Chemical and Functional Properties of Food Saccharides

© 2004 by CRC Press LLC
8.4.3.6 Protein Recovery — By-Products
8.5 Cassava (Tapioca, Manioc) Starch
8.5.1 General Remarks
8.5.2 Processes
8.5.2.1 Chopping and Rasping
8.5.2.2 Starch Extraction and Purification
8.5.2.3 Starch Dewatering and Drying
References
8.1 PRODUCTION AND MARKETS
8.1.1 GLOBALLY USED SUBSTRATES
Starch is deposited in different storage organs of numerous plants in the green
environment and functions as an essential energy reservoir. Thus, starch, together
with other storage compounds, enables plants to start a new cycle in plant reproduction.
Several cereal grains as well as some tubers and roots are cultivated for
being utilized as substrates for starch production.
Maize (corn) is the major source of starch worldwide, even in many countries
that use rather small quantities in production and are therefore frequently indicated
in the category “other countries.” Over 80% of the starch produced globally is
extracted from maize, generally named corn in the U.S. Wheat comes second as raw
material because the European Union (E.U.) relies greatly on this crop. However,
not more than ca. 8% of global starch production is derived from wheat. Potato takes
the third position, and again the E.U. dominates the production of this starch type
by historical tradition. The group of the most important plants used as raw materials
for starch production is completed with a tropical root known by different botanical
synonyms, such as cassava, tapioca, or manioc. The production of starch from this
root contributes to over 5% of the world’s production and is concentrated in Southeast
Asia and South America. In addition to these substrates, only a few other plants are
raw materials, although numerous others have promising property profiles. Rice,
barley, oats, sweet potatoes, and sago trunks are locally used in substantial quantities.
The domination of maize can be easily explained by the cost competitiveness
in regional markets and the scale and value of by-products that contribute to cost
calculation. Here again, maize and wheat offer several advantages, with valuable
products such as vegetable oil provided by maize germs or vital gluten recovered
from wheat. In contrast, with potatoes and cassava as starch plants, there is no
significant additional profit because commercialization of by-products, proteins, and
fibers covers only expenses. In the potato protein, however, a generally low sensorial
quality allows it to be used as feed only, but it can eventually be transformed into
a food-grade product by additional but costly purification measures.
8.1.2 WORLD STARCH PRODUCTION
A recently published E.U. study estimated the world starch market at 48.5 mt (million
tonnes) in 2000. 1 This figure includes the total amount of starch used for production