magistrsko delo
Saša Tompa (Author), Darja Pečar (Mentor), Andreja Goršek (Co-mentor)

Abstract

Kefirna zrna so kljub bogati raziskovalni zgodovini še vedno zanimiva alternativa za raziskovanje na različnih področjih. Dandanes se še posebej pogosto ukvarjamo z bioprodukti in zdravim načinom življenja. V magistrskem delu smo raziskovali možne načine uporabe sirotke. Predvsem nas je zanimalo, če je medij - sirotka, uporaben za množično proizvodnjo kefirnih zrn. Namen je bil določiti optimalne procesne pogoje pri procesu fermentacije sirotke z naravno starter kulturo za maksimalno prirast kefirnih zrn in poiskati kinetični model rasti kefirnih zrn in proizvodnje etanola. Kinetiko proizvodnje kefirnih zrn in etanola smo opisovali s pomočjo modificiranih Gompertz-ovih modelnih krivulj. Na podlagi pridobljenih kinetičnih podatkov lahko brez eksperimentalnega dela napovemo uporabo procesnih pogojev za proizvodnjo želene količine produkta. Ugotovili smo, da je proizvodnja kefirnih zrn odvisna od temperature, saj le-ta z poviševanjem temperature narašča. Na podlagi dobljenih kinetičnih parametrov in modelov za opis kinetike rasti kefirnih zrn smo določili najprimernejše procesne parametre za maksimalno masno koncentracijo kefirnih zrn. Pri temperaturi 28 ºC in vrtilni frekvenci mešala 100 min-1 smo dobili maksimalno koncentracijo kefirnih zrn, Δγkz,max = 8,4 g/L. V drugem delu naše naloge smo določali kinetiko proizvodnje produkta fermentacije, etanola. V tem primeru smo določili vrednosti dveh ključnih optimalnih procesnih parametrov za proizvodnjo etanola, to sta temperatura, ϑ = 28 ºC in vrtilna frekvenca mešala, fm = 100 min-1. Pri teh pogojih smo dobili masno koncentracijo etanola γEtOH,m = (18,5 ± 0,1) g/L, z modelom izračunana vrednost je bila, γEtOH,max = (20,6 ± 0,7) g/L. S tem smo dokazali, da je sirotka primeren medij za množično proizvodnjo kefirnih zrn in je proizvodnja primerljiva z medijem mleko.

Keywords

fermentacija;sirotka;kefir;reaktorski sistem;spektrofotometrija;kefirna zrna;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [S. Tompa]
UDC: 577.31:543.94(043.2)
COBISS: 21797654 Link will open in a new window
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Downloads: 126
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Other data

Secondary language: English
Secondary title: Microbiological kinetics of natural starter culture growth in whey
Secondary abstract: Kefir grains, despite their rich research history, are still interesting alternative to research in various fields. Nowadays, we often deal with bioproducts and a healthy lifestyle. This work explores possible ways of using whey. In particular, we were interested whether the whey is useful for the mass production of kefir grains. The goal of the thesis was to establish optimal conditions for the fermentation of whey by a starter bacteria culture for maximum growth of kefir grains and to find kinetic growth model of kefir grains and the production of ethanol. The kinetics of the production of kefir grains and ethanol were described using Gompertz modelling curves. Based on the kinetics results obtained we were able to predict the process parameters for the desired amount of the final product, without resorting to experimental work. We discovered that the production of kefir grains depends on the temperature and is proportional to its increase. From the obtained kinetics parameters and models for the description of the growth of kefir grains, we determined optimal process parameters to be a temperature of 28 °C and a speed of mechanical stirrer of 100 rotations/minute. With these, we achieve the highest mass concentration of kefir grains, at Δγkz, max = 8.4 g/L. The second part of the thesis was focused on determining the kinetics of the production of ethanol, the product of fermentation. In this case, we determined the values of two key optimal process parameters for the production of ethanol, i.e. temperature, of 28 °C and a speed of stirring of 100 rpm. These parameters result in maximum mass concentration γEtOH,m = (18.5 ± 0.1) g/L, calculated with Gompertz model was γEtOH,max = (20.6 ± 0.7) g/L. Based on these result we conclude that whey is a suitable medium for mass production of kefir grains. We also conclude that production with medium whey is comparable to production with medium milk.
Secondary keywords: fermentation;kefir grains;reaction system;spectrofotometry;Gompertz model;
URN: URN:SI:UM:
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: XIV, 71 str.
ID: 10960116