Fatemeh Zarei
Halal Research Center Islamic Republic of Tehran, Iran.
Title: Optimization and identification of cultivation conditions and the possibility of producing probiotic microorganisms producing GABA (gamma-aminobutyric acid) from indigenous dairy of west of Iran and using in whey protein drink
Biography
Biography: Fatemeh Zarei
Abstract
Isolation and identification of probiotic bacteria from native strain have a very important role in the food industry as well as increasing the health of the community. Lactic acid bacteria play a pivotal role in fermentation processes. One of the metabolites produced by this starin of bacteria is gamma aminobutyric acid (GABA). It has a variety of physiological functions such as the induction of hypertensive, diuretic, anti-depression, and tranquilizing effects. The general objective of this research was to optimize and identify the conditions of cultivation and the possibility of producing probiotic microorganisms producing GABA from indigenous Iran to be utilized in whey protein drink. In the first part of this study, 50 bacterial samples from indigenous dairy products (yogurt, dough, cheese and butter) were isolated in western Iran. Initial diagnostic tests including stain gram, oxidase and catalase tests were performed to detect lactic acid bacteria. Results showed that only 10 strains were gram positive, negative catalase and negative oxidase, and were known as Lactic Acid Bacteria (LAB). Then, probiotic properties including acid resistance, bile, gastric juice, and hemolysis inactivity and L-arginine hydrolysis were evaluated. Three LAB samples with strong probiotic properties were selected from them, followed by identification of the primers with 16SrDNA by sequencing and drawing phylogeny tree, the results showed that Lactobacillus paracaosi, Lactobacillus plantarum and Pediococos acidilactici strains isolated from yogurt and dough and cheese, respectively, had the highest probiotic properties. In the second part, the concentration of GABA production by probiotic bacteria was evaluated by HPLC in two media of MRS Broth and whey protein. Based on HPLC results, Lactobacillus plantarum, grown in MRS broth had shown the highest concentration of GABA production with 115.4 ppm. In order to increase the amount of GABA produced, the conditions of the culture medium (temperature range (30 to 50 °C), pH (4 to 6), time (12 to 72 h) and glutamic acid concentration (25 to 250 mM) were optimized. The optimized conditions resulted in an increase in the production of GABA to reach170.942 ppm. In the third part of this study, the bacterium was added under optimal conditions of culture medium at 37.77 °C, pH 5.19, 250 mM glutamic acid and 72 hours in whey protein drink containing concentrate of banana and strawberry, and the viability properties, production GABA and its sensory evaluation within 30 days. The results of this study showed that the highest viability rate on the on day 30 of whey drink with strawberry at 25°C was (8.1Log10cfu / ml) and the highest amount of GABA on day 30th of production of whey drink containing banana stored at 25°C (195.5ppm). A sample of whey drink containing banana stored at 25°C was recognized as a superior treatment due to higher levels of GABA. In conclusion, Using indigenous and resistant species of probiotic bacteria and optimizing bacterial growth conditions, more GABA can be produced in food products and a positive step towards the development of pragmatic products and the promotion of consumer health.