Effects of debittering on red grapefruit juice concentrate

Clarified, debittered grapefruit juice concentrate (64.2 degreesBx) was produced by membrane filtration, debittering, and an evaporation process. Debittering by an XAD-16 adsorption column removed more than 78% of bitterness in grapefruit juice, based on naringin content. Also, some of the non-bitter flavonoids, such as narirutin and hesperidin, were nearly completely removed. Other values, such as vitamin C, and total phenolics, based on absorbance at 325 run, were also reduced (P < 0.05) after debittering. The vitamin C loss can probably be attributed to juice handling during processing. Absorption spectra in the 200-450 nm region showed characteristic absorption maxima around 280 and 322 nm in the control but no spectral fine structure in debittered concentrate. Besides differences in flavonoid profile, there was a slight difference in colour. Debittered concentrate had less chroma (CIE C*) and more lightness (CIE L*) than the control. Thus, the colour of debittered concentrate could be described as slightly paler than that of the control. (C) 2003 Published by Elsevier Science Ltd.