Fermentation of Chao Using Proteolitic Lactic Acid Bacteria

A traditionally fermented fish from the South Sulawesi region, also known as chao, was prepared from tembang fish, salt, and fermented rice. This study employed Lactobacillus plantarum Ags 1-3 and Pediococcus acidilactici Ags 7-3 proteolytic lactic acid bacteria (LAB) as a co-starter to determine the role and potentials of producing ACE inhibitors during the fermentation process. Also, the experiment was comprised of fermentation three stages, termed salt (20%) (A-B), LAB (C-D), and mixed by the addition of fermented cooked rice with or without starter culture (E-F). While, the control was fish fermentation without the use of starter culture. Salt content, water activity, microorganism population, acid production, pH, soluble protein, and activity of angiotensin-converting enzyme inhibitor (ACE-I), were major factors monitored. The result showed during salt fermentation, the saline content in fish increased significantly from approximately 10.75% - 16.48%, with no microbial growth detected. Subsequent salt removal and starter culture inoculation enhanced the bacteria load and LAB by two log cycles, although, without the use of starter culture, the LAB quantity observed a decline. Furthermore, proteolytic lactic acid bacteria appeared to have successfully disintegrated protein into lesser molecular weight and peptides. This situation was indicated by an improvement in soluble protein, without any reduction of pH values. Proteolytic LAB tends to produce ACE inhibitor, with an activity value extending between 84-85%, while without the use of starter culture, the estimate was barely 58%. Consequently, an increase in acid production and decrease in pH occurred during mixed fermentation, as a result of readily available carbon source from the rice. However, pH of chao, without starter culture showed a higher value. Therefore, chao fermentation using proteolytic lactic acid bacteria produced ACE-I, with the tendency to reduce the reaction time.