Colorimetric data – the lightness (expressed as L* value) of the
inoculated and control fermentation batches – showed the same pattern.
An increase in lightness occurred after 24 h of fermentation and decreased
until the end of fermentation. Greenness (expressed as −a* value) was
visible in the initial stage of all treatment lots and transitioned to redness
(expressed as +a* value) after 48 h until the end of fermentation for all
fermentation batches. In contrast, yellowness (expressed as +b* value)
decreased from the initial stage until the end of fermentation in the control
fermentation batch, whereas batches of single and mixed starter cultures
were stable until the end of fermentation (Table S2). Furthermore, a visual
colorimetric analysis of plaa-som inoculated with starter culture demonstrated
increased whiteness compared to that in the control after 48 h of
fermentation, but there was no difference in color among the treatments.
The texture of plaa-som was determined by comparing the results
in compression (hardness) of fresh fish (0 h) with the finished
products of all fermentation batches. This indicated that the hardness
of all treatments was not significantly different (pN0.05) (data not
shown).
The results of the sensory evaluation of plaa-som by the panelists
indicated a more positive response to the appearance, color, odor,
texture and overall liking of plaa-som inoculated with starter culture
rather than plaa-som made by natural fermentation (control);
however, the sensory evaluations of all treatments were not
significantly different (pN0.05) (data not shown).