Date of Award
Master of Science (MS)
Dr. Mutamed M. Ayyash
Dr. Dawood Al Ajmi
Probiotics have great positive impacts on human health. Therefore, finding new probiotics possess novel probiotic characteristics would be greatly appreciated by medical, scientific and food industrial societies. This study aimed to isolate lactic acid bacteria (LAB) from traditionally dried fishes, assess their safety aspects, characterize their probiotic features, and investigate their potential health-promoting benefits of fish sausage fermented by selected LABs, in-vitro
Out of one hundred and fifty (150) isolates, 85 isolates were considered as a potential probiotic. The 85 isolates achieved a reduction under gastric juicy ranged from 0.5-5.2 log10 CFU/mL during 2h of incubation and they were more vulnerable toward oxgall compared with cholic and taurocholic acid. Out of 85 isolates, 29 isolates showing the considerable tolerances to gastrointestinal conditions and bile salts. Out of 29 isolates, 13 isolates had remarkable tolerances and were selected for additional characterization as potential probiotic properties. 16s rRNA sequencing was implemented to identify (13) presumptive LAB isolates. All those isolates were identified as Enterococcus spp. Classified as following: 4 E. faecalis, 7 E. faecium and 2 E. durans. With respect to the safety assessment, all evaluated isolated shown no clear-halos which expressed as no hemolysis (gamma-hemolysis). All isolates were more susceptible to penicillin and ampicillin compared to other four tested antibiotics.
According to evaluation assays of probiotic characterization; In general, 13 Enterococcus spp. Showed high cholesterol removal ranged from 6.5% to 59.1% during 24 h of incubation. The 13 Enterococcus spp. demonstrated a good percentage of autoaggregation ranging from 8.2 - 21.3 % and 29 - 67% throughout 3h and 24h of incubation, respectively.
The following 6 strains were selected to prepare functional fermented fish sausages: E. faecium MF047470, E. faecium MF047495, E. faecium MF047509, and E. faecium KY962874, E. faecalis KY962905, and E. durans KY962882. The amylase and glucosidase inhibition in fish sausages fermented by Enterococcus spp. Extended from 29.2% to 68.7% and from 23.9% to 41.4%, respectively, during 21 days of storage. The DH%, DPPH%, ABTS%, amylase and glucosidase inhibitions had a positive correlation.
Al Kalbani, Nadya Salem Sultan Saeed, "Probiotic Characterization of Lactic Acid Bacteria (Lab) Isolated From Dried Emirati Fish and the Health Promoting Benefits of Fermented Fish Sausages by Selected Isolates" (2018). Food Science Theses. 6.