Determination of Biological and Sensory Profiles of Biscuits Enriched with Tea (Camellia sinensis L.) Powder

The aim of this work was to characterise the biological and sensory profile of biscuits enriched with green (1 and 3%) and black tea (1 and 3%) powders. Biscuits without the addition of tea were used as a control. Phenolic concentration, flavonoid concentration, and antioxidant activity were determined spectrophotometrically. Amino acid composition was determined using automatic amino acid analyser AAA 400 and crude fibre content using an Ancom analyser. Sensory profiles were evaluated by comparison of enriched and control biscuit samples. The enriched biscuits showed higher phenolic and flavonoid concentration and antioxidant activity estimated by DPPH and phospholybdenum method in comparison with levels in the control group. The best results for antioxidant activity estimated by DPPH and phosphomolybdenum methods were achieved in biscuits enriched with black tea powder (3%): 2.25 and of 32.64 mg TEAC·g⁻¹, respectively. Total phenolic concentration was 1.16 mg GAE·g⁻¹, and total flavonoid concentration was 0.13 mg QE·g⁻¹. These biscuits had higher concentration of crude fibre in comparison with the control group and the highest concentration (0.64%) was found in biscuits with addition of 3% green tea powder. The amino acid composition in samples, including in the control sample was balanced, with slightly higher concentration of threonine, serine, and methionine in enriched samples, but this parameter was not statistically significant. Biscuits enriched with green and black tea had higher sensory scores for taste, smell and aftertaste.