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

Karunasena, H.C.P., Hesami, Parva, Senadeera, Wijitha, Gu, YuanTong, Brown, Richard J., & Oloyede, Adekunle (2014) Scanning electron microscopic study of microstructure of Gala apples during hot air drying. Drying Technology : An International Journal, 32(4), pp. 455-468.

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Microscopic changes occur in plant food materials during drying significantly influence the macroscopic properties and quality factors of the dried food materials. It is very critical to study microstructure to understand the underlying cellular mechanisms to improve performance of the food drying techniques. However, there is very limited research conducted 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 70 ℃. For fresh samples, the average cellular parameter values were; cell area: 20000 μm2, ferret diameter: 160 μm, perimeter: 600 μm, 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 increase in intercellular space. However, no significant cell wall breakage was observed. The overall reduction of 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 for case hardening of the material.

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12 citations in Web of Science®

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ID Code: 67482
Item Type: Journal Article
Refereed: Yes
Keywords: Food Drying, Microstructure, Plant cells, Scanning electron microscope, Cell deformations, Shrinkage
DOI: 10.1080/07373937.2013.837479
ISSN: 0737-3937
Subjects: Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > FOOD SCIENCES (090800) > Food Engineering (090802)
Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > MECHANICAL ENGINEERING (091300) > Numerical Modelling and Mechanical Characterisation (091307)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2014 Taylor & Francis Group, LLC
Copyright Statement: This is an Author's Accepted Manuscript of an article published in Drying Technology: An International Journal [Volume 32, Issue 4, 2014] [copyright Taylor & Francis], available online at:
Deposited On: 17 Feb 2014 22:41
Last Modified: 02 Sep 2015 01:26

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