Analytical Assessment of Bioelements in Various Types of Black Teas from Different Geographical Origins in View of Chemometric Approach

Comprehensive applications of metabolomics on tea science and technology: Opportunities, hurdles, and perspectives

With the development of metabolomics analytical techniques, relevant studies have increased in recent decades. The procedures of metabolomics analysis mainly include sample preparation, data acquisition and pre-processing, multivariate statistical analysis, as well as maker compounds' identification. In the present review, we summarized the published articles of tea metabolomics regarding different analytical tools, such as mass spectrometry, nuclear magnetic resonance, ultraviolet-visible spectrometry, and Fourier transform infrared spectrometry. The metabolite variation of fresh tea leaves with different treatments, such as biotic/abiotic stress, horticultural measures, and nutritional supplies was reviewed. Furthermore, the changes of chemical composition of processed tea samples under different processing technologies were also profiled. Since the identification of critical or marker metabolites is a complicated task, we also discussed the procedure of metabolite identification to clarify the importance of omics data analysis. The present review provides a workflow diagram for tea metabolomics research and also the perspectives of related studies in the future.

Effects of Fermentation Time and Type of Tea on the Content of Micronutrients in Kombucha Fermented Tea

The fermented tea beverage Kombucha is obtained through a series of biochemical and enzymatic reactions carried out by symbiotic cultures of bacteria and yeasts (SCOBY). It contains organic acids, vitamins, amino acids, and biologically active compounds, notably polyphenols, derived mainly from tea. Kombucha exhibits a range of health-promoting properties, including antioxidant or detoxifying effects. This fermented beverage is traditionally brewed with black tea, but other types of tea are used increasingly, which may have significant implications in terms of chemical composition and health-promoting effects. In this preliminary study, we investigated the content of micronutrients (manganese (Mn), copper (Cu), iron (Fe), chromium (Cr) and zinc (Zn)) by the ICP-OES method in Kombucha prepared with black, red, green and white tea at different time points of fermentation (1, 7, 14 days). It should be noted that the composition of separate ingredients such as tea, leaven or sugar has not been studied. Kombucha had the highest content of zinc-0.36 mg/L to 2.08 mg/L, which accounts for between 3% and 26% of the RDA (Recommended Dietary Allowance) for adults, and the smallest amounts of chromium (0.03 mg/L to 0.09 mg/L), which however represents as much as between 75% and 232% of the RDA. It has been demonstrated that the type of tea as well as the day of fermentation have a significant effect on the concentrations of selected minerals. Kombucha can therefore supplement micronutrients in the human diet.

Elemental Profiling of North-East Indian Tea (Camellia sinensis) by ICP-MS and Assessment of Associated Health Risk

Tea is a perennial crop that requires acidic soil for better plant growth. Due to the acidic nature of tea-growing soil, metals can be easily absorbed by tea plants from growing medium. Other anthropogenic activities are also the major contributor of element in the tea. This study provided a comprehensive database of 24 elements which were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Selected 24 elements belong to alkali metal (Li, Rb, Cs), alkaline earth metal (Be, Sr, Ba), transition metal (V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Cd, Hg), basic metal (Al, Ga, Sn, Tl, Pb), metalloid (As), non-metal (Se), and actinide (U). Total 321 drier mouth samples were collected during 2020-2021 from eight different regions (Darjeeling, Terai, Dooars, North Bank, Upper Assam, South Bank, Cachar, and Tripura) of north-east India. No inorganic mercury as well as uranium was detected in any tested tea samples. Mean concentrations of Be, As, Ga, Tl, Li, Se, Cd, Ag, Cs, V, Co, and Pb were at trace level, whereas macro-element mean concentrations were distributed in the manner of Al > Mn > Rb > Ba > Zn > Cu > Sr > Cr > Ni > Sn. Human health risk for non-carcinogenic and carcinogenic metals was also assessed for the studied elements. Hazard quotients (HQs) and hazard index (HI) values (< 1) for non-carcinogenic elements indicated no risk. The incremental lifetime cancer risk (ILCR) values for carcinogenic elements indicated no risk for As, Cd, and Pb and medium level risk for Ni. Study concluded that north-east Indian tea would not pose any health hazard.

Special Issue “Natural Plant Substances—Structural and Application Aspects: A Theme Issue in Honor of Professor Wieslaw Oleszek”

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Dietary Intake of Toxic Heavy Metals with Major Groups of Food Products-Results of Analytical Determinations

Food contains a complex matrix of various substances, including essential nutrients, non-nutritive substances, and toxins, including metals. The main purpose of the study was to evaluate the contribution of major groups of food products to an overall intake of toxic heavy metals (Cd, Pb, Hg, and Ni) using a combination of the 24-dietary recall technique, the ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) method, and chemometric tools. The obtained results reveal that there is a high potential risk of developing nephrotoxicity through the dietary intake of Pb in the case of both genders. The dietary intake determined for other elements (Cd, Hg, and Ni) was far below the limits established by European Food Safety Authority (EFSA). Principal Component Analysis (PCA) supported analytical determinations and revealed that cereals and vegetables were major contributors to a total intake of Cd (39.6 and 17.4% of the total exposure, respectively), Ni (40.4 and 19.3%), and Hg (16.8 and 19.6%), while water and beverages were major dietary sources of Pb (31% of the total daily intake). In contrast, eggs, fats and oils, and milk and dairy products provided the smallest amounts of Cd, Pb, and Ni. Despite containing high amounts of Hg, considering very low consumption, fish were not found to be an important source of this element.