diplomsko delo
Eva Fatur (Author), Barbara Jeršek (Reviewer), Polona Jamnik (Mentor)

Abstract

Namen diplomskega dela je bil predstaviti pregled raziskav, ki vključujejo fermentacijo ne-mlečnih substratov s kefirjevimi zrni, predvsem sadnih sokov. Med potrošniki so vse bolj priljubljeni izdelki s pozitivnimi učinki na zdravje, visoko vsebnostjo funkcionalnih komponent ter dobrimi senzoričnimi lastnostmi. Veliko funkcionalnih izdelkov ima tudi probiotične lastnosti, vendar jih je večina mlečne osnove, kar lahko privede do težav pri uporabi le-teh pri potrošnikih zaradi laktozne intolerance, alergije na mlečne beljakovine, visoke vsebnosti maščob in holesterola ter veganskega načina prehranjevanja. Sadni sokovi lahko služijo kot dober substrat za fermentacijo s kefirjevimi zrni, ki so sestavljena iz mlečnokislinskih bakterij, kvasovk in ocetnokislinskih bakterij in opravljajo kombinirano fermentacijo. Pri pregledu literature se pri izbiri substrata največ uporablja sok granatnega jabolka, drugi sadni sokovi in mešani substrati s sirotko. Med fermentacijo pride do izboljšanja osnovnega substrata, kar je glavni namen fermentacije alternativnih substratov. Fermentiran napitek se izboljša tako s funkcionalnega kot tudi senzoričnega vidika, saj postane bolj osvežujoč zaradi nastanka CO2 in spremembe razmerja organskih kislin. Prav tako se izdelku zniža vsebnost sladkorja. Spremeni se tudi konsistenca, barva, vonj in okus. Značilne spremembe so opazne v znižanju vrednosti pH, povečanju mase kefirjevih zrn, povišanju koncentracije mlečne kisline, prav tako pa se poviša antioksidativna aktivnost napitka. Za kefirjeva zrna je značilno, da imajo protimikrobni učinek, kefiran pa prav tako deluje protibakterijsko, protiglivno in protitumorsko. Sestava fermentiranega soka se spremeni, kar se lahko pripiše tako spremembam v substratu kot tudi samim mikroorganizmom v kefirjevih zrnih.

Keywords

kefir;kefirjeva zrna;mikrobiota;fermentacija;sadni sokovi;funkcionalna živila;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [E. Fatur]
UDC: 637.146.21:637.136.5:641.1
COBISS: 5089912 Link will open in a new window
Views: 846
Downloads: 227
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Other data

Secondary language: English
Secondary title: Fermentation of fruit juices with kefir grains
Secondary abstract: The purpose of diploma work was to present an overview of research involving the fermentation of non-dairy substrates with kefir grains, mainly fruit juices. Among consumers are increasingly popular products with positive health effects, high levels of functional components and good sensory properties. Many functional products also have probiotic properties, but most are dairy based, which can be problematic for some consumers due to lactose intolerance, milk protein allergy, high fat and cholesterol content and vegan diet. Fruit juices can serve as a good substrate for fermentation with kefir grains, which are composed of lactic acid bacteria, yeast and acetic acid bacteria, and carry out combined fermentation. After reviewing literature it was established that pomegranate juice, other fruit juices and mixed whey substrates are most commonly used as substrate. During fermentation the basic substrate is improved, which is the main purpose of fermentation of alternative substrates. The fermented beverage is improved in both functional and sensory terms, as it becomes more refreshing due to the formation of CO2 and changes of organic acids ratio. It also lowers the sugar content. The consistency, color, smell and taste also change. Typical changes can be observed in the lowering of the pH value, the increase of the mass of kefir grains, the increase of the lactic acid concentration, as well as the increase of antioxidant activity of the beverage. Kefir grains are characterized by their antimicrobial effect, and kefiran also has antibacterial, antifungal and antitumor effects. The composition of the fermented juice is altered, which can be attributed to both changes in the substrate and the microorganisms in kefir grains themselves.
Secondary keywords: kefir;kefir grains;microbiota;fermentation;fruit juices;functional foods;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za živilstvo
Pages: VI, 22 f., [3] str. pril.
ID: 11217809