Food Chemistry

4.4 Polysaccharides 325

Table 4.26.Utilization of amylopectin and its deriva-
tives

Starch Utilization

Unmodified waxy starch Salad dressing, sterilized

(also in blend with canned and frozen food,

normal starch and soups, broth, puffed cereals,

flours) and snack food

Pregelatinized waxy Baked products, paste

starch or isolated (pâté) fillings, sterilized

amylopectin bread, salad dressing,

pudding mixtures

Thin boiling waxy starch Protective food coatings

Cross-linked waxy Paste fillings, white and

starch brown sauces, broth,

sterilized or frozen canned

fruit, puddings, salad

dressing, soups, spreadable

cream products for sand-

wiches, infant food

Waxy starch, Sterilized and frozen

hydroxypropyl ether canned food

Waxy starch, Emulsion stabilizer

carboxymethyl ether

Waxy starch acetic Sterilized and frozen canned

acid ester food, infant food

Waxy starch succinic- Sterilized and frozen canned

and adipic acid esters food, aroma encapsulation

Waxy starch sulfuric Thickenig agent, emulsion

acid ester stabilizer, ulcer treatment

(pepsin inhibitor)

and as an adhesive or binding agent. Table 4.26
lists the range of its applications.

4.4.4.14.6 ResistantStarch.........................................

Starch and its degradation products which are not
absorbed in the small intestine are called resistant
starch (RS). RS can, however, be metabolized by
the bacteria of the colon. Acetic acid, propionic
acid and butyric acid are formed, stimulating the
growth of the cells of the intestinal epithelium.
Especially butyric acid has been found to posi-
tively affect health. A distinction is made between
4 forms of RS: Type I, starch enclosed in cells
(e. g., coarse-ground grain or legumes), Type II,
native starch granules (e. g., in bananas, potatoes),
Type III, starch fractions produced on retrograda-
tion (e. g., in boiled potatoes, bread crumb), and

Type IV, starch modified by theMaillardreaction

or caramelization (formation of glycosidic bonds

which are not hydrolyzed byα-amylase).

Only amylose, and not amylopectin, is involved

in Type III RS. The formation of RS depends on

the temperature and on the water and lipid con-

tent. Indeed, 20% of RS is obtained on autoclav-

ing corn starch. The yield can be raised to about

40% by heating under pressure and cooling (ca.

20 cycles). The optimal amylose/water ratio is

1:3.5 (g/g). Lipids complexed by amylose inhibit

RS formation (cf. 15.2.4.1).

Type III RS consists of 60–70% of double he-

licalα(1–4)polyglucan aggregates and only 25–

30% of crystalline structures. It is assumed that

the high content of the double helical conforma-

tion, which is similar to that of amylose type B,

limits the activity ofα-amylases.

Various methods have been proposed for the

determination of RS, e. g., RS equals total starch

minus digestible starch. The results are only

comparable if the incubation conditions and the

α-amylases used correspond.

4.4.4.15 ModifiedStarches.......................................

Starch properties and those of amylose and amy-

lopectin can be improved or “tailored” by physi-

cal and chemical methods to fit or adjust the prop-

erties to a particular application or food product.

4.4.4.15.1 MechanicallyDamagedStarches

When starch granules are damaged by grinding or

by application of pressure at various water con-

tents, the amorphous portion is increased, result-

ing in improved dispersibility and swellability in

cold water, a decrease in the gelatinization tem-

perature by 5–10◦C, and an increase in enzy-

matic vulnerability. In bread dough made from

flour containing damaged starch, for instance, the

uptake of water is faster and higher and amylose

degradation greater.

4.4.4.15.2 ExtrudedStarches.......................................

The X-ray diffraction diagram changes on extru-

sion of starch. The V-type appears first, followed