Application of a MOGA Algorithm and ANN in the Optimization of Apple Drying and Rehydration Processes

Radosław Winiczenko,Krzysztof Górnicki,Agnieszka Kaleta

doi:10.3390/pr9081415

Abstract

The aim of the study was to estimate the optimal parameters of apple drying and the rehydration temperature of the obtained dried apple. Conducting both processes under such conditions is aimed at restoring the rehydrated apple to the raw material properties. The obtained drying parameters allow the drying process to be carried out in a short drying time (DT) and at low energy consumption (EC). The effect of air velocity (vd), drying temperature (Td), characteristic dimension (CD), and rehydration temperature (Tr) on rehydrated apple quality was studied. Quality parameters of the rehydrated apple as: color change (CC), mass gain ratio (MG), solid loss ratio (SL), volume gain ratio (VG) together with DT and EC were taken into consideration. The artificial neural network was used for modeling of rehydrated apple quality parameters, DT, and EC. A multi-objective genetic algorithm was developed in order to optimize parameters of the drying and rehydration processes. The simultaneous minimization of CC, SL, DT, EC, and the maximization of MG and VG were considered with the following drying and rehydration processes parameters: Td: 50–70 °C, vd: 0.01–2 m/s, Tr: 20–70 °C. The best solution has been found at drying temperature 56.1 °C, air velocity 1.3 m/s, characteristic dimension 2.0 mm, and rehydration temperature 59.2 °C. This apple drying and rehydration resulted in MG = 3.51, SL = 0.57, VG = 4.77, CC = 11.2, DT = 5.4 h, EC = 159.8 GJ/kg. The parameters of apple drying and rehydration processes can be recommended for the industry application.

Highlights

Apples are one of the basic horticultural products and apple plantations are present all over the world
Solution ID 11 indicates the following drying and rehydration parameters: Td = 53.8 ◦C, vd = 1.54 m/s, characteristic dimension (CD) = 1.5 mm, and Tr = 48.4 ◦C, and the obtained rehydrated product shows color change (CC) = 13.96, drying time (DT) = 6.0 h, mass gain ratio (MG) = 3.55, solid loss ratio (SL) = 0.53, volume gain ratio (VG) = 4.78, energy consumption (EC) = 235.2 GJ/kg (CC 49.60% and 20.0% higher, DT 26.8% and 9.5% higher, MG 1.0% lower and 1.1% higher, SL 19.4% higher and 7.0% lower, VG 0.3% lower and 0.2% higher, and EC 41.0% and 32.1% higher than the minimum or maximum values, respectively, and the value for ID10)
The rehydrated product obtained in such conditions shows CC = 10.39, DT = 4.67 h, MG = 3.46, SL = 0.58, VG = 4.75, EC = 216.1 GJ/kg (CC 32.3% higher and 7.5% lower, DT 5.1% higher and 16.2% lower, MG 3.5% and 1.4% lower, SL 26.5% and 2.4% higher, VG 0.8% and 0.3% lower, and EC 35.8% and 26.0% higher than the minimum or maximum values, respectively, and the value for ID10)

Summary

Introduction

Apples are one of the basic horticultural products and apple plantations are present all over the world. Poland is a significant global producer of these fruits. Apples are low caloric fruits and play a significant role in the human diet. They typically contain about 86% of H2O, 12–14% of carbohydrate, 0.3% of protein, 0.2% of lipids, 2% of dietary fiber and many very important minerals (Ca, Mg, K). Apples may help in reducing the effect of asthma and cholesterol levels [1,2,3]. Dried apples (instead of fresh) may be used in many processed or ready-to-eat foods due to advantages such as the convenience of transportation, storage, preparation, and use. Dehydrated apples sometimes are rehydrated before consumption or further processing

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Results

Conclusion