Prototype of an Innovative Vacuum Dryer with an Ejector System: Comparative Drying Analysis with a Vacuum Dryer with a Vacuum Pump on Selected Fruits

Zdravko Šumić; Aleksandra Tepić Horecki; Vladimir Kašiković; Andreja Rajković; Lato Pezo; Tatjana Daničić; Branimir Pavlić; Anita Milić

doi:10.3390/foods12173198

Prototype of an Innovative Vacuum Dryer with an Ejector System: Comparative Drying Analysis with a Vacuum Dryer with a Vacuum Pump on Selected Fruits

Foods. 2023 Aug 25;12(17):3198. doi: 10.3390/foods12173198.

Authors

Zdravko Šumić¹, Aleksandra Tepić Horecki¹, Vladimir Kašiković², Andreja Rajković³, Lato Pezo⁴, Tatjana Daničić¹, Branimir Pavlić¹, Anita Milić¹

Affiliations

¹ Faculty of Technology Novi Sad, University of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia.
² Independent Researcher, 21000 Novi Sad, Serbia.
³ Research Unit Food Microbiology and Food Preservation, Department of Food Technology, Safety and Health, Faculty Bio-Science Engineering, Ghent University, 9000 Ghent, Belgium.
⁴ Institute of General and Physical Chemistry, University of Belgrade, 11000 Belgrade, Serbia.

Abstract

The following article describes new research about the design, construction and installation of the new prototype of a vacuum dryer with an ejector system. Moreover, the testing of this new prototype involved comparing the qualities of fruit dried in a vacuum drier with an ejector system to fruit dried in a convectional vacuum drier. The data obtained were then analyzed and presented. Due to their economic relevance and highly valuable nutritional value and sensory properties, sour cherries and apricots have been chosen to be the subjects for the testing. The most appropriate quality indicators for analyzing were moisture content, a_w value, share and penetration force, total phenol, flavonoid and anthocyanin content and antioxidant activity (FRAP, DPPH and ABTS test). The main results of this study were achieved by designing, constructing, installing and testing the usage of the innovative prototype of a vacuum dryer with an ejector system in the laboratory of the Technology of fruit and vegetable products of the Faculty of Technology Novi Sad, University of Novi Sad. Based on our analyses of the obtained data, it was concluded that vacuum dryer with an ejector system are similar to vacuum dryer with a vacuum pump in terms of all tested physical, chemical and biological properties of dried samples. We observed similarities in some of the most important parameters, including product safety and quality, such as the a_w value and the total phenol content, respectively. For example, in dried sour cherry, the a_w values ranged from 0.250 to 0.521 with the vacuum pump and from 0.232 to 0.417 with the ejector system; the total phenol content ranged from 2322 to 2765 mg GAE/100 g DW with the vacuum pump and from 2327 to 2617 mg GAE/100 g DW with the ejector system. In dried apricot, the a_w ranged from 0.176 to 0.405 with the vacuum pump and from 0.166 to 0.313 with the ejector system; total phenol content ranged from 392 to 439 mg GAE/100 g DW with the vacuum pump and from 378 to 428 mg GAE/100 g DW with the ejector system.

Keywords: ejector system; energy efficiency; physico-chemical properties; prototype; vacuum dryer.

Grants and funding

Development of a prototype vacuum dryer with ejector system (No. 1068) within the Technology Transfer Program; Project 451-03-47/2023-01/ 200134/Fund for Innovation Activity of the Republic of Serbia; Ministry of Education, Science and Technological Development