Agriculture Reference
In-Depth Information
CH OH
2
CH OH
2
O
CH OH
2
O
O
G
G
G
O
HOH
2
O
O
HOH
2
O
O
HOH
2
O
Fru
Fru
Fru
H
2
H
2
HOH
2
H
2
O
HOH
2
O
O
HOH
2
O
O
O
Fru
Fru
Fru
CH OH
2
CH
2
CH
2
1-Kestose
HOH
2
O
HOH
2
O
O
O
Fru
Fru
CH OH
2
CH
2
Nystose
HOH
2
O
O
Fru
CH OH
2
Fructosylnystose
Figure 4.3.
Chemical structures of fructooligosaccharides with one, two, and three fructose molecules.
Phytosterols
Phytosterols or plant sterols are found in all food items
of
C
2
plant
origin.
The
most
common
plant
sterols
are
H
2
β
-sitosterol, campesterol, and stigmasterol classified as
4-desmethylsterols of the cholestane series (Kochar, 1983).
Their structures are similar to that of cholesterol with an ex-
tra methyl or ethyl group and a double bond in the side chain
(Fig. 4.4). Saturated plant sterols, referred to as stanols,
have no double bond in the ring structure (Heinemann et al.,
1991). Plant sterols can exist as free plant sterols, esteri-
fied plant sterols, plant steryl glycosides, and acylated plant
steryl glycosides (Nes, 1987).
OH
(A)
Occurrence
The phytosterol content and composition in the fruits
may be influenced by the genetic makeup of the fruits,
stage of maturity, agronomic practices, geographic loca-
tion, and storage conditions after harvest. The total phy-
tosterol content of some tropical and subtropical fruits and
(B)
Figure 4.4.
Chemical structure of (A) phytosterol
and (B) cholesterol.
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