| Popis: |
V okviru raziskave za diplomsko delo smo določali vsebnost antioksidantov v mlevskih frakcijah treh sort ječmena. Ječmen smo zmleli na mlinski kamen in sejali skozi sito (124 ?m). Večjo frakcijo smo ponovno zmleli in sejali skozi sita velikosti 124 ?m, 140 ?m in 250 ?m. Iz mok, ki so predstavljale posamezne frakcije, smo ekstrahirali antioksidante in določili njihovo vsebnost s prostima radikaloma DPPH in ABTS ter s Folin-Ciocalteujevim reagentom. Rezultate smo izrazili kot ekvivalent Troloksa, s katerim smo pripravili umeritvene krivulje. Iz dobljenih rezultatov lahko sklepamo, da se mlevske frakcije zelo razlikujejo v vsebnosti antioksidantov. V splošnem velja, da je vsebnost antioksidantov najmanjša v frakcijah z najmanjšimi delci. Ugotovili smo tudi, da se relativna vsebnost antioksidantov v posameznih frakcijah plevnatega in golega ječmena razlikuje. Pri slednjem smo ugotovili, da je največja vsebnost antioksidantov v frakciji z največjimi delci, medtem ko za obe sorti plevnatega ječmena velja, da največ antioksidantov vsebujeta moki z velikostjo delcev med 140 in 250 ?m. Within the research for the bachelor thesis, we evaluated the content of antioxidants in the milling fractions of three cultivars of barley. We milled the barley and sifted the flour through the first sieve (124 ?m). We milled the bigger fraction again and sifted it through sieves of sizes 124 ?m, 140 ?m and 250 ?m. Out of the flours, which represented different fractions we extracted the antioxidants and determined their content with free radicals DPPH and ABTS and with Folin-Ciocalteu reagent. The contents of antioxidants were determined from the standard curves, made with Trolox and expressed as Trolox equivalents. The results reveal that different fractions contain a vastly different amount of antioxidants. In general, the content of antioxidants in the fractions with smallest particles was the lowest. We found out that the distribution of antioxidants in the particular fractions of hulled and hull-less barley is different. For hull-less barley, the largest antioxidant content was found in the fraction with the largest particles, while the fraction with particle size between 140 ?m and 250 ?m was the richest source of antioxidants for both hulled barleys. |
