Bioactive Compounds and Antioxidant Capacity in Freeze-Dried Red Cabbage by FT-NIR and MIR Spectroscopy and Chemometric Tools

Abstract

Red cabbage is a widely consumed vegetable worldwide due to its popularity and affordability. This vegetable has a significant content of bioactive compounds known for their antioxidant properties. Several traditional methodologies are commonly used to measure the total phenolic and anthocyanin content (TPC and TAC) and the antioxidant capacity. However, these methods generate toxic waste, pose a threat to the operator, and are time-consuming. This study determined the potential use of near and mid-infrared (NIR and MIR) spectroscopy, along with chemometric tools to evaluate TPC, TAC, and antioxidant capacity in red cabbage. The PLS models obtained by MIR to predict TAC (RMSEP = 0.35 mg/g), TPC (RMSEP = 0.34 mg GAEq/g), oxygen radical absorbance capacity (ORAC) (RMSEP = 125.31 μMol Eq trolox/g), and trolox equivalent antioxidant capacity (TEAC) (RMSEP = 0.33 μMol Eq trolox/g), and 2,2-diphenyl-picrylhydrazyl (DPPH) (RMSEP = 11.11 μMol Eq trolox/100 g) displayed good parameters of errors of prediction. Models constructed with NIR to predict TAC (RMSEP = 0.47 mg/g), TPC (RMSEP = 0.41 mg GAEq/g), ORAC (RMSEP = 116.34 μMol Eq trolox/g), TEAC (RMSEP = 0.29 μMol Eq trolox/g), and DPPH (RMSEP = 11.47 μMol Eq trolox/100 g) had similar results. These results suggest that the vibrational spectroscopic techniques of NIR and MIR associated with chemometrics could be successfully used for determination of TAC, TPC, and antioxidant capacity. They are sustainable and efficient methods that reduce toxic waste and time when compared to current protocols.