Effects of the Chemical Composition on the Antioxidant and Sensory Characteristics and Oxidative Stability of Cold-Pressed Black Cumin Oils

The antioxidant capacity (AC); amounts of tocopherols, sterols, and polycyclic aromatic hydrocarbons; oxidative parameters; fatty acid composition (FAC); and sensory quality of cold-pressed black cumin oils (CPBCOs) available on the Polish market were analyzed and compared. The AC levels of the CPBCO samples were determined using four assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH = 226.8-790.1 mu mol TE/100 g), 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS = 385.9-1465.0 mu mol TE/100 g), cupric-reducing antioxidant capacity (CUPRAC = 975.3-19,823.3 mu mol TE/100 g), and Folin-Ciocalteu assays (FC = 168.1-643.7 mu mol TE/100 g). The FAC scores were typical for black cumin oil, except for the sample CPBCO4, which had a higher content of alpha-linolenic acid (C18:3 = 23.33%), pointing to possible oil adulteration. Additionally, the concentrations of total sterols (TSC = 372 mg/100 g) and tocopherols (TTC = 42.3 mg/100 g) in this sample were higher than those for other investigated oils (TSC = 159-222 mg/100 g, TTC = 1.9-10.4 mg/100 g respectively). The oxidative stability levels (IP = 8.21-37.34 h), peroxide values (PV = 21.36-123.77 meq O-2/kg), acid values (AV = 6.40-22.02 mg KOH/kg), and the sums of four specific polycyclic aromatic hydrocarbons ( n-ary sumation 4PAHs = 4.48-46.68 mu g/kg) in the studied samples differed significantly (p < 0.05). A sensory lexicon including 12 attributes was developed and applied for the sensory evaluation of oils using a quantitative descriptive analysis (QDA).