2009_Book_FoodChemistry

18.1 Fruits 833
Table 18.23. Flavanones and flavones in citrus fruits a
Polyphenol glucoside b Orange, sweet c Bitter orange Grapefruit Lemon
Fruit Peel Fruit Peel Fruit Peel Fruit Peel
Flavanones
Eriocitrin (Eri-7-rut) 159 59 49 38 183 92 1020 1320
Neoeriocitrin (Eri-7-neo) 27 n.d. 2100 2200 n.d. n.d. n.d. n.d.
Narirutin (Nar-7-rut) 1660 665 170 220 1700 1900 114 225
Naringin (Nar-7-neo) n.d. d n.d. 9790 14,700 13,600 21,000 n.d. n.d.
Hesperidin (Hes-7-rut) 9620 14,100 n.d. n.d. n.d. n.d. 3560 711
Neohesperidin (Hes-7-neo) n.d. n.d. 6840 10,900 210 203 n.d. n.d.
Neoponcirin (Isa-7-rut) 571 421 16 27 53 84 n.d. n.d.
Poncirin (Isa-7-neo) n.d. n.d. 2820 5670 3040 462 n.d. n.d.
Flavones
Rutin (Que-3-rut) 108 n.d. 290 473 51 51 n.d. n.d.
Isorhoifolin (Api-7-rut) 3 11 20 37 n.d. n.d. 158 355
Rhoifolin (Api-7-neo) 15 58 566 1080 95 184 13 29
Diosmin (Dio-7-rut) 14 55 16 38 n.d. n.d. 208 432
Neodiosmin (Dio-7-neo) 77 30 173 438 185 110 n.d. n.d.
a Values in mg/kg fresh weight; n.d., not detected.
b Api: apigenin, Dio: diosmetin, Eri: eriodictyol, Hes: hesperitin, Isa: isosakuranetin, Nar: naringenin, Que: quercetin,
rut: rutinose (O-α-L-Rha p -(1 → 6)-D-Glc p ), neo: neophesperidose (O-α-L-Rha p (1 → 2)-D-Glc p )
c C. sinensis cv. Valencia
d C. sinensis var Brasiliensis cv. Morita contained 14 mg/kg naringin
Table 18.24. Taste of flavanone glycosides a
Compound R R 1 R 2 Taste
quality intensity b
Naringeninrutinoside
rut c H OH neutral –
Naringin neo d H OH bitter 20
Isosacuranetin-rutinoside
rut H OCH 3 neutral –
Poncirin neo H OCH 3 bitter 20
Hesperidin rut OH OCH 3 neutral –
Neohesperidin neo OH OCH 3 bitter 2
Eriocitrin rut OH OH neutral –
Neoeriocitrin neo OH OH bitter 2
a Data for R, R 1 and R 2 refer to Formula 18.28.
b Relative bitterness refers to quinine hydrochloride =
100.
c Rutinosyl.
d Neohesperidosyl.
kali fragmentation to a methylketone (IV), condensation
with isovanillin (V) to the corresponding
chalcone (VI), then hydrogenation:
(18.30)
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.