Improving the whey protein foam structures by using novel acetylated triglycerides: A response surface methodology (RSM) approach

Protein foams are common to foods, such as meringue, whipped cream and mousses. Stability is a challenging issue determined by fat and sugar content. We hypothesize that acetyl-triacylglycerols (acetyl-TAG) that possess sn-3 acetate group with high oleic content can provide stability to the foam at reduced sugar concentrations by increasing the surface viscosity and minimizing serum drainage. A fractional factorial Box-Wilson design was used to investigate the effects of whey protein concentration (WPI) (2–10 wt%), sucrose concentration (SC) (10–30 wt%) and acetyl-TAG concentration (ATC) (0–1 wt%) on overrun (FO), stability against serum drainage (FD) and surface dilatational rheology. Each response was analyzed by linear regression model fitting and a backward elimination algorithm for significance (α = 0.01). FO was significantly affected (p < 0.01) by WPI and ATC, but not sucrose concentration. The optimum overrun (nearly 700%) was obtained at 9 wt% WPI and 0.6 wt% ATC. Drainage and viscoelastic properties were significantly (p < 0.01) affected by all process variables. Dynamic complex modulus (|E|) as measured using an optical tensiometer was around 30–40 mN/m when acetyl-TAG was higher than 0.5 wt%. Our findings indicated that the acetyl-TAG can be used to enhance the stability of protein foams in reduced sugar food products, however, not at high sugar concentrations (30 wt%).