Kansas-based Legacy makes a textured soy protein called TSP, for which it claims to have clients in the human and pet food industries around the world.
It also makes its own brand of soy-bean based products, called Ultra Soy.
It has, in fact, had ties with its new owner for as number of years, as it has sourced soy flour from CHS.
"We've always been impressed with their intense focus and integrity," said Legacy president and CEO Michael Considine.
"As a financially strong, growing company, CHS has the vision and expertise to take this business to the next level."
Company executives were not immediately available to comment on the growth plans of the Legacy business.
But Dennis Wendland, senior VP of CHS's oilseed processing division, under which it will be managed, said in a statement that there are plans to further grow the market for soy protein based products, "to add value for our stakeholders".
Interest in soy protein as an ingredient is piqued not only by the research that is amassing on its nutritional benefits when compared with animal protein, but also by its comparative low cost.
Textured soy protein is used in a broad range of products, including sausages, soups, chilli and fillings, either as a meat replacer or to extend what meat is used in the applications.
A report called Soy-based Food and Drink - US, published by Mintel in October 2007, places current retail sales at $1.4bn, or $1.9bn with Wal-Mart and natural food store sales taken into consideration.
The market researcher said, however, that more awareness efforts need to be made to drive market growth.
Since 2002 Legacy Foods was owned by Simpson Capital, and it has previously been known as PMS Foods.
Financial details of the new acquisition have not been disclosed.
In practical terms, Constantine and his 80-strong staff will continue to work from Hutchinson, Kansas.
For its part CHS is active in the energy, crop nutrients, grain and livestock feed industries - as well as food ingredients.
It processes in excess of 70 million bushels of soybeans every year, and marketing one billion pounds of refined oil.
Owned by farmers, ranchers, cooperatives and stakeholders, it is also active in certain areas of business solutions, and the petroleum/energy market.
Listed on the NASDAQ, CHS reported net income of $750.3m and revenues of $17.2 bn in full year 2007.