Influence of peptide and amino acids on the formation of cheese flavour

U sirevima se tijekom zrenja odvijaju kompleksne mikrobiološke i biokemijske promjene koje imaju značajan utjecaj na formiranje organoleptičkih karakteristika gotovog proizvoda. Proteolitički enzimi razgrađuju kazein do većih i manjih peptida te slobodnih aminokiselina. Količina i omjeri pojedinih aminokiselina i topljivih peptida znatno utječu na teksturu i organoleptička svojstva sira. Razgradnjom aminokiselina u siru nastaju alkoholi, aldehidi, esteri, kiseline i sumporni spojevi koji formiraju specifične arome raznih vrsta sireva. U siru je identificirano više od 200 različitih hlapljivih komponenti. Okus sira je koncentriran u frakciji topljivoj u vodi (peptidi, aminokiseline, organske kiseline i amini), dok je aroma uglavnom koncentrirana u hlapljivoj frakciji (organske kiseline, aldehidi, amini, esteri). Mnogi sirevi sadrže iste ili slične komponente, ali u različitim koncentracijama i odnosima. Posebnosti arome sira ne zasnivaju se samo na jednom specifičnom spoju već na kombinaciji različitih spojeva nastalih tijekom zrenja. Djelovanjem na proteolitičke procese može se ubrzati i modificirati tehnološki proces proizvodnje sira, te ih se stoga intenzivno proučava.Complex microbiological and biochemical changes take place during cheese ripening process, having a significant impact on the formation of organoleptic characteristics of the final product. Proteolytic enzymes degraded casein to larger and smaller peptides and free amino acids. The quantity and the ratios of particular amino acids and soluble peptides significantly influence the texture and organoleptic properties of cheese. The products of amino acid degradation in cheese are alcohols, aldehydes, esters, acids and sulphur compounds, which form specific aromas of various cheese types. More than 200 different volatile components have been identified in cheese. Cheese flavour is concentrated in the watersoluble fraction (peptides, amino acids, organic acids and amines), while aroma is mainly concentrated in the volatile fraction (organic acids, aldehydes, amines, esters). Many cheeses contain the same or similar components, but in different concentrations and ratios. Specific characteristics of cheese aroma are not based only on one specific compound, but on combination of different compounds produced in the maturing process. The technological process of cheese production can be accelerated and modified by influencing proteolytic processes, which are therefore the subject of intense research