M. Ruskova1*, T. Petrova1, I. Bakalov1, N. Penov2, A. Simitchiev2 1Food Research and Development Institute, 154 V. Aprilov, 4000 Plovdiv, Bulgaria 2Department of Canning and Refrigeration Technology, Technological Faculty, University of Food Technologies, 26 Maritza, 4000 Plovdiv, Bul