The effects of the degree of gelatinization on the expansion and
the number of bubbles is summarized in Fig. 4, displaying the density
(inverse with the expansion) and the number density of bubbles
as a function of DG. Symbols represent data from (Sjöqvist
and Gatenholm, 2005; Case et al., 1992), and the right panel is
based on observations from (Tongdang et al., 2008). Lowering the
DG will lower the viscoelastic properties, and enhance the expansion.
This is however at the expense of the lowering of the number
of nucleation sites. At DG = 0.6 the expansion saturates due to collapse
phenomena – as the viscoelastic properties are too weak