Bitterness reduction of naringin and limonin by .BETA.-cyclodextrin.

Taste interactionsof /?-cyclodextrin with naringin or limonin, which are bitter tasting constituents of citrus fruits and their products, were evaluated by psychophysical methods.The mechanism of interaction of /?-cyclodextrin with naringin or limonin was explained by both the solubilities of the bitter tasting compoundsand the changes brought about by proton shifts within the jS-cyclodextrin.In the presence of 0.5% j5-cyclodextrin, the bitterness of naringin or limonin was reduced to approximately half of what it was without jS-cyclodextrin.This reduction in bitterness by /?cyclodextrin was also observed in the citrus juice itself.The solubilities of naringin or limonin increased with the addition of /?-cyclodextrin.In a series of XHNMRspectra of j5-cyclodextrin in D2O, the low-field triplet signals assigned to the H-3 and H-5 protons, which are located within the cavity of /?-cyclodextrin, showed a gradual shift to the higher-field values with increases in the molar ratio of naringin to jS-cyclodextrin.It was concluded that this bitterness reduction was due to the formation of an inclusion complex between the /?cyclodextrin and the naringin or limonin.The bitterness of citrus fruits and their products is caused primarily by either of two constituents-naringin and limonin.Naringin is said to be the bitter tasting constituent of grapefruit, natsudaidai, buntan oranges and so forth.1}On the other hand, limonin is the bitter tasting component of navel oranges, Valencia oranges and iyo oranges, among others.2'3)These bitter compounds are often necessary