Published in Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 20 ISSUE 1
Written by Gjore NAKOV, Nastia IVANOVA, Marko JUKIĆ, Daliborka KOCEVA KOMLENIĆ, Davor DANILOSKI, Jasmina LUKINAC

The aim of this study was to examine the opinion of tea drinkers about the type and the way the tea is prepared, as well as the knowledge of the biologically active substances contained in the black tea. Finally, the influence of the temperature and the method of preparation of black tea on its colour and content of biologically active compounds was determined. The survey found that black tea was the most consumed with 68.80% of the participants and has been also considered to be the healthiest type of tea (80.40%).Moreover, 39.50% of the respondents consumed tea once a month. Based on the results, tea has usually been prepared for a period of 5 min (74.10%) in boiling water at approximately 90⁰C (47.50%). In addition, 56.70% of the respondents believe that the black tea contains a high amount of caffeine. As the number of macerations increased, the amount of biologically active substances decreased (total polyphenols 134.93±0.04 mg GAE/mL, tannins 19.98±0.19 %, flavonoids 232.84±0.07 mg QE/g, caffeine 37.33±0.12 mg/mL and antioxidant activity 551.94±0.41 µM Trolox/g in black tea infusions prepared in 90⁰C (5 min) after first maceration and 7.53±0.01 mg GAE/mL, tannins 14.92±0.24 %, flavonoids 55.88±0.18 mg QE/g, caffeine 2.33±0.05 mg/mL and antioxidant activity 122.32±0.17 µM Trolox/g in black tea infusions prepared in 90⁰C (5 min) after third maceration. The obtained correlation (p>0.01) showed that the total polyphenols were correlated with other biologically active substances tested (tannins, flavonoids, caffeine and antioxidant activity) and L*, a* and b* colour parameters of black tea infusions.

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