A Comparative Study of the Analysis of Antioxidant Activities of Liquid Foods Employing Spectrophotometric, Fluorometric, and Chemiluminescent Methods

Abstract

The antioxidant profile of liquid foods is complex and includes different lipid and water-soluble compounds. These should be considered when assessing total antioxidant capacity (TAC) of these beverages, since it may act synergistically rather than individually. This study describes and compares the use of spectrophotometric methods (Trolox equivalent antioxidant capacity, TEAC and 2,2-diphenyl-1picrylhydrazyl, DPPH), fluorometric (oxygen radical antioxidant capacity, ORAC), and photochemiluminescence (PCL) for the measurement of the TAC of different liquid foods (fruit juice mixed with milk and vegetables beverage). An evaluation was also made for the influence of certain compounds (ascorbic acid, phenolic compounds, total carotenoids, and tocopherols) with antioxidant capacity that was present in the samples studied. The different methods studied allow the determination of the TAC of the analyzed foods in a precise and accurate way. The TAC values in the studied samples differ from the applied method. An overall antioxidant potency composite index was calculated by assigning each test's equal weight. When an index score was applied, ORAC method had the higher antioxidant capacity values in the analyzed liquid foods in comparison with the other methods. The correlations among the different methods used for the determination of the antioxidant capacity depend on food, that is, mainly due to compounds (lipid and water soluble) of the different food matrix. In addition, ascorbic acid was the main contributor to antioxidant capacity of fruit juice mixed with milk beverages measured with the different methods. However, in vegetables beverages, phenolic compounds were found to correlate more significantly with antioxidant capacity values.

Ultrasound-assisted extraction of bioactive compounds from lemon balm and peppermint leaves

“…The results obtained are in agreement with other literature data (İnce et al, 2013). The antioxidant activity is in correlation with the total phenolic content, vitamins, and generally bioactive compounds (Barba et al, 2010(Barba et al, , 2013CarbonellCapella et al, 2014;Criado et al, 2014). According to the results obtained in this study, a strong relationship between antioxidant activity and the content of total phenolic compounds, flavonoids, and non-flavonoids in the aqueous samples of fresh lemon balm leaves extracted with the classical and ultrasonic methods was determined ( Table 3).…”

Extraction assisted by pulsed electric energy as a potential tool for green and sustainable recovery of nutritionally valuable compounds from mango peels

“…The sample was incubated for 30 min at room temperature (T = 20°C). Absorbance, A, was measured at the wavelength of 515 nm (Barba, Esteve, Tedeschi, Brandolini, & Frígola, 2013). Relative antioxidant capacity (R AC ) was evaluated as…”

Role of Potassium Permanganate Ethylene on Physicochemical Properties, during Storage of Five Different Tomato Cultivars

“…Oxalic acid (9.5 mL) 1% (w/v) and 2 mL of acetic acid/sodium acetate 2 M buffer (pH=4.8) were added to an aliquot of 0.5 mL of filtrate, and the solution was transferred to the polarographic cell. The following instrumental conditions were applied: DP50, mode DME, drop size 2, drop time 1 s, scan rate 10 mVs-1, initial potential -0.10 V. Determinations were carried out by using the peak heights and standard additions method [24].…”

“…The solution was diluted with ethanol until an absorbance of 0.70 was reached at 734 nm. Once the radical was formed, 2 mL of ABTS•+ was mixed with 100 μL of appropriately diluted sample and the absorbance was measured at 734 nm for 20 min in a Perkin Elmer UV/ Vis Lambda 2 spectrophotometer (Perkin-Elmer, Jügesheim, Germany) in accordance with Barba et al [24].…”

“…The reaction was performed at 37 °C as the reaction was started by thermal decomposition of AAPH in 75 mM phosphate buffer (pH 7.0). The final reaction tested and the concentrations of the different reagents were determined following Barba et al [24].…”