Determination of Drying Patterns of Radish Slabs under Different Drying Methods Using Hyperspectral Imaging Coupled with Multivariate Analysis.

Dongyoung Lee,Santosh Lohumi,Hyunmo Jung,Byoung-Kwan Cho,Seung Hyun Lee

doi:10.3390/foods9040484

Dongyoung Lee, Santosh Lohumi + Show 3 more

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https://doi.org/10.3390/foods9040484

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Abstract

Drying kinetics and the moisture distribution map of radish slabs under different drying methods (hot-air drying (HAD), microwave drying (MD), and hot-air and microwave combination drying (HMCD)) were determined and visualized by hyperspectral image (HSI) processing coupled with a partial least square regression (PLSR)-variable importance in projection (VIP) model, respectively. Page model was the most suitable in describing the experimental moisture loss data of radish slabs regardless of the drying method. Dielectric properties (DP, ) of radish slices decreased with the decrease in moisture content (MC) during MD, and the penetration depth of microwaves in radish was between 0.81 and 1.15 cm. The PLSR-VIP model developed with 38 optimal variables could result in the high prediction accuracies for both the calibration ( and ) and validation ( and ). In visualized drying patterns, the radish slabs dried by HAD had a higher moisture content at the center than at the edges; however, the samples dried by MD contained higher moisture content at the edges. The nearly uniform drying pattern of radish slabs under HMCD was observed in hyperspectral images. Drying uniformity of radish slabs could be improved by the combination drying method, which significantly reduces drying time.

Highlights

Radish is a popular root vegetable with high moisture content and good effect on digestion [1]It is processed into a variety of products such as dried, salted, pickled, and fermented products inAsia [2]
Studies on the measurement of Dielectric properties (DP) of agricultural products depending on temperature have been performed by several researchers; few studies have been conducted to measure the DP of agricultural products depending on moisture content (MC)
In order to overcome the inherent problems of Microwave drying (MD) and hot-air drying (HAD), a number of researchers have investigated the effect of hot-air and microwave combination drying (HMCD), and have reported that this combination drying method leads to a more effective drying process than individual MD or HAD methods [4]

Summary

Introduction

Radish is a popular root vegetable with high moisture content and good effect on digestion [1]It is processed into a variety of products such as dried, salted, pickled, and fermented products inAsia [2]. Radish is a popular root vegetable with high moisture content and good effect on digestion [1]. It is processed into a variety of products such as dried, salted, pickled, and fermented products in. Microwave drying (MD) as an alternative to hot-air drying (HAD) significantly improves the drying rate while maintaining the quality of dried food materials or agricultural products. In order to overcome the inherent problems of MD and HAD, a number of researchers have investigated the effect of hot-air and microwave combination drying (HMCD), and have reported that this combination drying method leads to a more effective drying process than individual MD or HAD methods [4]

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