Real time control of the final quality of freeze-dried lactic acid starters

Real time control of the final quality of freeze-dried lactic acid startersStéphanie Passot, Ioan Cristian TréléaUMR 782 Génie et Microbiologie des Procédés Alimentaires (GMPA), AgroParisTech, INRA, Université Paris-Saclay, F-78850, Thiverval-GrignonFreeze-drying is a time- and energy-consuming process whose management at the industrial level is still not well controlled or optimised, leading to losses in starter quality.The aim of our work was to develop a mathematical model and a computer network architecture that would make it possible to control and optimise the process and the final quality of the starter in real time. During the first stage of the experiment, quantitative relationships between the functionalities of starters and the process variables were defined.We showed that the degradation rate of the biological activity of starters during freeze-dried storage could be linked to their thermal history during the process -especially to the temperature difference between the product and its glass transition temperature- and to their final water activity. We designed the management tool by combining process data with an optimisation algorithm in order to adjust process variables in real time and to remain as close as possible to the optimal quality defined beforehand. This tool was validated at the pilot scale level and can be easily transferred to other types of equipment.PartnershipUniversity of Rome Tor VergataSpanish Council for Scientifi c ResearchSoredabSocietà di Progettazione Elettronica e Software, Alctra, TelstarEuropean Project CAFE (Computer-Aided Food processes for control Engineering)Read moreL.T. Antelo, S. Passot, F. Fonseca, I.C. Tréléa, A.A. Alonso (2012). Toward Optimal Operation Conditions of Freeze-Drying Processes via a Multilevel Approach. Drying Technology 30:1432-1448.Stephanie.Passot@grignon.inra.fr, Cristian.Trelea@grignon.inra.fr Génie et Microbiologie des Procédés Alimentaires, INRA-AgroParisTechhttp://www6.versailles-grignon.inra.fr/gmp