Inaktivacija encimov v živilih

diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje

Laura Prša (Avtor), Mateja Primožič (Mentor), Maja Leitgeb (Komentor), Gregor Kravanja (Komentor)

Povzetek

Moka je živilo, ki ga najdemo v vsakem gospodinjstvu in jo uporabljamo za kuhanje in pečenje. Na kakovost moke med drugim vpliva tudi aktivnost encimov v njej. Encimi so naravno prisotni ali namerno dodani v živilih kot aditivi. Pri moki povzročajo oksidacijske procese. Eden od glavnih problemov, ki vplivajo na uporabo moke, je krajši rok uporabnosti zaradi vsebnosti nekaterih encimov. Med skladiščenjem moke, lipidi zlahka vplivajo na njeno obstojnost zaradi encimske hidrolize, ki jo katalizirajo lipaze. Temu sledi oksidacija, kar povzroči izgubo funkcionalnosti moke, okus in hranilne lastnosti. Čeprav smo v literaturi zasledili številne pozitivne učinke encimov na moko, pa smo se zaradi njihovih negativnih vplivov na kvaliteto moke odločili inaktivirati encime α-amilazo, lipazo, peroksidazo in proteazo, ki so prisotni v moki. Encima, ki najbolj vplivata na kvaliteto moke sta lipaza in peroksidaza. Omenjene encime v moki smo želeli inaktivirati z uporabo superkritičnega ogljikovega dioksida (SC CO2). Raziskali smo vpliv procesnih parametrov (tlak, čas izpostavitve in hitrost dekompresije) na aktivnost prostih encimov in encimov v moki. V diplomski nalogi smo omenjene encime podrobneje opisali in določili njihovo aktivnost v moki pred in po izpostavitvi v SC CO2. Prav tako smo tekom eksperimentalnega dela določili koncentracijo proteinov v moki po Bradfordovi metodi. Aktivnost encimov smo določali v beli pšenični moki. Rezultati kažejo, da je po izpostavitvi v SC CO2 preostala aktivnost α-amilaze najnižja. Za primerjavo smo določili tudi aktivnosti encimov v različnih vrstah moke. Ugotovili smo, da največ encimov vsebuje ržena moka in da je bila določena najvišja aktivnost za encim lipazo ne glede na vrsto moke.

Ključne besede

moka;encimi;amilaza;lipaza;peroksidaza;proteaza;superkritični ogljikov dioksid;diplomske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2019
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[L. Prša]
UDK:	543.645.4(043.2)
COBISS:	22605334
Št. ogledov:	1271
Št. prenosov:	274
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Inactivation of enzymes in food
Sekundarni povzetek:	Flour is a foodstuff that is found in every household and is used for cooking and baking. The quality of flour is, among other things, affected by the enzyme activity in it. Enzymes are naturally present or deliberately added into foodstuff as additives. They cause oxidation processes in flour. One of the main problems affecting the use of flour is a shorter shelf life due to the content of certain enzymes. During the storage of flour, lipids can easily affect its shelf life, due to enzymatic hydrolysis, which is catalyzed by lipases. This is followed by oxidation, which results in loss of flour functionality, tastefulness and nutritional properties. Although a number of positive effects of enzymes on flour has been observed in literature, we decided to inactivate enzymes α-amylase, lipase, peroxidase and protease, due to their negative effects on the quality of flour. Enzymes which affect the quality of flour the most are lipase and peroxidase. We wanted to inactivate the mentioned enzymes with the use of the supercritical carbon dioxide (SC CO2). The influence of process parameters (pressure, exposure time and rate of decompression) on the activity of free enzymes and enzymes in flour was researched. In the diploma thesis, the mentioned enzymes were described in detail and their activity in flour before and after exposure in SC CO2 was determined. During experimental work, we also determined the concentration of proteins in flour according to the Bradford method. The activity of enzymes was determined in white wheat flour. The results show that after exposure in SC CO2 the residual α-amylase activity is the lowest. For comparison, we also measured the activity of enzymes in different types of flours. We found that rye flour contains most enzymes and that the activity of lipase enzyme was the highest regardless of type of flour.
Sekundarne ključne besede:	flour;enzymes;amylase;lipase;peroxidase;protease;supercritical carbon dioxide;
URN:	URN:SI:UM:
Vrsta dela (COBISS):	Diplomsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	IX, 42 str.
ID:	11185213