master's thesis
Development of a Direct Potentiometric Method for the Determination of Amylase Activity in Barley Malt

Maja Karnaš (2014)
Metadata
TitleRazvoj metode za određivanje amilaza u sladu direktnom potenciometrijom
AuthorMaja Karnaš
Mentor(s)Nikola Sakač (thesis advisor)
Abstract
Slad je produkt žitarica, najčešće ječma, koji se koristi u pićima i hrani kao podloga za fermentaciju te za dodavanje okusa. Dobiva se klijanjem ječma u kontroliranim uvjetima što omogućava sintezu enzima amilaza, koje embrio biljke koristi za razgradnju škroba. Amilaze su enzimi koji kataliziraju hidrolizu škroba na jednostavnije ugljikohidrate. U ječmu se nalaze dvije vrste amilaza, alfa i beta amilaze, koje se razlikuju po načinu razgradnje škroba. Aktivnost alfa amilaze u sladu ključni je parametar kvalitete za žitarice i brašno u prehrambenoj industriji, posebice u proizvodnji piva i fermentaciji. Također, različite koncentracije alfa amilaze koriste se za modifikaciju svojstava tijesta što uvelike utječe na kvalitetu pečenih proizvoda. U ovom je radu predložena elektrokemijska metoda za određivanje aktivnosti amilaza u sladu. Metoda je temeljena na direktnom potenciometrijskom mjerenju koncentracije trijodidnih iona oslobođenih iz škrob-trijodid kompleksa nakon razgradnje škroba pomoću amilaza iz slada. Kao detektor trijodidnih iona predložena je platinska redoks elektroda. U odnosu na druge dostupne metode, ovaj princip određivanja je jednostavan, brz, jeftin i ne zahtjeva specifične reagense i aparaturu. Rad također sadrži i metodički dio s prijedlogom pripreme za nastavni sat kemije u osnovnoj školi, uključujući i radne listiće s pokusima na temu enzimi.
Keywordsα-amylase amylase activity barley malt direct potentiometry
Parallel title (English)Development of a Direct Potentiometric Method for the Determination of Amylase Activity in Barley Malt
Committee MembersMilan Sak-Bosnar (committee chairperson)
Nikola Sakač (committee member)
Ivan Vicković (committee member)
GranterSveučilište Josipa Jurja Strossmayera u Osijeku
Odjel za kemiju
PlaceOsijek
StateCroatia
Scientific field, discipline, subdisciplineNATURAL SCIENCES
Chemistry
Study programme typeuniversity
Study levelgraduate
Study programmeChemistry
Academic title abbreviationmag.educ.chem.
Genremaster's thesis
Language Croatian
Defense date2014-10-13
Parallel abstract (English)
Malt is a grain product, mostly barley, used in beverages and foods as a basis for fermentation and to add flavour. The malt is obtained in barley grain germinating process under controlled conditions that enables the synthesis of amylase enzymes which are used later by plant embryo in order to breakdown starch molecules. Amylases are enzymes that catalyze hydrolysis of starch into smaller carbohydrate molecules. Two main subtypes of amylases can be found in barley malt, alpha and beta, that differ in the way they breakdown the starch molecules. The level of alpha-amylase in malt is a key quality parameter for grains and flour in food industry, mainly in beer production and fermentation. Furthermore, variable concentrations of alpha-amylase are used to modify dough properties, thus influencing the quality of the baked products. The proposed electrochemical method in this paper is based on direct potentiometric determination of levels of triiodide ion released from the starch–triiodide complex after starch degradation by barley malt amylases. A platinum redox electrode is proposed as a detector of triiodide ions. When compared to other available methods, this principle is simple, rapid, inexpensive and doesn't require specific reagents and apparatus. In the teaching part of the thesis a preparation lecture on enzymes for the elementary school chemistry class is proposed. The lecture includes some relevant experiments, questionnaires and handouts.
Parallel keywords (Croatian)α-amilaza amilazna aktivnost direktna potenciometrija ječmeni slad
Resource typetext
Access conditionOpen access
Terms of usehttp://rightsstatements.org/vocab/InC/1.0/
URN:NBNhttps://urn.nsk.hr/urn:nbn:hr:182:788167
CommitterSanda Hasenay