Utilization of microscopic and macroscopic characteristics as part of quality control of herbal teas and tea mixtures and authentication of individual components

Abstract

Herbal teas are preparations that are used for the treatment of mild forms of various diseases, and the quality of these products is of great importance. One of the first checkpoints during quality control of tea involves microscopic and macroscopic control of tea mixtures, which is based on observation and descriptions of the morphology of plant parts in tea mixtures. Quality parameters that rely on microscopic and macroscopic methods (such as adulteration identification, determination of the degree of foreign impurities and authentication) can be easily established, and were shown to be rapid, economically viable and reliable. The main aim of the present study was to point out the importance of utilization of plant cytology, histology and organ morphology in the process of determining the quality level of tea mixtures. In this study, five samples of commercially available tea mixtures were analyzed by means of micro- and macroscopy-based methods, with the aim of content determination, as well as analysis of foreign matter content. Only one of the samples was analyzed for foreign matter content, which was possible due to the properties of the sample (grinding degree). These methods included observation of plant structures with the help of magnifying agents, in order to confirm the presence of plant species in commercial tea mixtures. The obtained results show that four out of five of the analyzed samples contained the herbal drugs listed on the declaration. The degree of foreign impurities in Sample No. 5 (the only one subjected to foreign matter analysis), was 10.4%, which exceeds the allowed limits. The results from this study show that botanical expertise is important during quality control of different raw herbal products, and macro- and micromorphological characteristics represent an important parameter for quality control of these tea mixtures.