fermentation process. In contrast, the amount of gluconic acid increased
during the fermentation process of the control batch until the end of
fermentation, whereas the amount of gluconic acid in plaa-som
inoculated with mixed starter culture was higher after 24 h and then
remained stable until the end of fermentation. Plaa-som inoculated
with the mixed starter culture contained higher amounts of lactic acid
a fte r 2 4 h th an plaa-sominoculated with single starter culture or the
control fermentation batch, and the amount of lactic acid continued to
sharply increase until the end of the fermentation. The production of
or ga ni c ac id s co n tr ib ut ed t o th e de c re a se in pH a ft er 24 h of
fermentation. In addition, butyric, succinic, acetic and propionic acid
were not detected during fermentation (data not shown).
Colorimetric data – the light ness (expressed as L* value) of t he
inoculated and c ontrol ferment ation batches – showedthesamepattern.
An increase in lightness occurred a fter 24 h o f f ermentat io n and d ecreased
until the end o f fermentation. Greenness (exp ressed a s−a* va l u e) wa s
visible i n the init ia l s tage of all treatment lots an d t ransitioned to redness
(expressed as + a * val ue) aft er 48 h until the end of fermentation for a ll
fermentation batches. In contrast, yellown ess ( expressed a s + b* value)
decreased from the initial stage until the end of f ermentation i n the control
fermentation batch, whereas batches of single and mixed starter c ultures
were stable until the end o f f ermentation ( Table S2). Furthermo re, a visual
colorimetric analysis ofplaa-som inoculated with s tarter c ulture demon-strated i ncreased whiteness compared to that i n the control after 48 h o f
fermentation, but there w as no diff erence in color among the treatments.
The texture of plaa-somwas 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 (p N 0.05) (data not
shown).
The results of the sensory evaluation ofplaa-somby the panelists
indicated a more positive response to the appearance, color, odor,
texture and overall liking of plaa-sominoculated with starter culture
rather than plaa-som m a d e b y n a tu r a l f e rm e n t a t io n ( c o n t r ol ) ;
however, the s ensory evaluation s o f a ll treatments were not
significantly different ( p N 0.05) (data not shown).