Ingeniero en alimentos

R evista 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

Therespiration heating 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 CO2happens. A decreasing about the equivalence number (EN) of
the solution occurs in the reaction of CO2 w ith 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 insetting the product 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, containingthe 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 respiratoryvalues of the apples at room 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 thestudied fruit also increases while 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 derespiración 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 número equivalente (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 cámarade
respiración, donde el aire circula a una temperatura 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...