it
seems probable that they contribute to foaming properties. Clark,
Wilde, and Marion (1994) showed that a similar level of added
PINs (0.5%) in beer increases foam stability. Although DL and beer
have different protein levels [ca. 20 mg/mL vs. 4 mg/mL (Clark
et al., 1994), respectively], this indicates that even a small fraction
of PINs improves foaming properties. According to Dubreil,
Vie, Beaufils, Marion, and Renault (2003), PINs’ strong stabilization
properties result from formation of stable viscoelastic films of
aggregated proteins at the interface. Furthermore, the PIN fraction
of total proteins in DL from fermented dough was higher than that
of other samples. Future work in this area can include determination
of interfacial shear and dilatational elasticity of the
abovementioned dough liquor samples. That way, the impact of
interfacial film viscoelasticity on foam stability can be analyzed