In this study the total phenolic content (TPC) and the content of heavy metals in the selected leaves of plants that athletes actively use as a supplement to a healthy diet. For analysis blackberry, raspberry and currant leaves are used.Green tea and black tea are used for comparison of characteristics. The extractive and total content of phenols in the vegetative part of berry crops are the most favorable indicators for fortifying sports nutrition products because these indicators are comparable to that of green and black tea. Berries and fruits have small antioxidant capacities, since they have high sugar content.
Materials and methods
Dried plant (blackberry, raspberries, black and green tea) leaves, fresh berries and flowers (hawthorn and chamomile) were used in the study. For analysis, a water extract was prepared for 10 minutes.Methyl alcohol used to make the extraction of substances into the solution.
Total Phenolic Content (TPC) activity
The total phenolic content was determined using the Folin–Ciocalteu reagent. This method is based on the reducing ability of phenolic compounds. Various phenolic compounds react with metal complexes of different sensitivities. The reactivity of the compound increases proportionally to the amount of free phenolic hydroxyl groups.
Determination of water-soluble extractives
The method is based on the extraction of water-soluble substances from the sample. The first stage includes boiling with a reverse refrigerator; the second stage includes assessment of the dried extract.
Analysis of heavy metals in plants
The raw materials were assessed using the MAX-GF2E spectrometer. A spectrometer is the analytical equipment designed to determine the content of chemical elements in a solid, powdery, or dissolved state.
Results
Results showed that the content of total polyphenols and water-soluble extractives in samples based on a weight of 2 g/200 ml with infusion time of 10 minutes. The total content of phenols in aqueous infusions is presented in terms of gallic acid. The samples with a high content of phenols also show a high number of water-soluble extractives and vice versa. As expected, green tea has the highest contents of phenols and extractives. The leaves of blackberries, raspberries, black tea have smaller contents. The leaves of blackberry, raspberry, and currant showed excellent results. These plants have the most favorable ratio of extractability and total phenolic content. The low level of heavy metals indicates the safety of the raw material. Due to their physical structure, plants cannot avoid adverse environmental conditions, so heavy metals can accumulate in large quantities.
Conclusion
The studies of common polyphenols in leaves can make a positive contribution to the antioxidant activity of human diet. In this work, assessed was the content of common polyphenols in plant leaves, which can be used not only as an additive to green tea, but also as a healthy food. Blackberry leaves, raspberries, currants were studied, and their characteristics were compared to those of green and black tea. The highest number of polyphenols has the green tea. Blackberry leaves contained 5.44% more polyphenolic compounds than black tea (10.78%) and less than green tea (16.24%) by an insignificant percentage. Raspberry leaves (12.32%) and black tea (10.78%) indicators had no significant differences, so they can be used interchangeably in nutrition. Blackberry and raspberry leaves have a similar composition due to their belonging to the same plant family. The obtained data state that the high content of polyphenols and high extractability of the infusions indicate a good potential of this raw material for the food industry. The relevance of the use of herbal and fruit teas is the lack of physiological caloric content, but juices and wines contribute to overeating. The negative consequences caused by alcohol consumption are also eliminated.
Reference:
Martynenko, K., Balanov, P., Smotraeva, I. and Vanchenko, O.I., 2022. Exploring the potential of total polyphenols in the leaves of berry plants for a healthy diet. In BIO Web of Conferences (Vol. 48, p. 02001). EDP Sciences.
