The application of natural hydrocolloids to foods and beverages - Natural Food Additives, Ingredients and Flavourings - page 183

LMA pectin is more reactive to calcium, so can make use of natural calcium
present, for example, in dairy products. An advantage is that it is less sensitive to
variations in calcium levels. LMA pectin gels normally have a more spreadable
texture than LM pectin gels, are not bake stable (gels remelt), are less prone to
syneresis and have better freeze-thaw stability.
The traditional applications for HM pectin are jams, jellies and marmalades,
and confectionery jellies. For low-sugar versions, LM or LMA pectin will be
required. HM and LM pectins are used for bakery jellies, which are applied to
baked goods before baking, so must be pumpable and resist melting.
Pectins have two distinct functions in dairy products. HM pectin can act as a
protein dispersion stabiliser in acid dairy systems such as yoghurt drinks, fruit
juice/dairy drinks, and acidifi ed soya drinks by a charge interaction with the
casein protein, preventing it from precipitating at its isoelectric point. LM pectins
can be used to gel neutral milk desserts or add texture to yoghurts by interaction
with the calcium and milk proteins. LM pectins are also used to prepare the fruit
preparations used in yoghurts, ensuring good stability and even fruit dispersion
while in bulk storage and during pumping into the fi nal product.
With the interest in using pectin as a natural hydrocolloid in a wider range of
food products to replace less popular hydrocolloids, pectin is being used in sauces,
especially oriental sauces for ready meals, and acid table sauces. This tends to be
in the premium ranges only due to the higher cost of pectin compared with
traditional thickeners such as starch.
One newer application is the stabilisation of fl avour emulsions. This is a
different type of pectin, produced from sugar beet, which has completely different
functionality, used primarily for its emulsifying properties, and can be used to
replace gum arabic.

8.3.4 Konjac
Konjac gum is derived from the tuber (root) of the Amorphphallus konjac plant,
also known as the Elephant yam. This natural ingredient has been used in Asia for
centuries in traditional food such as noodles. Tubers are harvested after two to
three years, when they contain 30-50% glucomannan, making it economical for
commercial extraction. After harvesting, the tubers are washed and then sliced
into chips to assist in drying. After drying, the dried tubers are ground and
separated by air classifi cation. The heavier idioblast sacs, which contain the
konjac gum, are recovered and washed with alcohol and water to remove the
starch, protein and other unwanted materials. Finally the powder is dried, ground
and blended.
Konjac is a high molecular weight, non-ionic, linear glucomannan consisting
of D -mannose and D -glucose units in the ratio 1.6:1. The β -1,4-linkages in the
glucomannan chain resist enzymic degradation during digestion; hence konjac
gum is a source of soluble fi bre. The glucomannan chain has short side branches
and acetyl groups randomly present (approximately every 9-19 residues). These
affect the gelling properties of the gum, and deacetylation using a weak alkali and

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