Vpliv vsebnosti CO2 in procesnih pogojev na potek fermentacije in senzorične lastnosti kombuče

magistrsko delo

Špela Habjanič (Author), Andreja Goršek (Mentor), Darja Pečar (Co-mentor)

Abstract

Kombuča je osvežilna fermentirana pijača, bogata z organskimi spojinami, polifenoli, vitamini, minerali ter drugimi bioaktivnimi snovmi. Prvotno izhaja iz območja na severovzhodu Kitajske, v zadnjih letih pa je doživela pravi razcvet po vsem svetu. V okviru magistrskega dela smo študirali potek fermentacije sladkanega čaja s kombučo. Zanimala nas je dinamika koncentracije sladkorja, CO2 in etanola med procesom fermentacije ter gibanje pH vrednosti. Raziskovali smo vplive izbranih bioprocesnih parametrov na kvaliteto končnega napitka. V nadaljevanju smo opazovali vpliv temperature na potek fermentacije. Za določitev bioprocesnih parametrov smo uporabljali tekočinsko kromatografijo visoke ločljivosti in aparat za merjenje koncentracije raztopljenega CO2. V prvi fazi je proces fermentacije potekal v 6 L steklenih posodah, primarna fermentacija je potekala teden dni. Nato smo pri procesu sekundarne fermentacije uporabili 100 mL stekleničke. Sekundarna fermentacija je trajala dober mesec dni. V splošnem smo potrdili, da vrednosti pH in sladkorja med procesom fermentacije padajo, koncentracije CO2 ter etanola pa naraščajo. Ugotovili smo, da dodatek sirupa h kombuči pospeši proces sekundarne fermentacije, saj v krajšem obdobju nastane bolj kisla, gazirana pijača z večjo vsebnostjo alkohola. Po drugi strani pa umetno dodan CO2 h kombuči zaustavi oziroma upočasni proces fermentacije, predvsem v prvi fazi procesa (prvih 14 dni). Z rezultati smo potrdili, da ima temperatura pomembno vlogo pri procesu fermentacije. Pri višji temperaturi (35 °C) je fermentacija potekala hitreje, vrednosti pH in sladkorja so hitreje padale, koncentracije CO2 in etanola pa naraščale, v primerjavi s potekom sekundarne fermentacije pri sobni temperaturi (24 °C). Nasprotno smo opazili pri fermentaciji kombuče, ki je potekala v hladilniku (5 °C). Nižje temperature fermentacije so proces upočasnile. Nazadnje smo ugotovili, da na proces fermentacije močno vplivajo uporabljena starter kultura, njena oblika, velikost, izvor in starost.

Keywords

kombuča;SCOBY kultura;sekundarna fermentacija;CO2;etanol;temperaturna odvisnost;magistrske naloge;

Data

Language:	Slovenian
Year of publishing:	2023
Typology:	2.09 - Master's Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[Š. Habjanič]
UDC:	637.136.5(043.2)
COBISS:	152285955
Views:	92
Downloads:	19
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	The effect of CO2 content and process conditions on fermentation course and sensory properties of kombucha
Secondary abstract:	Kombucha is a refreshing fermented drink rich in organic compounds, polyphenols, vitamins, minerals and other bioactive substances. It originally comes from an area in the northeast of China, but in recent years it has experienced a real boom all over the world. As part of our master's thesis, we studied the fermentation process of sweetened tea with kombucha. We were interested in the dynamics of the concentration of sugar, CO2 and ethanol during the fermentation process. We were also interested in the movement of the pH value. We investigated the effects of selected bioprocess parameters on the quality of the final beverage. Next, we observed the influence of temperature on the course of fermentation. We used the high-performance liquid chromatography and the Mettler Toledo apparatus to determine bioprocess parameters. In the first phase, the fermentation process took place in 6 L glass containers throughout the course of the primary fermentation period, which is one week. Then we used 100 mL bottles in the secondary fermentation process. The secondary fermentation lasted for a good month. In general, we confirmed that pH and sugar values decrease during the fermentation process, while CO2 and ethanol concentrations increase. However, we found that the addition of syrup to kombucha speeds up the secondary fermentation process, as a more acidic, carbonated drink with a higher alcohol content is produced in a shorter period of time. On the other hand, artificially added CO2 to kombucha stops or slows down the fermentation process, especially in the first phase of the process (the first 14 days). The results confirmed that temperature plays an important role in the fermentation process. At a higher temperature (35 °C), the fermentation proceeded faster, pH and sugar values decreased faster, and CO2 and ethanol concentrations increased, compared to the course of the secondary fermentation at room temperature (24 °C). The opposite was observed in kombucha fermentation that took place in the refrigerator (5 °C). Lower fermentation temperatures slowed down the process. Finally, we found that the fermentation process is strongly influenced by the starter culture that is used, its shape, size, origin and age.
Secondary keywords:	kombucha;SCOBY culture;secondary fermentation;CO2;ethanol;temperature dependence;
Type (COBISS):	Master's thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	1 spletni vir (1 datoteka PDF (XI, 73 f.))
ID:	18467780