FTIR-ATR Characterization of By-products from Canola Oil Processing

Currently, the meals resulting from the processing of canola seeds are mainly used as animal feed. However, the high global production of canola oil generates considerable amounts of this by-product, which has driven research aimed at finding alternative uses for its valorization. This work proposes the analysis, via FTIR, of two by-products: press cake and press cake subjected to ethanol extraction assisted by ultrasound. Canola seeds were provided by Al High Tech (Argentina). These seeds were hydrothermally pretreated in a VZ autoclave (Argentina) for 5 min at 130 °C, dried in a BGH QuickChef microwave oven to 7% moisture (dry basis), and pressed in an IMEGEN screw press (Argentina). The resulting press cake was subjected to ultrasound-assisted extraction (absolute ethanol, 57% amplitude, 60 min, 38°C, solid–solvent ratio 1:28, VCX 500 ultrasonic probe, USA). Press cake samples with and without subsequent extraction were analyzed by means of FTIR-ATR (IRXross, Shimadzu, Japan). The analysis of the spectra allowed for the identification of various bands corresponding to relevant functional groups in both samples. Bands were observed at 1031 cm⁻¹, which were attributed to C–O stretching vibrations, characteristic of polysaccharides. The signals in the region from 2920 to 2930 cm⁻¹ correspond to C–H stretching vibrations, indicative of the presence of polysaccharides. Similarly, the band registered at 1741 cm⁻¹ is related to the presence of carbonyl bonds (C=O) found in lipids, indicating the presence of residual oil. Absorptions near 1230 cm⁻¹ can be attributed to C–H bending vibrations. Finally, peaks were recorded at 3003 cm⁻¹, assigned to C=CH stretching, which may indicate the presence of proteins in the meals. These results suggest that both by-products retain relevant structural components of polysaccharides and proteins, encouraging further analysis aimed at their separation, structural characterization, study of functional properties, and promotion of their valorization in technological applications.