Effect of Gluconacetobacter spp. on kefir grains and kefir quality

Abstract

Microbial, chemical, physical, and sensorial analyses of kefir samples produced using kefir grains embedded with Gluconacetobacter spp. were investigated using kefir samples with Gluconacetobacter spp. inclusion (KA), and regular kefir grains (control, KC) lacking Gluconacetobacter spp. The genus Gluconacetobacter, (identified using PCR) isolated from apple cider vinegar, was embedded in kefir grains. Inclusion of Gluconacetobacter spp. provided a significant biomass increase (p < 0.01). The Lactobacillus spp., Lactococcus spp., yeast, Lactobacillus acidophilus, and Bifidobacterium spp. contents of KA were similar to KC. The acetic acid bacterial content of KA was 3.86 log CFU/mL. A significant (p < 0.05) increase was observed in the exopolysaccharide content and viscosity of KA compared with KC. Inclusion of a different useful bacterium not naturally present in kefir grains is herein reported. Kefir grains can be an important carrier for microorganisms.