Phenol composition and antioksidant activity of sage teas (Salvia Officinalis L.)

Svrha ovog rada bila je pratiti utjecaj načina pripreme čaja kadulje na kvalitetu čaja i ispitati kakve promjene nastaju tijekom stajanja čaja. To je provedeno praćenjem promjena u fenolnom sastavu čajeva (ukupni fenoli, flavonoidi, neflavonoidi, flavan-3-oli, hidrolizirani tanini), spektrofotometrijskim određivanjem boje čajeva, određivanjem antioksidacijske aktivnosti čajeva DPPH-metodom, kao i senzorskim ocjenjivanjem čajeva kvantitativnom deskriptativnom analizom (QDA). Također, osušeni listići kadulje podvrgnuti su analizi fizikalno-kemijskih parametara. Najveća količina fenolnih spojeva kao i najveća antioksidacijska aktivnost određena je u čajevima kod kojih su listići bili 10 i 30 minuta u kontaktu sa vodom. Nakon 30 minuta stajanja čaj je vrlo malo izgubio na kvaliteti. Nakon 60 minuta stajanja izgubila se znatna količina fenolnih spojeva i smanjila se antioksidacijska aktivnost.The purpose of this research was to monitor the influence of different sage tea preparation methods on tea quality, and to monitor the changes in tea composition that might arise during time after tea preparation. This was accomplished by monitoring changes in phenol composition of sage teas (total phenols, flavonoids, nonflavonoids, flavan-3-ols, hydrolized tannins), spectroscopic determination of tea color, determination of antioxidant activity of teas by DPPH method, as well as sensoric evaluation of teas by qualitative descriptive analysis (QDA). Also, physical and chemical parameters were measured in dried leaves of sage. The greatest amount of phenol compounds as well as the greatest antioxidant activity were determined in the teas which had 10 and 30 minute long contact with water. Quality of tea did not change significantly after 30 minutes of standing. However, the period longer than 60 minutes after preparation caused the loss of considerable amount of phenol compounds as well as decrease in the antioxidant activity