Optimizacija fermentacije sladke sirotke

magistrsko delo

Neža Miklavič (Author), Barbara Jeršek (Reviewer), Andreja Čanžek Majhenič (Mentor)

Abstract

Sladka sirotka, stranski proizvod pri proizvodnji sira, je vir najkakovostnejših biološko visokovrednih sirotkinih proteinov, hkrati pa zaradi dnevno proizvedenih ogromnih količin velik ekološki in ekonomski problem tako z vidika izkoriščanja kot odstranjevanja. Prav zato je sirotka še vedno pomemben predmet raziskav pri iskanju novih možnosti njenega izkoriščanja. Namen naloge je bil optimizirati fermentacijo sladke sirotke s pomočjo mlečnokislinskih bakterij ter kombinacije mlečnokislinskih bakterij in kvasovk v stabilen in senzorično sprejemljiv napitek. Uporabili smo petnajst različnih komercialnih starterskih kultur, jih cepili v vzorce pasterizirane sirotke in spremljali potek fermentacije posameznega vzorca z mikrobiološko analizo in merjenjem vrednosti pH v določenih časovnih intervalih. Poskus fermentacije sirotke smo ponovili z uporabo enakih starterskih kultur, pri čemer smo ob cepitvi vzorcev sirotke s starterskimi kulturami dodali še encim laktazo za hidrolizo laktoze. Po obeh fermentacijah je panel 6-ih preskuševalcev vzorce senzorično ovrednotil. Na podlagi rezultatov senzorične analize smo nato iz obeh skupin izbrali po 3 najbolje ocenjene izdelke, ponovno izvedli fermentacijo in hidrolizo. Izdelke smo nato ustrezno shranili ter z mikrobiološko in senzorično analizo 24 dni spremljali njihovo kakovost in na podlagi rezultatov postavili optimalen rok trajanja. Izbranim šestim vzorcem smo okus obogatili še s sadnimi pripravki iz sliv, hrušk ali jabolk. Najboljše senzorične ocene so imeli napitki z dodatkom svežih ali sušenih jabolk. Na koncu smo izbirali izdelek, ki je izkazoval ustezno stabilnost in senzorično kakovost. To je bila sirotka, ki smo jo fermentirali s startersko kulturo ABY-3 ter hidrolizirali z dodatkom encima laktaze. Na podlagi rezultatov senzorične analize s sadnimi pripravki pa bi jo obogatili s sadnim pripravkom iz svežih jabolk.

Keywords

sirotka;fermentacija;fermentirana sirotka;starterske kulture;hidroliza laktoze;laktaza;mikrobiološka analiza;senzorične lastnosti;

Data

Language:	Slovenian
Year of publishing:	2018
Typology:	2.09 - Master's Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[N. Miklavič]
UDC:	637.344:637.146:579.67:543.9
COBISS:	4906104
Views:	217
Downloads:	208
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Optimization of sweet whey fermentation
Secondary abstract:	Sweet whey, a by-product at cheese production, is a source of whey proteins with remarkable high biological value and of the highest quality. At the same time, due to the large quantities produced daily, whey is a great ecological and economic problem in terms of its exploitation and disposal. Therefore, whey is still an important topic of the researches to find novel approaches of its exploitation. The aim of our study was optimization of sweet whey fermentation with lactic acid bacteria solely and with lactic acid bacteria combined with yeasts to obtain stable and sensory acceptable product. We used fifteen different commercially available starter cultures which were inoculated to the samples of pasteurized whey. The course of fermentation was monitored by microbiological analysis and pH measurement at certain time intervals. Whey fermentation was repeated by using same starter cultures, when concomitantly with starter cultures inoculation, the lactase enzyme was added to hydrolyze lactose. After both fermentations were acomplished, a panel of 6 sensory evaluators analyzed the samples. From the results of sensory analysis, we selected 3 best-rated samples from each group and repeated the fermentation and hydrolysis. After, the products were properly stored for 24 days and their quality throughout storage period was monitored by microbiological and sensory analysis. Results enable to set the optimum shelf life. Further, fruit preparations made of plums, pears, and apples were added to the selected 6 samples. At the end, we were able to select the product which has shown the best stability and sensory quality. This was a sample of whey, which we have fermented with starter culture ABY-3 and hydrolyzed by enzyme lactase. Due to the results of sensory analysis of the samples with different fruit preparations we would enrich it with a fruit preparation of raw apples.
Secondary keywords:	whey;fermentation;fermented whey;starter cultures;lactose hydrolysis;lactase;microbiological analysis;sensory characteristics;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Biotehniška fak., Oddelek za živilstvo
Pages:	XII, 56 f., [3 ] f. pril.
ID:	11005311