El Pulque: Características Microbiológicas y Contenido Alcohólico Mediante Espectroscopia Raman

Three strains were isolated from a pulque in Tlaxcala Mexico. Different morphological groups were identified: Gram-negative coccobacilli, regular nonsporing Gram-positive rods and yeast. Each strain was identified with Zymomonas sp, Lactobacillus sp and Saccharomyces sp. The developed consortium was the responsible for the alcoholic, acid, and viscous fermentation which are special characteristics of this traditional Mexican beverage. The alcohol content varies in function of the fermentation time reaching percentages of 10.35 % (v/v) and 9.01 % (v/v) in the so called «run» stage. They are determined by gas chromatography and Raman spectroscopy. The end product has a high content of proteins (1 g/l), sugar reducers (4.75 g/l) and microbial populations in ranks of 45x108 UFC/mL for Saccharomyces sp., 41x107 UFC/mL for Zymomonas sp and 34x106 UFC/mL for Lactobacillus sp, that give the drink a high nutritional value. The microorganisms could be beneficial to the digestive system when ingested orally.