Naringine, removal

Different extracts of Citrus were subjected to SPE on Cig cartridges to remove polar components. The retained flavonoids (mainly flavanones) were eluted with methanol-dimethyl sulfoxide, which enhanced solubility of hesperidin, diosmin, and diosmetin. Recoveries of eriocitrin, naringin, hesperidin, and tangeretin from spiked samples of mesocarp tissue exceeded 96%. Flavones were relatively abundant in the leaves. ... 

Fruit juices can be deacidified with a weak base anion-exchange resin. Removal of compounds which cause a bitter taste is a more popular application (26,27). It is accomplished with resins that have no ion-exchange fimctionality. In essence, they are similar to the copolymer intermediates used by resin manufacturers in the production of macroporous cation and anion exchangers. These products are called polymeric adsorbents. They are excellent for removal of limonin [1180-71-8] and naringin [1023647-2], the principal compounds responsible for bitterness in orange, lemon, and grapefruit juices. The adsorbents are regenerated with steam or alcohol. Decaffeination of coffee (qv) and tea (qv) is practiced with the same polymeric adsorbents (28). 

Control of Juice Bitterness. A number of advances have been reported in this field since it was last reviewed (3). A commercial application of the cellulose acetate adsorption technique for the removal of limonin from citrus juices was undertaken (49). New sorbent gel forms of cellulose esters for adsorption of limonin were developed (50). Knowledge was gained that limonoids are biosynthesized in citrus leaves and translocated to the fruit (12) and that specific bioregulators can inhibit accumulation of XIV in citrus leaves (15). Additional studies were carried out on the use of neodiosmin to suppress limonin and other types of bitterness (30,51). The influence of extractor and finisher pressures on the level of limonin and naringin in grapefruit juice was reported (34). Also, further studies were conducted on the microbial sources and properties of limonoate dehydrogenase (52), the enzyme that converts XIV to XV and can be used to prevent limonin from forming in freshly expressed citrus juices (53). 

Investigations on possible commercial use of enzymes to remove naringin bitterness were carried out for juice (70, 71), concentrate (71), and fruit sections (72). Those investigations showed that it was technically possTFle to use enzymes to reduce naringin bitterness on a commercial scale. However, due to enzyme expense, most of the industry has found it more cost effective to use more mature (less bitter) fruit rather than employ debittering enzymes. 

Bitterness, caused by naringin, is also removed by an enzyme, naringinase. Another possibility would be to eliminate one or more of the enzymes in the limonin biosynthetic pathway by using recombinant DNA techniques. Limonin, a triterpenoid, is probably synthesized via the mevalonate pathway, as are the monoterpenoid flavor compounds. It appears that nomilin, a precursor of limonin, is synthesized in the stems and roots of citrus and then the precursor transported to the fruit where it is converted by several enzymes to limonin and other bitter limonoids (46). 

Removal of polyphenolic compounds Recovery of starch from wheat flour Debittering citrus pectin juice by hydrolysis of the glucoside, naringin... 

Bitter taste remover. Based on an immobilised enzyme, naringinase, in a cellulose acetate film to remove the bitter taste (naringin and limonin ) from grapefmit juice. 

Most of the bitter glucosides are in the albedo and segment membranes so that commercial production of grapefruit juice without removal of naringin is possible. Production of juice from natsudaidai oranges 180) and restoration of the pink color to pink grapefruit juice by addition of pulp 181) require debittering. 

Physical Removal During the past several years, significant progress has been made in the development of selective adsorption processes for removal of two bitter principles, limonin and naringin, from citrus juices. Adsorbents such as cellulose esters (43), cross-linked polystyrenes (44) and 6-cyclodextrins (45, 46) have been shown to reduce effectively the limonin bitterness in the juice. 

Polystyrene-divinylbenzene cross-linked copolymer adsorbent resins removed effectively both limonin and naringin from citrus juices (44). Over 85% of limonin was adsorbed from about 50 bed volume juices of grapefruit, navel orange, lemon and tangerine. Up to 70% of naringin was also removed from grapefruit juice. 

Removal of limonene and naringin (P-cyclodextrin) CSTR with UF membrane Production of bitterness and claiification of fruit juice... 

CyD applications are by no means restricted to the pharmaceutical industry. Several examples, mainly prospective ones, are scattered throughout this book. CyDs are used to remove unpleasant tastes, odors, or other undesirable components in the food industry, in agrochemistry, cosmetics, dying, cleaning, and in many other areas. To name just a few examples of numerous CyDs applications grapefruit juice loses its unpleasant taste when its bitter component naringine is removed by complexation with yS-CyD [61] similarly, removal of phenylalanine and tyrosine... 

Flavonoid glycosides provide an excellent fingerprint for juices that are not subjected to extensive pretreatment to remove them. There are a large number of these compounds in citrus juice. Hesperidin and narirutin are typical of sweet orange, whereas naringin and neohesperidin can be used to... 

Naringase Naringin Naringenin + carbohydrate Removal of the bitter taste of grapefruit juice. Naringenin is less bitter than naringin. 

---