Elaboración de una bebida fermentada a base de zumo de Psidium guajava (Guayaba) y caracterización de bacterias ácido lácticas

Abstract

The objective of this research was to elaborate a fermented beverage based on guava juice (Psidium guajava) and characterization of lactic acid bacteria for which three formulas were elaborated: F1 (30% guava pulp, 70% water), F2 (40% guava pulp, 60% water) and F3 (50% guava pulp, 50% water). These were subjected to spontaneous fermentation. A taste test was carried out with a group of 50 Biochemistry students, using a hedonic scale, where it was found that the F2 formulation was the most acceptable. In addition, microbiological analysis of quality indicators such as coliforms, mesophilic aerobes, and Staphylococcus aureus was performed. It showed the absence of coliforms and Staphylococcus aureus, and in the case of mesophilic aerobes, it did not show microbial growth outside the range established by the standards used for the determination of this microorganism. This is because it was kept in a sterile and innocuous environment during its preparation. The most acceptable formulas were subjected to microbiological analysis for the isolation of lactic acid bacteria colonies with possible probiotic activity using biochemical tests for their identification such as Gram staining, catalase, and oxidase. Finally, characterization tests were carried out, such as Mobility, CO2 production from glucose, growth at different temperatures, and tolerance to different pH. It was concluded that the fermented beverage based on Psidium guajava contained lactic acid bacteria that complied with the characterization and identification tests that made them possible candidates for probiotics of vegetable origin. Therefore, it is recommended that the bacterial strains obtained from this product be evaluated with molecular techniques to give them added value in the food industry.