Teeseene lüofiliseerimine ja lüofiliseeritud teeseene kasutamine kombucha starterkultuurina
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Kuupäev
2021
Kättesaadav alates
03.09.2021
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Kombucha jooki toodetakse ja tarbitakse aina enam, aga endiselt ei ole välja töötatud
teeseene asemel starterkultuuri, mida oleks lihtsam säilitada, transportida ja doseerida.
Kuna üksikutest mikroobidest valmistatud starterkultuuri abil ei ole võimalik saada
autentsete omadustega kombucha jooki, siis võiks starterkultuuri valmistada lüofiliseeritud
teeseenest.
Magistritöö eesmärk on anda ülevaade teeseene süsteemist, selles esinevatest mikroobidest
ja nendevahelistest suhetest, mikroobide ja bakteriaalse tselluloosi lüofiliseerimisest ning
selgitada, kas ja kuidas mõjutab teeseene lüofiliseerimine selle kasutamist kombucha
starterkultuurina.
Lüofiliseeritud teeseene efektiivsuse hindamiseks starterkultuurina määrati bakterite,
äädikhappebakterite ja pärmseente arvukus teeseenes, lüofiliseeritud teeseeneproovides ja
lüofiliseeritud teeseente abil 14 päeva kääritatud jookides ning vaadeldi kääritatud jookide
väliseid omadusi. Kõigis katseetappides kirjeldati isoleeritud mikroobide morfoloogiat ja
identifitseeriti isoleeritud mikroobid. Lisaks uuriti erinevate krüoprotektorite (sahharoos,
glükoos, galaktoos) mõju teeseenes esinevatele mikroobidele.
Teeseene lüofiliseerimisel oli efektiivseim krüoprotektor sahharoos. Lüofiliseeritud
teeseene mikroobide arvukus oli madalam (p < 0,05) kui algmaterjalis ehk tavalises
teeseenes, kuid lüofiliseeritud teeseene abil kääritatud jookides osutus mikroobide arvukus
kõrgemaks kui lüofiliseeritud proovides. Tulemustest järeldus, et mikroobide elujõulisus
võis taastuda pärast lüofiliseerimisprotsessi. Kuna lüofiliseeritud teeseeneproovidega
kääritatud jookides puudusid käärimise tunnused, siis jõuti selgusele, et lüofiliseeritud
teeseen ei ole piisavalt efektiivne kombucha starterkultuurina kasutamiseks.
Erinevates katseetappides õnnestus proovidest isoleerida ja identifitseerida vähe mikroobe,
identifitseeritud mikroobide liigid olid varieeruvad ning selle tõttu ei ole
identifitseerimistulemuste põhjal võimalik hinnata lüofiliseeritud teeseene kasutamise
võimalikkust starterkultuurina.
Töö raames kogutud andmeid ja uusi teadmisi saab kasutada tulevastes uurimistöödes
kombucha starterkultuuri väljatöötamiseks.
Kombucha is increasingly being produced and consumed, but yet no alternative starter culture to tea fungus (SCOBY) that is easier to store, transport and dose has been developed. Since it is not possible to obtain a kombucha drink with authentic properties using a starter culture produced of individual microbes, the starter culture could be prepared from lyophilized SCOBY. The aim of this Master's thesis is to give an overview of the SCOBY system, its microbes and their relationship to each other, lyophilization of microbes and bacterial cellulose, and to determine whether and how the lyophilization of SCOBY can influence its use as a starter culture of kombucha. To evaluate the efficacy of lyophilized SCOBY as a starter culture, the number of bacteria, acetic acid bacteria and yeasts in the SCOBY, lyophilized SCOBY and beverages fermented by lyophilized SCOBYs for 14 days was determined and the external properties of fermented beverages were observed. In all experimental steps, the morphology of the isolated microbes was described and the isolated microbes were identified. In addition, the effect of different cryoprotectants (sucrose, glucose, galactose) on microbes in SCOBY was studied. Sucrose proved to be the most effective cryoprotectant for lyophilization of SCOBY. The microbial count in lyophilized SCOBY was lower (p < 0,05) than that of the SCOBY, but the number of microbes was higher in beverages fermented by lyophilized SCOBY than in the lyophilized samples. The results showed that microbial viability could be restored after the lyophilization process. As beverages fermented by lyophilized SCOBY samples did not show fermentation characteristics, it was concluded that lyophilized SCOBY was not effective enough to be used as a starter culture for kombucha. In the various experimental stages, only few microbes were isolated and identified from the samples, also the species of microbes identified varied, and therefore the possibility of using lyophilized SCOBY as a starter culture cannot be assessed on the basis of these identification results. However, the data and new knowledge gathered in the work can be used in future research to develop a kombucha starter culture.
Kombucha is increasingly being produced and consumed, but yet no alternative starter culture to tea fungus (SCOBY) that is easier to store, transport and dose has been developed. Since it is not possible to obtain a kombucha drink with authentic properties using a starter culture produced of individual microbes, the starter culture could be prepared from lyophilized SCOBY. The aim of this Master's thesis is to give an overview of the SCOBY system, its microbes and their relationship to each other, lyophilization of microbes and bacterial cellulose, and to determine whether and how the lyophilization of SCOBY can influence its use as a starter culture of kombucha. To evaluate the efficacy of lyophilized SCOBY as a starter culture, the number of bacteria, acetic acid bacteria and yeasts in the SCOBY, lyophilized SCOBY and beverages fermented by lyophilized SCOBYs for 14 days was determined and the external properties of fermented beverages were observed. In all experimental steps, the morphology of the isolated microbes was described and the isolated microbes were identified. In addition, the effect of different cryoprotectants (sucrose, glucose, galactose) on microbes in SCOBY was studied. Sucrose proved to be the most effective cryoprotectant for lyophilization of SCOBY. The microbial count in lyophilized SCOBY was lower (p < 0,05) than that of the SCOBY, but the number of microbes was higher in beverages fermented by lyophilized SCOBY than in the lyophilized samples. The results showed that microbial viability could be restored after the lyophilization process. As beverages fermented by lyophilized SCOBY samples did not show fermentation characteristics, it was concluded that lyophilized SCOBY was not effective enough to be used as a starter culture for kombucha. In the various experimental stages, only few microbes were isolated and identified from the samples, also the species of microbes identified varied, and therefore the possibility of using lyophilized SCOBY as a starter culture cannot be assessed on the basis of these identification results. However, the data and new knowledge gathered in the work can be used in future research to develop a kombucha starter culture.
Kirjeldus
Magistritöö
Toiduainete tehnoloogia õppekaval
Märksõnad
magistritööd, teeseene süsteem, bakteriaalne tselluloos, lüofiliseerimisprotsess, starterkultuur