Scanning electron microscopic study of microstructure of gala apples during hot air drying

Karunasena, H. C. P. and Hesami, P. and Senadeera, W. and Gu, Y. T. and Brown, R. J. and Oloyede, A. (2014) Scanning electron microscopic study of microstructure of gala apples during hot air drying. Drying Technology, 32 (4). pp. 455-468. ISSN 0737-3937


Microscopic changes that occur in plant food materials during drying significantly influence the macroscopic properties and quality factors of the dried food materials. It is critical to study the microstructure to understand the underlying cellular mechanisms to improve the performance of food drying techniques. However, there is limited research on such microstructural changes of plant food material during drying. In this work, Gala apple parenchyma tissue samples were studied using a scanning electron microscope for gradual microstructural changes as affected by temperature, time, and moisture content during hot air drying at two drying temperatures: 57 and 70C. For fresh samples, the average cellular parameter values were as follows: cell area, 20,000um2; ferret diameter, 160um; perimeter, 600um; roundness, 0.76;elongation, 1.45; and compactness, 0.84. During drying, a higher degree of cell shrinkage was observed with cell wall warping and an increase in intercellular space. However, no significant cell wall breakage was observed. The overall reductions in cell area, ferret diameter, and perimeter were about 60, 40, and 30%. The cell roundness and elongation showed overall increments of about 5% and the compactness remained unchanged. Throughout the drying cycle, cellular deformations were mainly influenced by the moisture content. During the initial and intermediate stages of drying, cellular deformations were also positively influenced by the drying temperature and the effect was reversed at the final stages of drying, which provides clues regarding case hardening of the material.

Statistics for USQ ePrint 30546
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 07 Feb 2017 04:48
Last Modified: 20 Feb 2017 04:35
Uncontrolled Keywords: cell deformations; food drying; microstructure; plant cells; scanning electron microscope; shrinkage
Fields of Research : 09 Engineering > 0908 Food Sciences > 090802 Food Engineering
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970109 Expanding Knowledge in Engineering
Identification Number or DOI: 10.1080/07373937.2013.837479

Actions (login required)

View Item Archive Repository Staff Only