Reduction of bitterness and acidity in grapefruit juice by adsorptive processes

Abstract

By choosing an appropriate adsorbent, the bitter principles (naringin and limonin) and titratable acids could be removed from grapefruit juice in varying combinations.For example, Amberlite XAD-7 removed about 63 : < naringin, 85 % limonin and 3 % titratable acids and Deacidite-FFIP removed about 20% naringin, 8 % limonin and 23 0 , ; titratable acids when contacted for 1 h with grapefruit juice at the rate of 20 g (dry wt) of adsorbent per litre of juice. Such treatments, applied consecutively, would eliminate excessive bitterness and acidity from juices containing up to 2 g naringin and 36 mg limonin litre-1 and with a total soluble so1ids:titratable acid ratio of > 6 . The adsorbents are readily available, may be used as supplied and can be reactivated simply and economically; some of them have already been approved for use with foods, and such approval seems possible for the others.

Effect of various pretreatment methods on permeate flux and quality during ultrafiltration of mosambi juice

“…Clarified juices can be used in different products such as cocktails of clarified juices, liqueurs, fizzy beverages, flavoured mineral waters, etc. Juice clarification is an essential step before other specific treatments such as removing polyphenolic compounds, bitterness, tartness and acids with adsorbent resins (Carabasa, Ibarz, Garza, & Barbosa, 1998;Johnson & Chandler, 1982;Lue, 1989), de-acidification by electrodialysis (Goloubev & Salem, 1989;Vera et al, 2003a;Vera, Dornier, Ruales, Reynes, & Vaillant, 2003b), recovery of natural color substances (Laflamme & Weinand, 1993) and concentration by membrane technologies (Alvarez et al, 2000;Bailey, Barbe, Hogan, Johnson, & Sheng, 2000;Cassano, Jiao, & Drioli, 2004). By complete removal of suspended solids, the efficiency of these post clarification treatments increases considerably.…”

Bitterness reduction in grapefruit juice through active packaging

“…Previous workers have shown that CA in the form of beads, flakes or fibres absorbs limonin from citrus juice. For instance, Johnson and Chandler 11 reported that orange juice was debittered by passage through a CA gel bead column at ambient temperature. The column was able to reduce the limonin content by 55%.…”

“…Experimentally, the bitter component levels can be reduced by the use of column reactors containing immobilized enzymes, [4][5][6][7] immobilized bacteria 8,9 or adsorption on insoluble polymers. [10][11][12][13][14] Naringinase, an enzyme containing a-rhamnosidase (EC 3.2.1.40) and b-glucosidase (EC 3.2.1.21) activity, hydrolyzes naringin to naringenin and prunin; both are non-bitter. This enzyme has been immobilized on several supports and used in column reactors to debitter citrus juice.…”

A Commercial Citrus Debittering System

“…A disadvantage of traditional ion exchange resins is that their chemical activity is too great, which results in a treated juice meeting only one specific regulatory standard (9,40). Hydrophobic adsorbents are limited in their scope based upon their wettability.…”

“…Cyclodextrins have been extensively studied (7,39) but are not currently food use approved. Ion exchange resins and adsorbents, based upon polymers of styreneldivinylbenzene and divinylbenzene, have been studied at great length around the globe (6,8,9,13,34,40). Adoption of these technologies, either to reduce acid with an ion exchange resin or to remove the bitter compounds with an adsorbent, has been found to be economically attractive in many countries.…”