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The influence of elevated temperatures and composition on the water activity of egg powders
Author(s) -
PérezReyes Marco E.,
Tang Juming,
Zhu MeiJun,
BarbosaCánovas Gustavo V.
Publication year - 2021
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/jfpp.15269
Subject(s) - yolk , water activity , egg white , food science , water content , moisture , sorption , composition (language) , chemistry , adsorption , organic chemistry , linguistics , philosophy , geotechnical engineering , engineering
This study aimed to investigate water activity ( a w ) changes in different egg powders (egg white, egg yolk, and whole egg) as influenced by temperature between 20°C and 80°C. A high‐temperature test cell was used to measure the a w in egg powders of different moisture contents (2 to 30% wet basis) during heating in a closed environment. Then, the net isosteric heat of sorption ( q st ) of the egg powders was calculated. The q st values were used in the Clausius–Clapeyron equation to generate the isotherms of the egg powders at 40°C and 80°C. The results showed that at fixed moisture content and temperature, egg yolk powder had higher a w than whole egg and egg white powders. In addition, a w of the three egg powders in closed containers all increased with temperature. Egg white powder had stronger binding capacity to water, as reflected by the higher q st , compared to the other two egg powders. Practical applications An important determinant for the survival of microorganisms during thermal treatments is food water activity ( a w ), which changes with temperature. Currently, there is no scientific data regarding a w changes in egg powders at elevated temperatures. Therefore, this study aimed to determine the a w changes in egg powders as a function of temperature and composition. Data produced by this study regarding a w changes provide useful information for designing effective heat treatments to control pathogens in egg powders. The isosteric data should also help estimate the energy efficiency of egg powder drying operations.