Isolation and optimization of growth condition of halophilic organisms for fermented food industry
1991
Wanna Pornsettakul
Two hundred and eighty three halophilic bacteria isolations obtained from sixteen samples of fish sauce from Samut Prakan province of different ages, were screened for protease activity. Bacillus sp. could give the highest protease activity. Fish sauce was fermented by using 600 g Pla Katak (Stolephorus spp.) with the incorporation of 1.5 g. crude protease having 546,075 units, which was added with 150 g. of fine powdered salt. This was compared with the control which did not include crude protease. This was incubated at 37 deg C and maintained for 20 weeks. Fish sauce fermentation with 1.5 g crude protease gave higher amount of formal nitrogen, amount of free amino acid content and the decreasing rate of pH than fish sauce fermentation wihtout crude protease. Comparison of fish sauce fermentation for 20 weeks with and without crude protease found that the degree of protein hydrolysis was 12.8 and 10.0 mg formal N/ml, the amount of free amino acid was 11.0 and 7.0 mg/ml, the pH was 5.47 and 5.97 and absorbance at 400 nanometre was 3.10 and 3.40 respectively. The role of crude protease from Bacillus sp. in the process of fish sauce production appeared to directly involve protease activity by helping in the fish protein-hydrolysing process, liberating various important amino acids for fish sauce production.
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