Unique variability of tocopherol composition in various seed oils recovered from by-products of apple industry: Rapid and simple determination of all four homologues (α, β, γ and δ) by RP-HPLC/FLD

The tocochromanol profile was studied in seed oils recovered from by-products of fruit industry, five dessert and seven crab apple varieties grown in Eastern Europe (Latvia). The seed oils obtained from dessert apples were characterized by higher contents of tocopherols (191.05–379.08 mg/100 g oil) when compared to seed oils recovered from crab apples (130.55–202.54 mg/100 g oil). The predominant homologues of tocopherol in all the studied samples were α and β over γ and δ. However, seed oils recovered from the apple cultivars ‘Antej’ and ‘Beforest’ had a unique profile of four tocopherol homologues (α:β:γ:δ) 91.41:80.55:72.46:79.03 and 114.55:112.84:78.69:73.00 mg/100 g oil, respectively. A single dilution of seed oils in 2-propanol facilitated the direct use samples in the DPPH assay as well as injection into the RP-HPLC system containing a PFP (pentafluorophenyl) column, which resulted in a rapid separation of all four tocopherol homologues with excellent repeatability and reproducibility.