The microstructures of gelatin gels from
cuttlefish skin incorporated without and with
phenolic compounds or extracts oxidised by laccase
are illustrated in Figure 3. Similarly, all gelatin
gels contained the pores with different sizes and
uniformity. The control gel showed a uniform
network with a thin strands (Figure 3 A). Gelatin gel
incorporated with oxidised phenolic compounds or
extracts varied in structure. Amongst all gels, that
added with oxidised ECBE had the largest void with
varying sizes (Figure 3B). This might be associated
with the poorer gel. For gel added with oxidised gallic
acid which showed the highest gel strength, the small
voids were obtained but the strand was thick (Figure
3F). The structure would be resistant to the force
applied as evidenced by the highest gel strength of
this gel. Therefore, the oxidised phenolic compounds
or extracts could function as the gelatin cross-linker,
in which the oxidised forms were able to induce the
cross-linking more effectively. As a consequence, the
gel strength could be improved with the addition of
either extracts or commercial phenolic compounds
oxidised by laccase.