Article Title

Monitoring Enzymatic Debittering in Grapefruit Juice by High Performance Liquid Chromatography


An HPLC method was developed for monitoring the progress of enzymatic debittering and estimating the efficiency of debitter enzymes by means of simultaneously determining the levels of the bitter flavanone naringin, its hydrolytic intermediate prunin and the tasteless product naringenin in grapefruit juice. The sample preparation was carried out by a polarity modification with anhydrous ethanol, a centrifuge step and a 0.45 μm filtration. Separation was achieved using a reverse phase C-18 column with a mobile phase comprising 30 % acetonitrile. The average recovery rates were above 88 % and the quantitative linearity ranged from 20 - 500 μg/mL for the flavanones analyzed. The conversions of naringin to prunin by α-L-rhamnosidase and prunin to naringenin by β-D-glucosidase in grapefruit juice were monitored, and the efficiency of the individual enzyme was separately evaluated. Applicability of this method in juice processing is also discussed.

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