Einkorn (Triticum monococcum L.) and nectarine flour mixture - antioxidant activity, microbiological and sorption characteristics

¹ Department of Mechanical and Instrument Engineering, Faculty of Mechanical Engineering, Technical University of Sofia, Branch Plovdiv, 25 Tsanko Diustabanov Str., Plovdiv 4000, Bulgaria
² Department of Process Engineering, Technical Faculty, University of Food Technologies - Plovdiv, 26 Maritsa Blvd, 4002 Plovdiv, Bulgaria
³ Department of Analytical Chemistry and Physical Chemistry, Technological Faculty, University of Food Technologies - Plovdiv, 26 Maritsa Blvd, 4002 Plovdiv, Bulgaria
⁴ Department of Milk and Dairy Products Technology, Technological Faculty, University of Food Technologies, 26 Maritsa Blvd, Plovdiv, 4002, Bulgaria
⁵ Institute of Food Preservation and Quality - Plovdiv, 154 Vasil Aprilov Blvd., 4003 Plovdiv, Bulgaria

^* Corresponding author: adelina.bogoeva@abv.bg

Abstract

The current paper presents the initial scientific research on a new enriched flour mixture with nectarine powder, comprising physicochemical parameters, antioxidant capacity, microbiological load, and sorption characteristics data. A mixture of 70% Einkorn flour and 30% fruit powder of Bulgarian origin as a functional food supplement was blended. The presence of bioactive components was proved by the in vitro analysis of antioxidant activity through DPPH, ABTS, FRAP, and CUPRAC methods. The microbiological indicators, the total count of mesophilic aerobic and facultative anaerobic microorganisms, yeasts and molds, Escherichia coli, Salmonella spp., coagulase-positive staphylococci and coliforms, were within the permissible norms and no presence of pathogenic microorganisms, were detected in the flour mixture. Adsorption and desorption processes were studied at 10, 25 and 40°C and a_w = 0.112-0.868 following static gravimetric methods. The obtained S-shaped equilibrium sorption isotherms confirm the constant trend that with increasing equilibrium moisture content, the temperature decreases in conditions of constant water activity. Based on the obtained sorption capacity data, a calculation of the monolayer moisture content was made using the linearization of the BET model. One of the modified three-parametric models of Oswin, Halsey, Henderson, and Chung-Pfost was selected as a suitable model for describing all sorption isotherms.