Drainage of Vegan Foams

Milk foams are fragile objects, often stabilized in frothy cappuccinos by proteins such as caseins and whey or by derivatives such as sodium casienate. The life and death of these desirable foams are scripted to a large extent by the forces that drive the drainage and rupture of the thin foam films that separate individual gas pockets. In this study, the bulk foam drainage kinetics of two animal-based milks (cow and goat) was compared to that of the most commonly sold plant-based milks: almond, oat, soy, pea, coconut, and rice. Foam creation methods involving mechanical agitation (via electric frother) and sparging (via foam rise method/bubbling test) at different temperatures were employed and compared to obtain quantitative measures of foamability and foam stability of the various milks. An understanding of the temperature-dependent differences in bulk drainage behavior for animal and plant-based milks sheds light onto the macromolecular interactions and networks of proteins/lipids at liquid-air interfaces, and can ultimately lead to the improvement of vegan milks.