Hesperidin in oranges

One of the earliest methods to measure the bitter naringin and other flavanones in grapefruit juice was developed by W. B. Davis in 1947 (12). This test is based on the reaction of dilute alkali with flavanones to form the corresponding yellow chalcones. The flavanone concentration is then determined by measuring the absorbance of the chalcones at 427 nm. Davis pointed out that the procedure was not specific for any flavanone but could be used to determine the principle flavanones in citrus juice, i.e., naringin in grapefruit juice and hesperidin in orange juice. 

Direct ultraviolet spectrophotometric methods have been developed to measure naringin in grapefruit (19J and hesperidin in orange juice (20, 21j. While these methods are rapid, they are also nonspeciTTc for flavonoid bitterness. 

Hendrickson R, Kesterson JW (1964) Hesperidin in florida oranges. Univ Fla Exp Stn Bull 684... 

Figure 2. USDA visual aids used to determine acceptable and unacceptable amounts of hesperidin crystals in orange juice...

An extraction procedure and UV measurement of hesperidin was proposed by de la Torre Boronat et al. (125). They proposed the method as a means of determining the amount of juice in orange based drinks. 

Flavanone glycosides hesperidin and naringin are responsible for the bitterness in oranges and grapefruit, respectively. 

THF/acetonitrile/water (2% acetic acid) gradient [825]. Fluorescent detection gave detection limits of I ppm. During method development, the authors found that resolution was greatest and retention shortest when the organic modifier was THF, followed in terms of decreasing efficiency by acetonitrile and then methanol. These compounds were also baseline resolved from narirutin and hesperidin, two potential HPLC interferent compounds commonly present in orange juice. 

In all the citras fruits, the essential oil is contained in numerous oval, balloon-shaped oil sacs or glands situated irregularly just below the surface of the colored portion of the peel (the flavedo). The white inner mesocarp (the albedo) does not contain any oil sacs but does carry the bitter glycosides such as hesperidin in lemon, orange, and tangerine, or naringin in grapefruit. 

A sweet compound can be obtained from the neutral-tasting hesperidin of oranges by first converting hesperidin to another neutraltasting compound, hesperidin dihydrochalcone. The latter can then be hydrolyzed, by acidic or enzymatic catalysis, to remove the rhamnose residue, yielding hesperidin dihydrochalcone glucoside, which is sweet. The use of dihydrochalcones as sweeteners is discussed in Section 8.8.11. 

Manach, C., Morand, C., Gil-Izquierdo, A., Bouteloup-Demange, C., and Remesy, C., Bioavailability in humans of the flavanones hesperidin and narirutin after the ingestion of two doses of orange juice, Eur. J. Clin. Nutr., 57, 235, 2003. 

For lemon juice, the flavonoid composition was characterized by HPLC with photodiode detection at 287 nm (108), the HPLC condition based on a procedure proposed by Kirksey et al. (103) for the detection of fruit juice adulteration. Hesperidin and eriocitrin were the characteristic flavonoids of lemon juice. Flavonoid content by HPLC was used to study the effects of processing and pulp removal on flavonoid composition in lemon juice. Eriocitrin is also used in distinguishing lemon juice from grapefruit and orange juices, which do not contain this flavonoid. 

JA Manthye, K Grohmann. Concentrations of hesperidin and other orange peel flavanoids in citrus processing byproducts. J Agric Food Chem 44 811-814, 1996. 

Hesperidin Solubility. Hesperidin, a tasteless flavanone glycoside, is the least soluble of all citrus flavonoids. It is found in practically every variety of citrus (5) and is the major flavonoid in sweet oranges and lemons. In fruit or leaves, hesperidin is found as a soluble complex which can be extracted with water or alcohol (5). During juice extraction, the complex is destroyed and hesperTdin slowly precipitates as fine, white, needle-shaped crystals. Once in the solid form, hesperidin can be redissolved in formamide, pyridine or in dilute alkali. 

Hesperidin crystals are found in frost damaged oranges (8) where cells have been disrupted due to the formation of ice crystals. It occasionally precipitates out of concentrated orange juice products during storage and is often found as a... 

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