Cassava shapes up as an alternative source for starch sweeteners
Cassava, also known as tapioca, is cultivated across large areas of Africa and Asia, and global production is continuing to increase. Estimated to be 260 million tonnes in 2012, production had been projected to reach 275 million tonnes by 2020. In fact, the authors of this paper predicted that, thanks largely to higher yields per hectare, global production could reach 300 million tonnes by that date.
Enzymes are already used to produce sweeteners from cassava starch. “It is already an established industry in countries such as Thailand and Indonesia,” said Jay Shetty at Du Pont California, lead author of the paper. “It is now growing in China and other southeast Asian and African countries.”
But he added: “It is not everywhere where it should be, and it is our job to bring that to people’s attention. It would also require further development.”
Cassava root is up to 30% starch. Yields could improve further if more of an effort was made to extract starch from the stems as well, whether for use as a food in its own right, a source of ingredients or feedstock for ethanol production, said the authors.
According to DuPont, the higher starch and lower protein and fat content compared with other sources means that cassava root has distinct advantages as a starting feedstock for the production of maltodextrins, maltose and glucose syrups and the high-glucose feed used to produce high-fructose syrup. But it also means that the enzyme-driven processes used with maize and wheat may need to be adapted in order to optimise results with cassava.
A process of enzymatic hydrolysis takes the feedstock through a two-stage liquefaction, followed by purification and an isomerisation process to yield high-fructose syrup.
“This is not proprietary technology,” said Shetty. “We simply applied our knowledge of corn to cassava. DuPont has taken the lead in helping our potential customers.”
Although publisher of the paper Mary Ann Liebert Inc speculated about cassava “replacing corn as the main source for starch sweeteners”, the authors’ claims appear to be more modest.
“We have made a suggestion about the use of cassava in those countries where it is grown, and where they do not grow cane sugar and corn,” said Shetty. “They do not have to import it, and it will support the rural economy.”
The point about supporting, rather than undermining, local economies is an important one. “It will not pose a problem to local food supply. This will create significant value to customers.”
He added that process implementation and training would, “take some time”.
Source: Industrial Biotechnology
Published online ahead of print, doi: 10.1089/ind.2014.0010
“Cassava, the Next Corn for Starch Sweeteners”
Authors: Jay K. Shetty, Bruce A. Strohm, Sung Ho Lee, Gang Duan and David Bates
