Microbial communities and chemical changes during fermentation of sugary Brazilian kefir

Abstract

The microorganisms associated with sugary Brazilian kefir beverage were investigated using a combination of culture-dependent and -independent methods. A total of 289 bacteria and 129 yeasts were identified via phenotypic and genotypic methods. Lb. paracasei (23.8%) was the major bacterial isolate identified, followed by Acetobacter lovaniensis (16.31%), Lactobacillus parabuchneri (11.71%), Lactobacillus kefir (10.03%) and Lactococcus lactis (10.03%). Saccharomyces cerevisiae (54.26%) and Kluyveromyces lactis (20.15%) were the most common yeast species isolated. Scanning electron microscopy showed that the microbiota was dominated by lemon-shaped yeast cells growing in close association with Lactobacillus (long and curved). Some lactic acid bacteria detected by sequence analysis of DGGE (denaturing gradient gel electrophoresis) bands were not recovered at any time through fermentation by plating. Conversely, DGGE fingerprints did not reveal bands corresponding to some of the species isolated by culturing methods. The bacteria Acetobacter lovaniensis and the yeast Kazachstania aerobia are described for the first time in sugary kefir. During the 24 h of fermentation, the concentration of lactic acid ranged from 0.2 to 1.80 mg/ml, and that of acetic acid increased from 0.08 to 1.12 mg/ml. The production of ethanol was limited, reaching a final mean value of 1.24 mg/ml.

Development of new non-dairy beverages from Mediterranean fruit juices fermented with water kefir microorganisms

“…In our experiment, LAB and TMC reached similar amount of those detected in other sugary kefirs (Sabokbar and Khodaiyan, 2014;Liu and Lin, 2000), with no significant differences between cocci and bacilli (Magalhães et al, 2010). The same findings were achieved by Irigoyen et al (2005) on milk-based kefir after two days, since lactobacilli and lactococci counts were 10 8 cfu/mL.…”

“…All these microorganisms are embedded in a resilient water-soluble branched glucogalactan matrix named kefiran (Rodrigues et al, 2005;Gulitz et al, 2011;Magalhães et al, 2010). Several of the different bacteria and yeasts that can be found in kefir are recognized as probiotics (Latorre-García et al, 2007;de LeBlanc et al, 2006;Zhou et al, 2009aZhou et al, , 2009b.…”

“…When grains are applied to ferment fruit juice, molasses or sugary solution, it is referred to as sugary kefir, water kefir or tibico (tibico's tepache) (Koutinas et al, 2009;Magalhães et al, 2010). Indeed, fruit juices contain water, sugar, proteins, amino acids, vitamins and minerals being a suitable and rich medium for microbial growth (Dias et al, 2003;Schwan, 1998) that can be used to prepare fermented beverages, like kefir, wine and other products (Duarte et al, 2010).…”

Characterization of pomegranate juice and whey based novel beverage fermented by kefir grains

“…They attributed this drop to a decrease in lactose amount and a consequent increase in lactic acid content. On the other hand Magalhães et al (2010) reported production of lactic acid during fermentation of kefir is of great importance due to its inhibitory effect on both spoilage and pathogenic microorganisms. So it can be said reduction in pH value moreover leads to increase in total acidity, causes an inhibition of spoilage and pathogenic microorganism growths, too.…”

Evaluation of antagonistic activity of milk fermented with kefir grains of different origins

“…The functional properties attributed to kefir include retardation of cancerous tumors, (Murofushi et al 1983;Hosono et al 1990;Hong et al 2009), activation of the immunological system (Osada et al 1994;Vinderola et al 2005), possibility of consumption in cases of lactointolerance, combating of intestinal infections, and antagonistic activity toward pathogenic microorganisms (Hong et al 2009), among others (Zubillaga 2001). Due to its microbiotic constituent, several different substances, which inhibit the growth of pathogenic microorganisms are produced, which are frequently associated with the illnesses of dietary origin (Magalhães et al 2010;Tas et al 2012). These inhibitory substances include hydrogen peroxide and bacteriocins (Helander et al 1997).…”