Freezing characteristics and relative permittivity of rice flour gel in pulsed electric field assisted freezing

Roujia Zhang; Fuyuan Ding; Yang Zhang; Chenguang Zhou; Wen Zhang; Jiyong Shi; Xiaobo Zou; Jianbo Xiao

doi:10.1016/j.foodchem.2021.131449

Freezing characteristics and relative permittivity of rice flour gel in pulsed electric field assisted freezing

Food Chem. 2022 Mar 30;373(Pt A):131449. doi: 10.1016/j.foodchem.2021.131449. Epub 2021 Oct 21.

Authors

Roujia Zhang¹, Fuyuan Ding¹, Yang Zhang¹, Chenguang Zhou², Wen Zhang¹, Jiyong Shi³, Xiaobo Zou⁴, Jianbo Xiao⁵

Affiliations

¹ Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
² Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; China-Canada Joint Lab of Food Nutrition and Health (Beijing), Beijing Technology and Business University, Beijing 100048, China.
³ Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China. Electronic address: Shi_jiyong@ujs.edu.cn.
⁴ Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China. Electronic address: zou_xiaobo@ujs.edu.cn.
⁵ International Research Center for Food Nutrition and Safety, Jiangsu University, Zhenjiang 212013, China; Department of Analytical Chemistry and Food Science, Faculty of Food Science and Technology, University of Vigo, Ourense Campus, E-32004 Ourense, Spain.

PMID: 34715631
DOI: 10.1016/j.foodchem.2021.131449

Abstract

This study investigated the effect of pulsed electric field assisted freezing treatment on the freezing characteristics of rice flour gel under output voltages varying from 0 to 25 kV. The results indicated that by applying a pulsed electric field, the phase change time decreased. Scanning electron microscopy images indicated that pulsed electric field treatment led to the formation of rounder and smaller ice crystals. For further understanding and quantifying the interaction between rice flour gel and a pulsed electric field, the relative permittivity of rice flour gel with and without the addition of salt was measured between 100 and 3100 kHz and -20 and 20 °C. Relative permittivity increased with decreasing frequency or increasing temperature, and sharp variation was observed during the phase transition period. In addition, salt was proved to be an effective additive for increasing relative permittivity.

Keywords: Freezing rate; Microstructure; Phase change; Pulsed electric field; Relative permittivity; Rice.

MeSH terms

Electricity
Flour*
Freezing
Oryza*
Temperature