Starches are the major storage polysaccharides in foods of plant origin. Worldwide dry starch production is actually estimated at more than 64 million tons and almost 75 million tons are expected by 2012 (Patil, 2009). Current annual production for primary starch sources is estimated to be 46.1 million tons of corn, 9.1 million tons of cassava, 5.15 million tons of wheat, and 2.45 million tons of potato (Röper and Elvers, 2008).
Starches from cereals come mainly from corn and wheat. European countries are responsible for around 60% and Asia produces 20% of the global production of wheat starch used in dextrin and modified starches. The United States is still the largest producer of corn starch in the world (LMC, 2008). In Western Europe, 46% of produced starch is from corn, 36% from wheat, and 19% from potato starches (Röper and Elvers, 2008), whereas North American production of starch is based almost entirely on corn (LMC, 2008). Actually, the Asian corn starch sector, particularly in China, is growing consistently at over 15% per year, competing with United States and European producers (LMC, 2008).
Because of their lower moisture content, cereals have longer storage times and their starch extraction is easier and faster than in roots and tubers. For example, in cassava, high water consumption is a critical factor in the starch extraction process. In this process, water is used during the grinding, decantation, and washing steps and these large quantities of water are converted to wastewater, which must be treated before being released to the environment. Liquid waste has a high biochemical and chemical oxygen demand; its treatment comprises several steps and requires a long retention time. After extraction and separation, starch moisture content is from 35 to 40%, requiring a great deal of energy in the drying process (Sriroth et al., 2000).
Although cassava production is growing and starch from cassava competes with the corn processors (Patil, 2009), corn still remains the main starch source in the world, followed by cassava, potato, and wheat. More than 70% of starch produced in the world is from corn (Röper and Elvers, 2008). However, starch from roots and tubers shows some particular rheological and physical properties, such as clear gel, high viscosity, and lower retrogradation, which are required in the formulation of specific products. Demand for cassava starch has grown in the past few years and it is actually the most widely traded form of native starch in the world, mainly in Vietnam, Thailand and East Asia. Asia contributes around 90% of cassava starch produced for use in industry (LMC, 2008), with Vietnam and Thailand being the major producing country, followed by China and Indonesia (FAO, 2008). In 2006, around 3.5 × 106 tons of cassava starch were produced in Thailand. Of this amount, 2.3 × 106 tons were exported, with 1.67 × 106 tons as native starch and 638 × 103 tons as modified starches (Röper and Elvers, 2008). In South America, which is responsible for the other 10% of cassava starch production, Brazil is the main producer (FAO, 2008).
Considering starches from roots and tubers, potato starch is the second largest starch source. In Europe, strong support of the grain sector has resulted in decreasing production of potato starch (LMC, 2008). However, European countries are still responsible for 80% of potato starch production in the world (LMC, 2008), with the Netherlands, France, Belgium, Germany, and Switzerland as the main potato producers (FAO, 2008).