Optimization of Microwave Coupled Hot Air Drying for Chinese Yam Using Response Surface Methodology

Hanyang Wang,Haiming Yu,Dan Liu,Jun Li,Donghai Wang

doi:10.3390/pr7100745

Abstract

The effect of microwave coupled hot air drying on rehydration ratio (RR) and total sugar content (TSC) of Chinese yam was investigated. Single factor test and response surface methodology were used for process parameter optimization with hot air temperature, hot air velocity, slice thickness, and microwave power density as variables and RR and TSC of dried products as responses. The effect of variables on RR followed the order: slice thickness > hot air temperature > microwave power density > hot air velocity. The effect of variables on TSC followed the order: slice thickness > microwave power density > hot air velocity > hot air temperature. The optimized process parameters were hot air velocity of 2.5 m/s, hot air temperature of 61.7 °C, slice thickness of 8.5 mm, and microwave power density of 5.9 W/g. Under the optimal conditions, the predicted values of RR and TSC were 1.90 g/g and 5.74 g/100 g, respectively, which is very close to corresponding actual values (1.83 g/g and 5.72 g/100 g). The desirability of 0.913 further validated the effectiveness of the model. The findings from this work may apply to other agricultural products.

Highlights

Chinese yam is an edible food and an herbal medicinal ingredient [1,2]
Chinese yam gets molded during room temperature storage due to high moisture content, which causes a large amount of nutritional ingredients to be lost and lowers its quality and dietary properties [5,6]
The optimal conditions of microwave coupled with hot air (MWHA) drying for Chinese yam slices was obtained using

Summary

Introduction

Chinese yam is an edible food and an herbal medicinal ingredient [1,2]. Chinese yam contains starch, protein, polysaccharides, dopamine, flavonoids, amino acids, allantoin, trace elements, and other active ingredients. Same as other vegetables and fruits, fresh Chinese yam is damaged during the harvest and transportation because of its crispness and high moisture content, which shortens its shelf life. Chinese yam gets molded during room temperature storage due to high moisture content, which causes a large amount of nutritional ingredients to be lost and lowers its quality and dietary properties [5,6]. To address these issues, drying is usually used to reduce the moisture content lower than a certain threshold value [7]. As a result, choosing a proper method is very important for drying of Chinese yam

Objectives

Methods

Conclusion