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Applicability of Foam Mat Drying Process for Production of Instant Cocoa Powder Enriched with Lavender Extract§ 

Ana Maria Buljat, Tamara Jurina*orcid tiny, Ana Jurinjak Tušekorcid tiny, Davor Valingerorcid tiny, Jasenka Gajdoš Kljusurićorcid tiny and Maja Benkovićorcid tiny 

University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10000 Zagreb, Croatia  

Article history:  
Received: 27 September 2018 
Accepted: 17 June 2019  

Key words
foam mat drying, cocoa, lavender, powder flow, modelling 

The foam mat drying process is a simple and economical alternative to spray and freeze drying. It is considerably cheaper due to rapid drying at low temperatures, preservation of nutritional quality and easy reconstitution. Basic principle of the process is conversion of a liquid or a semi-liquid foodstuff to foam and thin layer drying of the foam. This study explores the possibility of the foam mat drying for production of instant cocoa powder enriched with lavender (Lavandula × hybrida L.) extracts. The aqueous extraction of lavender was optimized using Taguchi orthogonal array design. Extracts obtained under optimal conditions were added to a mixture of egg white, cocoa powder, sugar and gelatine. Mixtures were blended for 4 min to obtain stable foam which was dried at three different temperatures (t=50, 60 and 70 °C) and milled into a powdered product. Drying rates were obtained from the experimental data using nonlinear model estimation. Flow properties, bulk density, particle size distribution, reconstitution and sensory properties of the final product were also assessed. Based on the obtained data, the drying process was best described by Page’s drying model. Samples dried at lower temperature (t=50 °C) exhibited the best powder flow and reconstitution properties. Sensory analysis resulted in similar findings: powder samples dried at lower temperatures had better appearance, colour and taste. The obtained data confirm the suitability of the foam mat drying for the production of instant cocoa powder enriched with lavender extract.    

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§Paper was presented at the 9th International Congress of Food Technologists, Biotechnologists and Nutritionists, 3–5 October 2018, Zagreb, Croatia