Orthogonal signal correction‐based prediction of total antioxidant activity using partial least squares regression from chromatograms

Abstract

The multivariate calibration methods—partial least squares (PLS), orthogonal signal correction and partial least squares (OSC‐PLS)—were employed for the prediction of total antioxidant activities of four Prunella L. species. High‐performance liquid chromatography (HPLC) and spectrophotometric approaches were used to determine the total antioxidant activity of the Prunella L. samples. Several preprocessing techniques such as smoothing and normalization were employed to extract the chemically relevant information from the data after alignment with correlation optimized warping. The importance of the preprocessing was investigated by calculating the root mean square error for the calibration set for the total antioxidant activity of Prunella L. samples. The models developed on the basis of the preprocessed data were able to predict the total antioxidant activity with a precision comparable to that of the reference 2,2‐azino‐di‐(3‐ethylbenzothialozine‐sulfonic acid) and 2,2‐diphenyl‐1‐picrylhydrazyl methods. The OSC‐PLS model seems preferable because of its predictive and describing abilities and good interpretability of the contribution of compounds to the total antioxidant activity. The contribution of individual phenolic compounds to the total antioxidant activity was identified by HPLC. Copyright © 2012 John Wiley & Sons, Ltd.

Assessment of antioxidant capacity by method comparison and amino acid characterisation in buffalo milk kefir

“…The ABTS radical scavenging activities of kefir samples were determined as described by Sahin et al . (). Kefir extract (0.25 mL), ethanol (3.75 mL) and ABTS solution (1 mL) were mixed and incubated at room temperature for 3 min.…”

“…The DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) radical scavenging activity of the kefir samples was determined using the method described by Sahin et al . (). The kefir extract (0.25 mL) was mixed with DPPH solution (0.18 mL) and stored for a 30‐min incubation in the dark.…”

The Antioxidative Capacity of Kefir Produced from Goat Milk

“…Estimation of ABTS .+ radical scavenging activity of sample was determined with ABTS method, as described in the literature [29]. The results were expressed as mg trolox equivalent (TE) per 100 mL of sample.…”

Determination of phenolic compounds profile in chestnut and floral honeys and their antioxidant and antimicrobial activities

“…The total antioxidant capacity of honey extract samples was determined with ABTS method, as described by Şahin et al (). ABTS + was produced by reacting 20 mM ABTS solution with 2.45 mM potassium persulfate solution and allowing the mixture to stand in dark at room temperature for 12–16 hr before use.…”