Screening of changes in content of health benefit compounds, antioxidant activity and microbiological status of medicinal plants during the production of herbal filter tea

Abstract During the production of fine cuts in tea factory difference in the content of essential oil in investigated raw and investigated processed plant material was detected. The content of essential oil in Melissa officinalis fine cut, in comparison to the content measured in raw material, has been decreased for 13.0%. Content of total phenols in investigated plant materials (raw and fine cuts) varied from 3.2096 mg GAE/g to 177.6038 mg GAE/g. Industrial processing affected on the content of total phenols, lower was measured in produced fine cuts in comparison to raw materials. All vitamin C was lost during the production of Cassia angustifolia and Mentha piperita fine cuts. Investigated samples were of satisfactory microbiological quality due to the presence of Salmonella spp. (not detected in 25 g of analyzed plant material) and E. coli (