Publications in year 2014

Vol. 21, Issue 4



Shrinkage and mechanical properties of defrosted strawberries dried by convective, vacuum and convective-vacuum methods

International Agrophysics
Year : 2014
Volumen : 21
Issue : 2
Pages : 193 - 204
  PDF 537.65 KB
Authors: Dariusz Piotrowski1, Aleksandra Gołoś1, Piotr Grzegory1

1Department of Food Engineering and Process Management, Faculty of Food Science, SGGW – Warsaw University of Life Sciences ul. Nowoursynowska 159C, 02-776 Warszawa
Abstract :

The mechanical properties are among the most important indicators of the quality of food. They are the most important criteria for acceptance of the raw material by the consumer. Texture of fruits and vegetables is affected by the drying process – closely related to the composition and structure of cell walls – and its parameters. Research material for the study was strawberries of the variety SengaSengana. Axial shrinkage in the vertical plane was determined by linear measurements for 4 strawberries before drying and for the same strawberries after drying, using an electronic caliper. The mechanical properties of dried strawberries were analysed by compression tests (compression curves and maximum compression force). The test was carried out on texture analyser TA-TX2 2i (Stable Micro Systems). In this paper three methods of strawberry drying: convection, vacuum, convection-vacuum in various temperatures are presented. It was found that the largest shrinkage appears in convection drying and the lowest in vacuum drying. Increase of vacuum and convection drying temperature caused lower shrinkage. The curves of maximum compression and the compressive force showed that convection dried strawberries and convection-vacuum dried strawberries are more crisp and hard than strawberries dried by the convection method which are characterised by the lowest values ​​of compression force.

Keywords : drying temperature, drying methods, strawberries, shrinkage, compression curves, maximum compression force
Language : English