó las siguientes características: humedad 4,510 ± 0,80%, cenizas 1,351 ± 0,07%, alcalinidad de las cenizas 1,711 ± 1,13%, acidez libre 0,859 ± 0,01 mEq de carboxilo libre/g, peso equivalente 2326,420 ± 54,11 mg/ mEq, contenido de metoxilo 11,801 ± 0,03%, grado de esterificación 81,688 ± 024%, contenido de ácido anhidrogalacturónico 82,380 ± 0,17%, el análisis de espectrofotometría infrarrojo, mostró los picos de grupos funcionales, característicos de la pectina obtenida y su similitud frente a una pectina estándar. El material estudiado es fuente potencial de pectina de calidad. ABSTRACT Pectin is a functional technology product by her rheological characteristics. In 2010 in Colombia, there were imported approximately 195 tons and its demand is increasing. The main goal of this research was to extract and characterize the pectin from ripe sugar mango peel. The isolation of pectin material was accomplished by acid hydrolysis, with hydrochloric acid to 0.5 N and ethyl alcohol to 96 % for precipitation and purification. For the extraction of pectin factorial arrangement 32 was used where the two factors evaluated were: pH and temperature, which took the levels 1, 2, 3 and 80, 90, 100 respectively, in a constant time of 60 minutes. There were 27 experimental units equivalent to 550 g of ripe, dry and ground sugar mango peel. The results were evaluated and it was stated that ideal variables (pH 1 and temperature 100 ºC) allow to extract major quantity of pectin, bringing a performance of 15.257±0.04%. The obtained pectin presented the following characteristics: humidity content (4.510 ± 0.80%), ashes content (1.351± 0.07%), alkalinity of the ashes (1.711±1.13%), free acidity (0.859±0.01 mEq free / g carboxyl), equivalent weight (2326.420±54.11 mg / mEq), methoxyl (11,801 ±0.03%), degree of esterification (81.688±024%), anhydrous acid content (82.380±0.17%) and the analysis by infrared spectrophotometry, showed the peaks of functional groups, typical of the obtained pectin and its similarity opposite to a standard pectin. The material studied is a potential source of quali...

Summtary. During a 36-hour period, the rate of absorpt:on of oxygen, respiration qtuotient, and rate of evolution of heat have been measured tusing seeds of Prosopis ju(liflora, Kochia scoparia, and Oxyriti digyna. The results obtained in pure water were compared with those obtained in dilute solutions of dinitrolphenol. The data appear to be reproducible to + 10 % at the end of the 36-hour period and are independent of the amount of seeds used, provided it was 0.05 g or less. For a given amount of oxygen absorbed, more heat was liberated when the seeds were in a dinitrophenol solution. The results permit an estimate to be made of the heat energy stored in oxidative phosphorylation.It is well known (3) that the germination of seeds is an exothermic process. Calvet and Prat (9) measured the rate of evolution of heat by germinating seeds. Dewez (4) has studied the heat evolution and water uptake of cotton seeds. The investigators used relatively large samples (0. -