Biology Reference
In-Depth Information
Salt
Salt is used to draw liquid out of the fi sh and to control the fermentation.
Thus, the high salt content (20-30%) ensures that spoilage due to bacteria
is prevented and that the number of bacteria present drops as quickly as
possible during fermentation. From a nutritional point of view, however,
it would be best to use as little salt as possible. The high salt concentration
also slows down the fermentation speed. (Berkel et al., 2004; Rao and
Stevens, 2006).
Traditional (Natural) Fermentation
The fermentation methods described in this chapter are mostly traditional
methods. This means that the fermentation is allowed to take place
naturally (spontaneous fermentation) and is guided by experience. No
control is exerted over the fermentation. If enough salt is added, about 30%
of weight of the fi sh, and there is no infl ux of air during the fermentation
process (anaerobic environment), the fermentation will proceed by itself.
The fermentation methods are more or less standard for a given region.
Local adaptations or changes in the procedure can, of course, be found.
Experience will help determine whether or not the fermentation has
gone well. If the product is different than is normal, for example if it has
a different colour or smell, the product should not be eaten. Traditional
fermented fi sh products are divided into two groups:
• Products which, in the presence of salt, are fermented by the enzymes
present in the fi sh fl esh and intestines;
• Products which are fermented in the presence of boiled or roasted
rice. Usually in South-East Asia boiled rice is added to the fi sh-salt
mixture.
Fermentation Using Starter Culture
The use of starter culture in food fermentation has become a means to
increase processing rates and product consistency. Starters are used to
improve the sensory characteristics and microbiological quality and to
shorten the fermentation time of fermented foods (Visessanguan et al.,
2006). Of late, the LAB starter such as
Lactobacillus plantarum
,
L. brevis,
L. fermentum, Pediococcus acidilactici, P. pentosaceus,
etc are being used
commercially for the production of traditional fi sh products like
som fug
(Riebroy et al., 2008) and other fi sh-based food products (Gelman et al.,
2001).
