Flow Injection Amperometric Evaluation of Trolox Equivalent Antioxidant Capacity of Chocolates with Different Cocoa Content at a Boron-Doped Diamond Electrode

Abstract

Research background. The objective of this paper is to introduce an instrumentally simple analytical tool for determination of cocoa solids content in chocolates. This electroanalytical method is based on amperometric oxidation of all present antioxidants in chocolates at boron-doped diamond electrode (BDDE) that is integrated in a flow injection analysis (FIA) wall-jet electrode system. Experimental approach. As part of optimisation, thirteen commonly occurring antioxidants were investigated using cyclic voltammetry at BDDE in 0.1 mol/L phosphate buffer with different methanol (MEOH) content. Working parameters, such as of MeOH content, flow rate, and detection potential, were optimised. Principally, the height of the oxidation peak (current response) representing the oxidation of the sum of antioxidants (Total Antioxidant Content; TAC) was expressed as Trolox content. Results and conclusions. For analytical purpose, a linear range from 5.0 to 100 mg/L Trolox described by regression equation and characterized by correlation of determination 0.9994 was found. Obtained high positive correlation between determined values of Trolox equivalent antioxidant capacity (TEAC) and cocoa contents characterised by correlation coefficient of 0.9187 for eight randomly selected samples (one white, two milk, and five dark chocolates) confirmed the fact that cocoa solids represent the main source of antioxidants (reducing agents). Novelty and scientific contribution. The research demonstrates that TEAC values could be probably considered as additional marker of cocoa content in the chocolate analysis to commonly used theobromine (authenticity of food products). The developed FIA method could therefore serve as simple analytical tools in the food quality control.

Authentication of Cocoa Products Based on Profiling and Fingerprinting Approaches: Assessment of Geographical, Varietal, Agricultural and Processing Features

“…Among the arsenal of instrumental techniques available, infrared spectroscopy (IR) and mass spectrometry (MS) are the preferred ones ( Figure 1 a). Other detection techniques, such as nuclear magnetic resonance (NMR), spectroscopies (UV and fluorescence), electroanalytical analyses, or electronic noses, were less exploited in this field [ 20 , 21 , 22 , 23 , 24 , 25 ].…”

Fabrication of tin sulfide@functionalized carbon nanofiber composites for the electrochemical detection of the oxidative stress biomarker trolox

“…In contrast, high concentrations induce toxicity through oxidative stress. 6 As a result, some nations, including the United States, Australia, Brazil, New Zealand, the Philippines, and China, have banned the use of such antioxidants in edible items. Trolox's recommended daily intake (ADI) should not exceed 0–1.4 mg kg −1 body weight and 200 mg kg −1 foodstuffs, according to the FAO/WHO Expert Committee on Food Additives (JECFA).…”

“…According to the FAO/WHO Expert Committee on Food Additives (JECFA), the suggested daily intake of trolox should not exceed 0-1.4 mg kg À1 human body weight and 200 mg kg À1 food and beverages. [5][6][7] A number of such biomarkers in foodstuffs must be precisely determined to provide quick identification and accurate therapy. Therefore, developing comprehensive approaches to current techniques for determining trolox is important.…”