Food Chemistry

18.1 Fruits 833

Table 18.23.Flavanones and flavones in citrus fruitsa

Polyphenol glucosideb Orange, sweetc 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.

aValues in mg/kg fresh weight; n.d., not detected.
bApi: apigenin, Dio: diosmetin, Eri: eriodictyol, Hes: hesperitin, Isa: isosakuranetin, Nar: naringenin, Que: quer-

cetin, rut: rutinose (O-α-L-Rhap-(1→6)-D-Glcp), neo: neophesperidose (O-α-L-Rhap(1→2)-D-Glcp)
cC. sinensiscv. Valencia
dC. sinensisvar Brasiliensis cv. Morita contained 14 mg/kg naringin

Table 18.24.Taste of flavanone glycosidesa

Compound R R^1 R^2 Taste

quality intensityb

Naringenin-
rutinoside rutc H OH neutral –
Naringin neod H OH bitter 20
Isosacura-
netin-ruti-
noside 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

aData for R, R (^1) and R (^2) refer to Formula 18.28.
bRelative bitterness refers to quinine hydrochloride =
100.
cRutinosyl.
dNeohesperidosyl.
kali fragmentation to a methylketone (IV), con-
densation with isovanillin (V) to the correspond-
ing 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 enzy-
matic 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.