English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In general, there are four basic types of tea: green (not fermented), black (fermented), oolong and white tea (partially fermented). The differences among these types are in the processing technology, which is largely reflected in their chemical composition. The most influential factor that significantly affects the quality and quantity of substances (biologically active) is the processing temperature, which causes changes in the composition (isomerization and/or transformation). The present paper focuses on monitoring content of three methylxanthines - alkaloids (caffeine, theophylline and theobromine), and seven flavan-3-ols - catechins ((+)-catechin (C), (-)-catechin-3-gallate (C-3-G), (-)-epicatechin (EC), (-)-epicatechin-3-gallate (EC-3-G), (-)-epigallocatechin-3-gallate (EGC-3-G), (-)-gallocatechin (GC) and (-)-gallocatechin-3-gallate (GC 3-G)), which are characteristic for tea. Attention was also given to the assessment of selected antioxidant parameters using spectrophotometric procedures (ABTS - radical cation decolorization assay and Phosphomolybdenum reducing antioxidant power assay) in relation to the determined substances using RP-HPLC/DAD analysis. Based on the results obtained, it can be concluded that a type of tea clearly affects the quality and quantity of the substances that have a positive impact on the consumer's health, significantly reflected in the levels of antioxidant active substances determined by the spectrophotometric procedures. The highest content of methylxanthin, catechins, polyphenols and antioxidant substances was recorded in the green tea sample GT3. The highest content of flavonoids and phenolic acids was recorded in the Pu-erh tea sample PT 5.

Methylxanthines and catechines in different teas (Camellia sinensis L. Kuntze) - influence on antioxidant properties