Starch, and functional properties. Innumerable starch sources, modifications and

Starch, a polymer of glucose joined by glycosidic bonds, is the
most abundant biopolymer next to cellulose and chitin. Structurally, it
comprises ?-D-glucopyranosyl residues straight linked in amylose and branched
in amylopectin. Starch is obtained from plants, mostly cereals (e.g., rice,
maize and wheat) and roots (e.g., potato, cassava and taro). It is extracted by
using appropriate solvent systems as the source plants contain blends of
various materials 1, 2. Physicochemical properties of starches
such as morphology, granule size, crystallinity, moisture-uptake, swelling,
gelatinization and viscosity vary with botanical source even from variety to
variety 3-5. The native starch granules can be small (2-40 ?m) or
large (50-150 ?m). Though amylose to amylopectin is the core structural factor
for starch applications, its granules contain proteins and lipids. Composition
of granules, molecular length and branching density of starches
make the basis for the rest of its physicochemical
and functional properties. Innumerable starch sources, modifications and
derivatives provide vital inputs for pharmaceutical, food, paper and textile
manufacturing inter alia for starch
is renewable, biodegradable, low cost polymer and most abundant biopolymer next
to cellulose 6. It is widely
available, ecofriendly, modifiable and biocompatible by virtue of design by ­nature
2.

Taro (Colocasia esculenta)
is a tropical and subtropical herbaceous monocotyledonous, perennial stem root
crop with large heart shaped leaves. Taro Boloso-I (Fig. 1) is an improved new
variety of C. esculenta officially
released from Areka Agricultural Research Center.
The marketable yield of Taro Boloso-I outweighs the other cultivar by average
of 67% 7 that is why its vernacular name in Wolaittgna is
“Barakata” meaning “Blessed”.  Raw Taro Boloso-I
contains 85.65 ± 0.07% of carbohydrate on dry basis. It has gross energy
content comparable to that of maize, higher than that of cassava, Irish potato, yam, sweet potato and other
taro cultivars8.

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Starch, as a natural polymer, is preferable to semi-synthetic and
synthetic ones. In line with advances in biotechnology, its applications,
modifications and derivatizations and demands are scaling up. Thus, any notable
progress, even slight, of a starch will bring about great societal impact with
such an immense utilization 6. There is no significant body of
knowledge regarding the distinctive physicochemical properties of starch from
Taro Boloso-I. Thus, isolation and physicochemical characterization including
proximate composition, amylose to amylopectin ratio, bulk powder properties,
crystallinity, hydrothermal property and properties in water were investigated
in the present work.