Pulse method for determining thermo physical characteristics of fruits

Abstract

Background. The urgency of a rapid method for the determination of thermo physical parameters of fruits and vegetables is obvious, since it affects the effectiveness of both storage and processing of plant materials. From the thermal properties of fruits and vegetables depends the speed of their cooling or heating, thus increasing energy consumption for these processes.
The aim of the study is application of non-stationary pulse rapid method of measuring thermo physical parameters of fruit of apples and pears during cooling and freezing.
Material and methods. Objects of research are fruit of the apples Golden Delouses (Bakhchisarai district, Crimea, Ukraine) and pear varieties William’s (Greece). Pulse method is non-destructive determination of accelerated thermal characteristics using non-stationary device BI-T021. Thus there is a unilateral creation of a short heat pulse at the sample surface of raw fruits and registration of temperature changes on the surface.
Results. The use of microprocessor device BI-T021 enables one experiment to determine the thermal characteristics of the sample fruits. Thermal conductivity and diffusivity depends on two factors: humidity and temperature. These indicators have been defined by heating, cooling and freezing samples of apples and pears in the temperature range 265–333 K. When frozen fruits change their heat capacity, heat diffusivity, thermal conductivity, density. The results on thermal conductivity correlate with the literature [1; 3; 15].
Conclusion. The advantages of pulsed rapid method using a microprocessor device BI-T021 are the simplicity, speed (4 min) and the complexity of determining the thermal characteristics of fruit for example apples Golden Delouses sort and pears William’s, whose values are required for efficient storage and freezing plant material.