Table 1. Changes in pH content of fish paste during 8 and 32 days of fermentation time.
Fermentation time
(days)
pH of fish paste Water content of fish paste (%)
Average + SD Average + SD
8 6.42 + 0.03a 28.81 + 1.49a
32 6.90 + 0.08b 33.85 + 1.10b
In the 8 days fermentation pH was 6.42 and in the 32 days the pH was 6.90, and it was almost reached pH 7. It
showed that there was higher base substances produced during fermentation so the pH increased. The high pH of
product probably due to the lower salt concentration used in the experiment. One of salt functions is to inhibit the
microorganism activity. By Using lower salt concentration, the activity of microorganism include the putrefaction
bacteria would be higher and the base volatile substances would be increased and would made the increased of the
pH product.
Water content was the largest compound in the fresh fish. The water content from the experimental is lower than
research of (14). Fish paste has water content approximately 35-50% (14). Water content has significantly
importance for a number reason. The determination of water content is therefore the most frequent general analysis
performed on foodstuffs. The amount of water in food often determines its nutritive value and taste. The stability
and shelf life of foods are highly dependent on water content, since it is crucial for microbiological growth and most
enzymatic activities (16). The mass loss is not only caused by loss of water but by the loss of all volatile
substances under the drying conditions, comprising those already contained in the original sample and those
produce by the heating process.
The change of moisture content in fish paste during fermentation was shown in Table 1. The longer fermentation
period gives higher water content. It was probably due to the absorption from the environment and reaction during
fermentation which liberate some volatile compound for example trimethylamin (TMA), ammonia etc. The research
of (17) reported that there was increased in water content of seasoning powder made from fish paste during storage
in aluminium foil, plastic polypropylene and oil paper packaging. The lower permeability of packaging material the
more difficult gas and moisture can be passed through the packaging. The product of this research was packed with
banana leaves that still allow the gas and moisture passed easily through the packaging so the water content would
be higher with prolonging in fermentation time.
Table 2, presents the amino content of fish paste at 2 different fermentation periods. The total free amino acid
content was 32.32 mg/100 g of sample in 8 days fermentation time (wet base) and the value increased to 37.15 at 32
days fermentation. The major amino acids present in the sample were glutamic acid, aspartid acid and arginin.