01964naa a2200241 a 450000100080000000500110000800800410001910000170006024500600007726000090013730000180014649000080016452013690017265000170154165000150155865000120157365000140158565000150159965000130161465300160162770000170164377300620166016441731993-08-17       1983    bl uuuu     u00u1 u    #d1 aHASEGAWA, S.  aSome aspects of citrus biochemistry and juices quality.  c1983  ap.914-918 v.2  vv.2  aStudies on biosynthesis and biodegradation of citrus bitter compounds are reviewed. Substantial progress has been made in the area of limonoid metabolism. Two metabolic pahyways have been firmly established in Citrus and bacteria, and recently a third one has been found in bacteria. Citrus leaves are one site, if not the only site, of limonoid biosynthesis. The leaves appear to be the major source of limonoids present in fruit and seeds. Certain triethylamine derivatives inhibit the accumulation of limonoids in leaves and appear to reduce limonoid content of the fruit to some extent. Limonoid debittering of navel orange juice serum was successfully demonstrated with bacterial cells immobilized in acrylamide gel. The initail steps of the biosynthetic pathway ofthe B-ring of naringin  have been established in grapefruit. Enzymes leading from phenylpyruvate to p-coumarate and also naringin chalcome cyclase have been identified in the fruit. Based on quantitative analyses of naringenin glycosides and the enzymes involved in the pathway during the early stages of fruit development, phenylalanine ammonia-lyase can be singled out as a probable regulatory enzyme in the biosynthesis of flavonoids in grapefruit. Naringinase, particularly in an immobilized form, has a great potential for practical application in reduction of bitterness of citrus juices.  abiosynthesis  abitterness  alimonin  alimonoids  ametabolism  anaringin  aDebittering1 aMAIER, V. P.  tTokyo, Japan: International Society of Citriculture, 1983