Affiliation:
1. Department of Food and Nutrition University of Helsinki P.O. Box 66 Helsinki 00014 Finland
2. School of Agriculture and Food Sustainability The University of Queensland Brisbane 4072 QLD Australia
3. ARC Dairy Innovation Hub, School of Agriculture and Food Sustainability The University of Queensland Brisbane 4072 QLD Australia
Abstract
Left‐over frothed milk in most coffeehouses is typically discarded, leading to wastage of a lot of milk due to a common belief that frothed milk is unable to re‐foam. We investigated the foaming and physical properties of frothed reconstituted skim milk (1.5–15%, w/w) foamed up to four times. The results showed that at all investigated solid concentrations and foaming times, milk samples retained their high foamability and foam stability, and uniform micro‐foam structure. Similarly, properties of milk samples including viscosity (1.9–3.3 Pa.s), absolute zeta‐potential (25.5–27.2 mV) and surface tension (54.8–59.7 mN/m) remained unchanged even after re‐foaming multiple times.