Respiración De Frutas

Revista Amazónica de Investigación Alimentaria, v.2, nº 1, p. 27- 37 (2001)

Facultad de Ingeniería en Industrias Alimentarias UNAP, Iquitos-Perú ISSN: 000000

DETERMINACIÓN DEL CALOR DE RESPIRACIÓN DE FRUTAS POR EL MÉTODO DE TITULACIÓN
Juana Montes; Segundo Arévalo Facultad de Ingeniería en Industrias Alimentarias de la UNAP, Iquitos, Perú jemonda@hotmail.com

ABSTRACT

The respirationheating of fruits, specially in apples, was the principal objective of the present work by starting with a titration method. An alkaline solution of titration is used by this method where air exempt of CO2 is circulating through a drier to hold the fruit to be studied at a determined temperature. Then, it is bubbled by an alkaline solution where the absorption of the present CO2 happens. Adecreasing about the equivalence number (EN) of the solution occurs in the reaction of CO2 with the alkaline solution and this variation is equal to the equivalent number of CO2 that had such reaction. This equality permits to quantify the CO2 absorbed into a determined period of time. A system was necessary to build in order to get the mentioned objective. And such system consisted in setting theproduct in a drier which at the same time was installed into a small respiratory chamber where air circulates at a established temperature activated by a thermostat. A vacuum pump was used to renovate continually the existent air at the interior of the drier. The humidifying air is conducted through the drier and later bubbled in the pipes that are connected in series, containing the alkaline solution.A leak air test in the critic points of the equipment was done to measure about its veridical results as well as its grade of confidence. The test consists in simulating a defined quantity of CO2 into the drier and in verifying its recovery through the equivalent number of the basic solution between two titration—the recovered CO2 was about 91,2%. The heating respiratory values of the apples atroom temperature were determined with the system while it was working properly, and the results of the first test were:2483,8 kcal/(tn).(24h) to 26,55°C, the second: 2586,0 kcal/(tn). (24h) to 26,68°C and in the last test the value was: 2862,9kcal/(tn). (24h) to 26,73°C. The results indicate that as soon as the temperature augments, the heating respiratory value of the studied fruit also increaseswhile the fruit is between the ripe time and senescence moment; therefore a temperature reduction implies less fruit respiration, and that augments in such a way its storage time(useful life). Key Words: Respiration heat; CO2; NaOH; Equivalent Number; Fruits; Apple.

J. Montes; S. Arévalo

RESUMEN El presente trabajo tuvo por objetivo determinar el calor de respiración de frutas (manzanas)empleando el método de titulación. Este método emplea la titulación de solución alcalina, donde el aire exento de CO2 es circulado a través del desecador conteniendo la fruta a ser estudiada a una determinada temperatura. Enseguida es burbujeado a una solución alcalina donde ocurre la absorción de CO2 presente. En la reacción del CO2 con la solución alcalina, ocurre un decrecimiento del númeroequivalente (NE) de la solución, esta variación es igual al número equivalente al CO2 que reaccionó. La igualdad permite cuantificar el CO2 absorbido en un determinado período de tiempo. Para conseguir el objetivo en mención se construyó un sistema, donde el producto es colocado en un desecador y éste a su vez es instalado en el interior de una pequeña cámara de respiración, donde el aire circula a unatemperatura establecida por la acción de un termostato. Para renovar continuamente el aire existente en el interior del desecador se utilizó una bomba de vacío. El aire humidificado es conducido a través del desecador y posteriormente burbujeado en los tubos conectados en serie conteniendo la solución alcalina. Para medir el grado de confiabilidad del equipo y la veracidad de los resultados, se...