Juice samples were thawed in an oven at 60°C for 5 min. This
treatment yielded the same results as thawing the juice at room temperature for
30 min. A modification of the SPE protocol previously used by He and Giusti was
used for polyphenol separation.18 200 μL of juice was diluted with 200 μL of
water (0.01% TFA) and vortexed. An Oasis C18 SPE cartridge (Waters,
Milford, MA, USA) was first washed with 5 mL of water (0.01% TFA). Then
the diluted juice sample and an additional 5 mL of water (0.01% TFA)
were added to the cartridge. The sample fraction was then collected after 10 mL
of methanol (0.01% TFA) was run through the cartridge. The final
methanolic fraction was dried under a constant flow of nitrogen gas. Samples
were reconstituted in water (2% acetic acid) for HPLC analysis.
Anthocyanins were separated from the juice using a previously developed
method19 . Briefly,
mixed mode cation-exchange SPE was used (Oasis MCX 3cc, 60mg, Waters, Milford,
MA, USA) and extractions performed using a Supelco Visiprep vacuum manifold.
treatment yielded the same results as thawing the juice at room temperature for
30 min. A modification of the SPE protocol previously used by He and Giusti was
used for polyphenol separation.18 200 μL of juice was diluted with 200 μL of
water (0.01% TFA) and vortexed. An Oasis C18 SPE cartridge (Waters,
Milford, MA, USA) was first washed with 5 mL of water (0.01% TFA). Then
the diluted juice sample and an additional 5 mL of water (0.01% TFA)
were added to the cartridge. The sample fraction was then collected after 10 mL
of methanol (0.01% TFA) was run through the cartridge. The final
methanolic fraction was dried under a constant flow of nitrogen gas. Samples
were reconstituted in water (2% acetic acid) for HPLC analysis.
Anthocyanins were separated from the juice using a previously developed
method19 . Briefly,
mixed mode cation-exchange SPE was used (Oasis MCX 3cc, 60mg, Waters, Milford,
MA, USA) and extractions performed using a Supelco Visiprep vacuum manifold.