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Journal of Food Quality
Volume 2018, Article ID 1347513, 12 pages
https://doi.org/10.1155/2018/1347513
Research Article

Effect of Hot-Water Blanching Pretreatment on Drying Characteristics and Product Qualities for the Novel Integrated Freeze-Drying of Apple Slices

1School of Food Science, Nanjing Xiaozhuang University, Nanjing 211171, China
2Key Laboratory of Modern Agricultural Equipment, Ministry of Agriculture, Nanjing 210014, China
3Nanjing Research Institute for Agricultural Mechanization, Ministry of Agriculture, Nanjing 210014, China

Correspondence should be addressed to Hai-ou Wang; moc.361@8791ohw

Received 14 August 2017; Revised 16 December 2017; Accepted 8 January 2018; Published 1 February 2018

Academic Editor: Hong-Wei Xiao

Copyright © 2018 Hai-ou Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The effect of hot-water blanching (HWB) on drying characteristics and product qualities of dried apple slices with the novel integrated freeze-drying (NIFD) process was investigated by comparing with 3 different FD methods. Compared with the NIFD process without HWB pretreatment (VF-FD), the NIFD process with HWB pretreatment (HWB-VF-FD) resulted in a significantly higher mass loss and more sufficient freezing in vacuum-frozen samples, significantly higher rehydration ratio (RR), higher shrinkage ratio (SR), smaller Vitamin C () content and lower hardness and better apparent shape in freeze-dried samples, and fewer change to the color of the dried or rehydrated samples (). Compared with the conventional FD process with HWB pretreatment (HWB-PF-FD), HWB-VF-FD cost significantly less processing time and FD time and obtained significantly higher RR (), almost the equivalent SR, content, and hardness, and similar appearance in dried samples. The microstructure of apple cell tissues was analyzed by transmission electron microscopy and scanning electron microscopy to interpret the above differences in drying characteristics and product qualities. The results suggested that the NIFD process of apple slices with HWB pretreatment was a promising alternative method to decrease drying time, achieve similar product quality, and simplify the process steps of the conventional FD technology.