Heat and Mass Transfer, and Volume Variations in Banana Slices during Convective Hot Air Drying: An Experimental Analysis

Raimundo P Farias,Antonio G B Lima,Leonardo P L Silva,Ivonete B Santos,José J S Nascimento,Wilton P Silva,Guilherme L Oliveira Neto,João E F Carmo,Ricardo S Gomez

doi:10.3390/agriculture10100423

Abstract

Bananas are some of the most consumed fruits throughout the world, providing metabolizable calories and vitamins for humans, along with many other benefits. However, this fruit tends to be easily degraded by microorganisms and other chemical agents because of the high moisture content. Considering the importance, this work focuses on an experimental study regarding banana fruit drying. For such purpose, whole bananas were hand-peeled and sliced longitudinally and then dried by a hot air circulation oven with air temperatures of 40 °C, 50 °C, 60 °C and 70 °C. Measurements of mass, temperature, and dimensions of the sample were done during the drying process. Results of drying, heating, and shrinkage (volume and surface area) kinetics are presented and analyzed. The study revealed that the drying air temperature significantly affected moisture removal, heating, and dimensions’ variation rates, as well as quality of banana fruit. The drying carried out with higher temperature and lower relative humidity of the air gave rise to higher rates of drying, heating and variation of dimensions, and shorter drying time of the product.

Highlights

Fruits are capable of providing flavor and diversities to the human diet, and are important and indispensable sources of vitamins, minerals, fiber, and carbohydrates
Due to the moisture content being plotted in dimensionless form, the results are independent from each other of the initial moisture content and balance of the banana in each experimental condition
The drying process of banana slices was analyzed with one drying mechanism

Summary

Introduction

Fruits are capable of providing flavor and diversities to the human diet, and are important and indispensable sources of vitamins, minerals, fiber, and carbohydrates. Because of that nutritional characteristics, and coupled with population growth, the production and consumption of processed fruits are progressively increasing. Bananas are an important source of human food mainly due to their mineral and vitamin contents and the provided calorific value (energy). It contains dopamine and various phenolic compounds, for example, catechin in its composition without the intakes of fats and cholesterol [1]. Due to nutritional and aromatic characteristics, bananas have received considerable attention from researchers, which identified more than 350 compounds present in the fruit. Despite being harvested in quantities and qualities due to the practically equal seasonal season throughout the year, the fruit must be consumed within a maximum period of up to 25 days after harvest

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Results

Conclusion