Start time: 
Wednesday, 5 November 2014, 14:00 CET
Presenter name: 
Giorgia Spigno
Presenter institution: 
Università Cattolica del Sacro Cuore of Piacenza

CGA, also called microfoams, are surfactant stabilised microbubbles. They differ from regular foams since the bubbles are encapsulated in a multi-layered shell consisting of surfactant and liquid instead of a monolayer of surfactant molecules. The most important characteristics of CGA are:(i) their high stability compared to conventional foams, (ii) their high interfacial area due to their small size;(iii) sufficient stability to allow them to be pumped from the generation point to the point of use without loss of their original structure,(iv) they can be easily separated from the bulk liquid without mechanical aid, as opposed to conventional liquid–liquid extraction methods and the aqueous two phase separations that need centrifugation for phase separation.Due to these properties, CGA are highly suitable for separation and mass transfer applications. For example, CGA have found numerous applications for the recovery of a wide variety of valuable materials  including bioproducts (i.e. proteins, bacterial cells, enzymes, carotenoids, dyes)  and antioxidants.The main focus of this webinar is on the application of CGA to the recovery of bioproducts from agri-food wastes. First, characteristics of CGA and main operating parameters influencing their generation and properties will be presented.  Then, the basic principles of a CGA-based separation process together with the main parameters useful for evaluation of the process efficiency, will be explained, together with the main operating parameters influencing separation of bioproducts. Finally, the application of CGA to the recovery of polyphenols from wine-making wastes will be reported as a case study, including comments on feasibility to industrial application and economical evaluation.Research on this subject has been recently funded by the Ager project Valorvitis (grant n. 2010-2222) and 2013 Seligman Fellowship by SCI.References on CGA  Spigno, G., et al. (2014).  Colloidal gas aphrons based separation process for the purification and fractionation of natural phenolic extracts. Food Bioproducts and Processing, F., et al. (2013). Fractionation of a Red Grape Marc Extract by Colloidal Gas Aphrons. CEt Chemical Engineering Transactions, 32, 1903-1908.Spigno, G., et al. (2010). Recovery of gallic acid with colloidal gas aphrons generated from a cationic surfactant. Separation and Purification Technology 71, 56–62.Dermiki M., et al. (2009). A Mechanistic Study of Recovery of Astaxanthin from Standard Solutions using Colloidal Gas Aphrons. Separation and Purification Technology 65, 54-64.Fuda, E., & Jauregi, P. (2006). An insight into the mechanism of protein separation by colloidal gas aphrons (CGA) generated from ionic surfactants. Journal of Chromatography B 843, 317-326.Audience can find further feedback in the following article:Galanakis, C. M. (2012). Recovery of high added-value components from food wastes: conventional, emerging technologies and commercialized applications. Trends in Food Science & Technology, 26(2), 68-87. full presentation and the recording of the session can only be accessed by IFA-members. Non IFA-members can ask for access against a small handling fee of 30 € at office [AT] iseki-food [dot] net


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