20.500.12556/RUL-179135 Spremljanje mikrobiološke in senzorične stabilnosti ter antioksidativnega potenciala funkcionalnega sirotkinega napitka med skladiščenjem Monitoring the microbiological and sensory stability, and antioxidant potential of a functional whey beverage during storage V magistrski nalogi smo kislo sirotko (KS), ki nastane kot stranski tok pri proizvodnji skute uporabili za izdelavo štirih funkcionalnih sirotkinih napitkov (FSN). V podjetju Arhel d.o.o., smo KS mikrofiltrirali, pasterizirali in fermentirali s kefirnimi zrni (KZ). Dobljeni produkt smo poimenovali izrabljeno gojišče (IG). Po ultrafiltraciji IG smo dobili retentat izrabljenega gojišča (IGR), ki ga nismo obdelali in permeat izrabljenega gojišča (IGP), ki smo ga uporabili za osnovo napitkov. IGP smo zmešali z ustekleničeno vodo in dodali različne sestavine. Napitke smo pasterizirali in jih polnili v pasterizirane steklenice. Končni izdelek smo skladiščili 105 dni v hladilniku, pri sobni temperaturi na svetlobi in temi. Zanimala nas je protimikrobna aktivnost IGP proti potencialno patogenim bakterijam in kemijska sestava napitkov, ki so jo ugotavljali na Inštitutu za mlekarstvo in probiotike (IML-PRO). Spremljali smo vpliv razmer skladiščenja na mikrobiološko stabilnost, ki smo jo ugotavljali na podlagi skupnega števila mikroorganizmov, kvasovk in plesni, enterobakterij, stafilokokov, Salmonella spp. in Listeria monocytogenes ter na senzorično stabilnost (motnost, prisotnost usedline, spreminjanje barve, vonja, okusa) FSN. Na začetku in koncu testiranja smo preverili vsebnost vitaminov ter spremljali spremembe vsebnosti fenolnih spojin in antioksidativne aktivnosti med skladiščenjem. Ugotovili smo, da IGP ni protimikrobno aktiven proti nobenemu od devetih indikatorskih sevov, vključenih v testiranje, pri FSN pa smo ugotovili, da se stabilnost merjenih parametrov najbolj spreminja pri skladiščenju pri sobni temperaturi in izpostavljenosti svetlobi, medtem ko je shranjevanje pri nizki temperaturi najbolj optimalno. In the master’s thesis, we used acid whey (KS), a by-product of quark production, to formulate four functional whey beverages (FSN). At the company Arhel d.o.o., the KS was microfiltered, pasteurized and fermented with kefir grains (KZ). The product was named spent growth medium (IG). After ultrafiltration of the IG, we got spent growth medium retentate (IGR), which was not further processed and spent growth medium permeate (IGP), which we used as the base for the beverages. The IGP was mixed with bottled water and supplemented with various ingredients. The beverages were pasteurized and filled into pasteurized bottles. The final product was stored for 105 days in the refrigerator, at room temperature in the light and dark. We assessed the antimicrobial activity of the IGP against potentially pathogenic bacteria and the chemical composition of the beverages, which was determined at the Institute for Dairy and Probiotics. We monitored the effect of storage conditions on microbiological stability, which was evaluated by measuring total viable counts, yeasts and molds, Enterobacteriaceae, staphylococci, Salmonella spp. and Listeria monocytogenes, as well as on sensory stability (turbidity, sediment, changes in color, smell and taste). At the beginning and end of the study, we analysed vitamin content and monitored changes in phenolic compounds and antioxidant activity during storage. We found that IGP did not show antimicrobial activity against any of the nine indicator strains included in the study. We found that the stability of the measured parameters changed the most during storage at room temperature with exposure to light and that low temperatures were the most optimal storage condition. kisla sirotka funkcionalni sirotkin napitek vpliv skladiščenja protimikrobno delovanje kemijska sestava mikrobiološka stabilnost senzorična stabilnost vitamini vsebnost fenolnih spojin antioksidativni potencial acid whey functional whey beverage storage stability antimicrobial activity chemical components microbiological stability sensory properties vitamins phenolic compounds antioxidant potential true false false [A. M. Jeras] Slovenski jezik Angleški jezik Magistrsko delo/naloga 2026-02-06 07:15:46 2026-02-06 07:15:53 2026-02-12 04:35:31 0000-00-00 00:00:00 2026 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 663:637.344:641.1:579:543.2/.9 278877 267552771 56167.pdf 56167.pdf 1 80CE3727BE1CB92047D7FFF57C2BDF2C 619f080f8b212fcedaefc78f59539a7ad1f6ed6726da98802e4df29aaab0d6eb 308bdc95-0323-11f1-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=227346 Biotehniška fakulteta 0 0 0