3.8. Colour of gelatin gel
The colour of the gelatin gel from seabass skin with different
extraction temperatures and times expressed as L⁄, a⁄ and b⁄ is
shown in Table 1. A lighter colour (L⁄-values) was observed for gelatin
gels extracted at 45 _C, compared with those of gelatin
extracted at 55 _C (P < 0.05). At an extraction temperature of
45 _C, the L⁄-values of gelatin gels slightly decreased withincreasing extraction times (P < 0.05). It was found that a decrease
in redness (a⁄-value) was observed when the extraction temperatures
and times increased (P < 0.05). Nevertheless, no differences
in the a⁄-values were found between gelatins extracted at different
temperatures (P > 0.05). For yellowness (b⁄-value), an increase was
observed in all the gelatin gels when the extraction temperatures
increased (P < 0.05). This might be due to a non-enzymatic browning
reaction taken place at the higher temperature, especially
when the extraction time increased (Ajandouz&Puigserver,
1999). Amongst all the gelatin samples, those extracted at a lower
temperature (45 _C) for the shortest time (3 h) showed the lowest
total difference in the colour value (DE⁄) (71.57) with the highest
lightness (L⁄-values). Benjakul et al. (2009) reported that pigments
could be removed during pretreatment prior to gelatin extraction.
These results showed that the extraction conditions had the impact
oncolour of gelatin extracted from the skin of seabass.