Desorption capacity of raw energy bars with fruits of Zizyphus jujuba Mill. - Bulgaria

^1* Department of Process Engineering, University of Food Technologies – Plovdiv, 26 Maritza Blvd. BG-4002 Plovdiv, Bulgaria
² Department of Mechanical and Instrument Engineering, Technical University - Sofia, Plovdiv Branch, 25 Tsanko Duistabanov Str., Plovdiv 4000, Bulgaria
³ Department of Technology of Grain, Fodder, Bread and Confectionery Products, University of Food Technologies – Plovdiv, 26 Maritza Blvd. BG-4002 Plovdiv, Bulgaria
⁴ Language Training Centre, University of Food Technologies – Plovdiv, 26 Maritza Blvd. BG-4002 Plovdiv, Bulgaria
⁵ Centre of Physical Education and Sport, University of Food Technologies – Plovdiv, 26 Maritza Blvd. BG-4002 Plovdiv, Bulgaria

^* Corresponding author: aldurakova@abv.bg

Abstract

The current study presents a mixture for raw energy bars of fresh fruits of the exotic fruit Zizyphus jujuba Mill. with origin - Bulgaria. The physico-chemical indices of the ready mixture are analyzed. A high content of carbohydrates - 24.45% and of nourishing fiber - 22.08% is reported. The desorption capacity of the exotic mixture is examined for temperatures of 10°С, 25° and 40°С in eight watery activities from 11% to 85%. The analysis shows that the equilibrium moisture lowers with the raise of temperature in constant watery activities. The desorption isotherms are of type III according to the classification of Brunauer et al. The modified model of Halsey is recommended for the isotherms description according to the estimation criteria distribution, and the model of Oswin - as a second modified model. The values of the monolayer moisture content in a_w <0.5 for temperatures 10°С - 5.46% dry basis (d.b.), 25°С - 5.72% d.b. and 40°C - 4.05% d.b. are calculated Brunauer-Emett-Teller model.