2.5. Analysis of antioxidants: ascorbic acid, a-tocopherol, b-carotene and lutein For the determination of the antioxidants in the A. unedo fruit, digestion and fermentation samples, high-performance liquid chromatography (HPLC) coupled to photodiode-array detector (DAD) (Waters, Milford, MA) was used. The HPLC-DAD system included a Waters 600 E pump, a Waters column heater (column temperature 22 C), a Waters 717 Plus autosampler and a Waters 996 DAD detector. Empower software was used. Before injection, all the samples were filtered with a 0.22 lm nylon syringe filter. All the compounds were quantified by their own calibration curves.