They validate a rapid and accurate method to analyze the antioxidant activity of red fruits

A research team from the IFAPA La Mojonera Center in Almería has certified a tool that detects the presence of beneficial compounds and their activity against free radicals in blueberries and raspberries

27/02/2024

A research team from the La Mojonera Center in Almería, the Institute of Agricultural and Fisheries Research and Training, the Institute of Food Science, Technology and Nutrition and the University of Valencia has developed and validated a methodology for the in situ analysis of the antioxidant activity of red fruits.

The system allows the evaluation of extracts, products and by-products of the agri-food industry that can later be included in drugs and nutritional supplements. Besides, have confirmed that chemical reactions occur that activate these benefits, which will allow exploring new developments and applications.

One of the objectives of the agri-food industry is the extraction of beneficial substances for health from different products and by-products. Among them, phenolic compounds stand out, especially flavonoids, which act favoring the body due to their high antioxidant capacity.

Direct electrode insertion

These compounds interact with free radicals, which cause many diseases, such as cancer, minimizing their effects. The method consists of the direct insertion of electrodes into the product to be studied, as if it were a thermometer. The researchers had already applied this methodology successfully in fresh fruits, confirming its easy application and precision in the results.

Within the group of flavonoids, researchers have focused on the effects of anthocyanins, a group of natural pigments responsible for the red, purple or blue color of many flowers and fruits, with recognized antioxidant and anti-inflammatory properties. «We confirm that the system not only allows analyzing the phenolic compounds present in the fruits, but also their interaction with other reactive substances that give them even greater antioxidant character," IFAPA researcher Irene Domínguez, author of the article, tells the Discover Foundation.

Action and reaction

These substances, called ROS (reactive oxygen species), are highly reactive and interact with phenolic compounds. Examples of ROS are free radicals or hydrogen peroxide, that cause cellular stress and that can lead to different diseases, such as cardiovascular diseases or cancer.

Microparticle voltammetry is an electrochemical technique, a branch of science that studies the interactions between compounds and electrical potential. It allows the analysis of solid samples and is commonly used for the detection of heavy metals. Through this procedure, the composition can be known by measuring the electric current generated by electrodes and the flow of electrons that occurs between the molecules.

This is the methodology

The methodology consists of inserting electrodes into the product to be studied, as if it were a thermometer.

The electrode system used allows studying the oxidation-reduction (redox) reactions that the compounds undergo. These reactions occur by the transfer of electrons between molecules.

The one that loses electrons is oxidized and the one that gains them is reduced. In the study, The experts demonstrated that the oxidation of each of the anthocyanins present in the sample produces an intense and well-defined current signal that is represented on a graph, called a voltammogram.

Furthermore, depending on the applied potential and in the presence of oxygen, ROS are generated that react with these substances. These results confirm the high antioxidant capacity of red fruits, and they show that the compounds responsible for it, after interacting with reactive species, can present even greater activity against free radicals.

Applications of the technique

This methodology has been successfully applied to samples of fresh tomato and blueberries, tea, as well as freeze-dried grapes, raspberries and blueberries. Its use has allowed us to characterize and distinguish different varieties and treatments, both pre- and post-harvest. «Given the high potential of the technique in the agri-food sector, currently, we continue to optimize the methodology to its application in other products of plant origin, both fresh and processed," adds the researcher.

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