Unwanted foam is a serious problem in some industrial processes, as it decreases production capacity and the quality of end products. For an optimal control of its formation, antifoaming agents are usually added in small doses, typically between 0.01 and 0.5%. The use of these additives improves the efficiency of production processes, since it allows the use of containers to the maximum of their capacity, avoiding overflows and facilitating pumping.
Defoamers are complex mixtures formed by materials such as oils, silicones, waxes, silica or polymers, which have a synergistic effect between them. That is, the combination of the different components provides a much greater effect than said individual components separately. This allows optimizing formulations to adapt them to the different foaming media and maximize results. (1)(2)(3)
In the food industry it is common to use defoamers based on silicone emulsions of the polydimethylsiloxane type (food code E-900). These products have a very high and immediate antifoam effect, although they lose part of their effectiveness over time. This makes the constant addition of antifoaming agent necessary throughout the production process to maintain its effectiveness. (4) Moreover, food legislation limits the use of silicones to certain categories of food.(5)
For this reason, CONCENTROL formulated the product EMULTROL DFM OLV-55 FG from vegetable oils, which makes its spectrum of application wider than that of silicones and makes it suitable for processing dairy products, beverages, fruit, vegetables, soups and meat sub-products, among others. Additionally, the particular combination of its components improves the antifoaming effect in the long term compared to other products on the market.
In the present study, the effectiveness and durability of the defoamer EMULTROL DFM OLV-55 FG in several plant media at different temperatures has been evaluated. Specifically, the tests have been carried out using aqueous suspensions of chickpeas and spinach, at room temperature and at 80 ºC, with the objective of simulating the conditions found in the processing of legumes and vegetables. Additionally, the obtained results have been compared with those provided by a silicone-type antifoaming agent widely used in the sector.
For the antifoaming tests, the Bikerman test or bubbling method has been used, which consists of the formation of foam by introducing gas into the medium through a porous glass located at the bottom of a graduated test tube (Figure 1). This method allows a quantitative comparison of the effectiveness and durability of several defoamers due to precise control of the degree of foaming.(6)
Figure 1 – Bikerman test or bubbling method
In our study, 100 ml of foam medium was placed in a 250 ml test tube and 0.1% antifoaming agent was added. The bubbles are generated by blowing nitrogen at a constant flow rate of 0.2 l / min. The foam volume is measured as a function of time to determine the antifoaming activity.
In the case of an aqueous suspension of chickpeas, rich in proteins and starch, it is observed that EMULTROL DFM OLV-55 presents initial antifoaming effectiveness similar to traditional silicone defoamers, at both temperatures. However, the silicone antifoaming agent loses part of its effectiveness within a few minutes of being added, whereas EMULTROL DFM OLV-55 remains stable over time (Figure 2).
Figure 2- Tests carried out on an aqueous suspension of chickpeas.
In the case of an aqueous suspension of spinach, rich in cellulose, it is observed that both antifoaming agents have a similar activity profile. However, EMULTROL DFM OLV-55 is shown to be more effective than traditional silicone ones at elevated temperatures (Figure 3).
Figure 3- Tests carried out on an aqueous suspension of spinach.
Therefore, we can conclude that the product EMULTROL DFM OLV-55 shows an excellent antifoaming effectiveness, both at high and low temperatures, comparable to traditional silicone-based products. In addition, it has the advantage of maintaining its action in the long term, which allows reducing the addition of antifoaming agent during the process. All this considering that it is a product based on vegetable oil suitable for direct contact with food.
(1) Garrett, P. R., Defoaming. Theory and Industrial Applications; Surfactant Science Series, Vol. 45, 1993.
(2) Pugh, R. J. Foaming, foam films, antifoaming and defoaming. Adv. Colloid Interface Sci. 1996, 64, 67.
(3) Pelton, R.; Flaherty, T. Defoaming: linking fundamentals to formulations. Polymer Int., 2003, 52, 479.
(4) Garrett, P. R., The Science of Defoaming. Theory, Experiment and Applications; Surfactant Science Series, Vol. 155, 2013.
(5) REGLAMENTO (CE) No 1333/2008 DEL PARLAMENTO EUROPEO Y DEL CONSEJO de 16 de diciembre de 2008 sobre aditivos alimentarios.
(6) Denkov, N. D. Mechanisms of Foam Destruction by Oil-Based Antifoams. Langmuir, 2004, 20, 9463.