Characterization of kombucha microflora in fermented milk beverages

Abstract

Application of tea fungus has been increasing world-wide as it is useful for obtaining fermented tea beverages with potential therapeutic characteristics. It is known that tea fungus is composed of acetic acid bacteria and yeasts, but involved species in these consortia are various, depending on its origin and the geographical region from which it comes from. By identifying present microflore of some tea fungus, it is possible to show its typicality and differentiate it from others. Considering that obtaining tea beverages by application of tea fungus has been known for a long time, possibility of fermented milk beverages appeared as an innovative question. Hence, in this paper isolation and identification of tea fungus microflore, where presence of acetic acid bacteria Acetobacter aceti, Acetobacter pasteurianus, Gluconobacter xylinum and yeasts belonged to the genera Saccharomyces, Candida and Kloeckera was noted, has been carried out. For the making of fermented milk beverages, subsequent inoculums were applied: fermented tea, retentate obtained by ultrafiltration and concentrate obtained by evaporation in milk with different fat content (0.9%, 1% and 2.2%) and different concentration (10%, 15% fermented tea and retentates and 1.5%, 3% concentrates). Growth ability of acetic acid bacteria and yeasts in 10 different fermented milk beverages was examined, and best activity was detected in the sample with 2.2% milk fat. During 15 days storage of the fermented milk beverages at 4°C, viability of acetic acid bacteria and yeasts was very good. From microbiological aspect, application of tea fungus in fermented milk beverages production could be the base for obtaining new fermented milk beverages, but additional research of the chemical, technological, nutritive and sensorial aspects are necessary. .

Primena čajna gljive je sve više rasprostranjena u svetu i koristi se za dobijanje fermentisanog čajnog napitka, sa potencijalnim terapeutskim svojstvima. Poznato je da čajnu gljivu čini simbioza sirćetnih bakterija i kvasaca, ali su prisutne vrste veoma raznovrsne, zavisno od porekla i geografskog regiona. Identifikacijom prisutne mikroflore čajne gljive može se pokazati tipičnost same gljive, po kojoj se razlikuje od drugih. S obzirom da je dobijanje čajnog napitka primenom čajne gljive poznato veoma dugo, kao inovacija se javlja pitanje mogućnosti dobijanja fermentisanog mlečnog napitka. U tom smislu, u radu je izvršena izolacija i identifikacija mikroflore čajne gljive, pri čemu je utvrđeno prisustvo sirćetnih bakterija Acetobacter aceti, Acetobacter pasteurianus, Gluconobacter xylinum i kvasaca koji pripadaju rodovima Saccharomyces, Candida i Kloeckera. Za dobijanje fermentisanog mlečnog napitka, primenjeni su inokulumi: fermentisani čaj, retentat dobijen ultrafiltriranjem i koncentrat dobijen uparavanjem, u mleku sa različitim sadržajem mlečne masti (0,9%,1% i 2,2%) i različitim koncentracijama (10% i 15% čajnog napitka i retentata i 1,5% i 3% koncentrata). Ispitana je sposobnost rasta sirćetnih bakterija i kvasaca u deset različitih varijanti fermentisanih mlečnih napitaka, gde je najbolja aktivnost bila u prisustvu 2,2% mlečne masti a vijabilnost sirćetnih bakterija i kvasaca pokazala se veoma dobrom u toku 15 dana čuvanja fermentisanog mlečnog napitka na 4°C. Sa mikrobiološkog aspekta, primena čajne gljive u proizvodnji fermentisanih mlečnih napitaka daje osnov za dobijanje novog fermentisanog mlečnog proizvoda, ali neophodna su dalja istraživanja sa hemijskog, tehnološkog, nutritivnog i senzornog aspekta. .