Electrochemical and Spectrophotometric Methods for Polyphenol and Ascorbic Acid Determination in Fruit and Vegetable Extracts

Abstract

Research background. Fresh-cut fruits and vegetables are considered sources of antioxidant compounds. However, their shelf life is limited due to nutritional, quality and safety deterioration. Therefore, in recent decades, various methods have been reported for food processing and preservation, as well as for the determination of antioxidant compounds, due to their many benefits when consumed. The aim of the present work is to compare the performance of electrochemical and spectrophotometric methods in the analysis of the content of polyphenolic compounds and ascorbic acid in extracts from fruits (eggplant), edible roots (carrot) and leaves (rocket, lettuce and chard), and evaluate their capability to detect small changes in the antioxidant content in the eggplant extracts previously irradiated with different UV-C light intensities. Experimental approach. Polyphenolic compounds and ascorbic acid were determined by electrochemical and spectrophotometric methods. An enzymatic biosensor and a nanocomposite sensor were used for polyphenolic compounds and ascorbic acid, respectively, in electrochemical measurements, while Folin-Ciocalteu and Kampfenkel methods were used for spectrophotometric measurements. Results and conclusion. Results obtained through the different methodologies were comparable and consistent with each other. Both methods allowed determining the content of ascorbic acid and polyphenolic compounds in the fruit and vegetable extracts. Moreover, both techniques enable the detection of the analyte concentration changes in samples exposed to different UV-C intensities and storage days. Finally, it was observed that the antioxidant capacity depends on the type of food, treatment and storage period. Novelty and scientific contribution. Both methodologies were suitable for the quantification of analytes; however, the electrochemical sensors provided higher specificity and selectivity, applicable to different fruit and vegetable matrices, obtaining results with higher precision, in shorter time and with a smaller sample volume, minimizing the economic costs because of the lower consumption of reagents.

Immobilization of Horseradish Peroxidase onto Montmorillonite/Glucosamine–Chitosan Composite for Electrochemical Biosensing of Polyphenols

“…The sensitivity and reusability of the biosensor were analyzed. The average values of sensitivity of the three independent measurements; the coefficient of variation of the sensitivity; and the linear range were (0.220 ± 0.002) mA mM −1 , 9%, (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) µM and (0.190 ± 0.001) mA mM −1 , 5%, (1-9) µM for the 4:1 and 20:1 composites, respectively. Both composites were used five days after their preparation to modify electrodes and to adsorb HRP from the fresh protein solution.…”

“…In this regard, electrochemical biosensors represent an excellent alternative with advantages such as rapid response, specificity, minimal sample preparation, and less expensive equipment [5].…”

“…However, these methodologies require laborious preliminary stages for sample conditioning and expensive equipment and reagents. In this regard, electrochemical biosensors represent an excellent alternative with advantages such as rapid response, specificity, minimal sample preparation, and less expensive equipment [ 5 ].…”

Optimization of the Extraction Conditions of Antioxidant Phenolic Compounds from Strawberry Fruits (Fragaria x ananassa Duch.) Using Response Surface Methodology

“…These substances possess many advantages including anti-aging and anti-inflammatory. Additionally, it has been suggested that they could be useful for the prevention of several chronic and neurodegenerative disorders (Zehiroglu and Ozturk Sarikaya 2019;Tulli et al 2020;Minutti-López Sierra et al 2019). Berry fruits play a significant role in human nutrition and provide numerous health benefits because of their high nutrient content, which includes vitamins, minerals, and bioactive components such polyphenolic phytochemicals (Olas 2018;Golovinskaia and Wang 2021;Cosme et al 2022).…”