2.7. Foaming capacity and foam stability

Foaming capacity (FC) and foam stability (FS) of sample solution (1%, w/v) was determined according to the method of Park et al. (²⁰¹⁶). Briefly, 10 ml of 1% (w/v) sample solution was homogenized in a 25‐ml volumetric cylinder with a homogenizer at a speed of 12,500 rpm for 1 min at room temperature. The sample was allowed to stand for 1, 15, 30, and 60 min, respectively. FC and FS were then calculated by using the following equations:

Foaming capacity (%) = VT/V₀ × 100

Foam stability (%) = (Ft/Vt)/(VT/V₀) × 100

where VT is total volume after whipping; V₀ is the original total volume before whipping; and Ft and Vt are total foam and total volume after leaving at room temperature for different times (t = 15, 30 and 60 min).