Drainage of real and vegan milk foams

Milk foams are fragile objects, often stabilized in frothy cappuccinos by proteins such as caseins

and whey. The life and death of these desirable foams are scripted primarily 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 popularly sold plant-based milks: almond, oat, soy, pea, coconut, and rice. Foam creation

methods involving mechanical agitation (via electric frother) and sparging (via dynamic foam

analyzer) 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.