Application of chemometric methods in the evaluation of antioxidants activity from degreased chia seeds extracts

Samples of chia seeds (Salvia hispánica L.) were degreased by cold pressing and the residue obtained named degreased chia seeds (DCS) had the antioxidants extract obtained. A 22 experimental design was employed in order to evaluate the factors ethanol concentration and extraction time. The optimized conditions were extraction time 15 min with ethanol 70% where the activity (RSA), evaluated by the DPPH (2,2-diphenyl-1-picryl-hydrazyl) method was 94.76%. For this extract, the total phenolics content was 359.64 mg EGA/100 g. A pseudo-univariate calibration model is proposed as an alternative methodology to determine the %RSA by using the relative concentration from multivariate curve resolution with alternating least squares (MCR-ALS) from near-infrared (NIR) spectra of the antioxidant extract from DCS. The results suggest the possibility of %RSA determination directly from NIR spectra from extracts from DCS by using the multivariate resolution method MCR-ALS.