Food aeration: Effect of the surface-active agent type on bubble deformation and break-up in a viscous Newtonian fluid: From single bubble to process-scale. (March 2023)

• Record Type: Journal Article
• Authors: Sanogo, B.; Souidi, K.; Marcati, A.; Vial, C.
• Is Part Of: Food research international. Volume 165(2023)
• Publication Date: 2023-03
• Subjects: Continuous aeration process -- Bubble break-up -- Tip-streaming -- Simple shear flow -- Protein -- Surfactant; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2023.112478
• Languages: English
• ISSNs: 0963-9969

Abstract

Graphical abstract: Highlights: Food aeration at pilot scale was investigated using two technologies and three surfactants. Whey proteins (WPC) are a better foaming agent than sodium caseinate (SCN) and tween 20 (TW20). Experimental data were confronted to the visualization of single bubble break-up under shear flow. WPC and SCN promoted bubble break-up by tip streaming ; TW20 only deformed bubbles. Single bubble break-up needs higher shear with WPC than SCN, but kinetic limitations appear with SCN during aeration. Abstract: Two continuous whipping devices, a rotor–stator (RS) and a narrow angular gap unit (NAGU), were used to produce aerated food with a 25% (v/v) gas fraction target. The liquid phase was a Newtonian model-solution containing 2% (w/w) of either whey proteins (WPC), sodium caseinate (SCN), or tween 20 (TW20). Strong differences emerged regarding gas incorporation and bubble size as a function of process parameters: namely, rotation speed and residence time. To improve understanding of the results obtained at pilot-scale, a second investigation consisting in the observation of the deformation and break-up of single gas bubbles has been undertaken using successively a Couette device and an impeller close to NAGU. For proteins, the observation of single bubble deformation and break-up showed that bubble break-up occurred by tip-streaming above a well-defined critical Capillary number Cac of 0.27 and 0.5 for SCN and WPC, respectively, whereas no break-up was observed with TW20 even though Ca reached 10. The poor foaming ability obtained with TW20 could be explained by a poor break-up mechanism, promoting coalescence and gas plugs at high shear instead of gas incorporation. Conversely, protein promote tip-streaming as the major break-up mechanism at low shear rate, explaining why rotation speed is not a key process parameter. Differences observed between SCN and WPC can be attributed to diffusion limitation for SCN when a much larger surface area is generated during aeration.