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United States Department of Agriculture

Agricultural Research Service


High-Protein Bean May Improve Soy Infant Formula

By Jill Lee
December 30, 1998

RALEIGH, N.C., Dec. 30--Prolina, a high-protein soybean from the U.S. Department of Agriculture’s Agricultural Research Service, appears to have the right amino acid mix to make soy infant formula more like mothers’ milk.

Among Prolina's appealing qualities is an unusually high concentration of cystine, an amino acid that occurs naturally in human breast milk. Some scientists think cystine might be important for brain and eye development.

“Prolina, a soybean bred for animal feed, turns out to have potential for improving soy infant formulas," said ARS Administrator Floyd P. Horn. "This is another example of how research aimed at helping farmers can have spinoffs leading to new value-added products and to improved nutrition for people."

ARS plant geneticist Joseph Burton bred Prolina at the agency's Soybean and Nitrogen Fixation Laboratory in Raleigh, N.C.

ARS chemist Prachuab Kwanyuen, a colleague of Burton’s, said, “Prolina soybeans are high in 11S and 7S proteins, a special class of proteins with enhanced functional properties. This means it’s easier to process these beans into a gel form for a fat-free whipped cream made from soy--or to blend them into a liquid emulsion like infant formula.”

Kwanyuen has been working with food scientists at North Carolina State University to develop new products, such as high-protein soyburgers, based on Prolina’s properties.

While Prolina's potential for innovative food products is valuable, "it's the high concentration of the amino acid cystine that makes Prolina a good candidate for an infant formula base," Kwanyuen said. Prolina has several times more cystine than regular soybean varieties, he added.

Cystine is a key part of human breast milk. In fact, humans have a higher ratio of cystine in their breast milk than all other mammals. Scientists have speculated that high cystine levels promote brain and eye development because the body uses it to make taurine, a compound highly concentrated in these organs.

"Many formula manufacturers have been looking for a way to more closely match mother’s milk with a vegetable-based formula," Kwanyuen said. "Prolina may just be the formula for success."

Breast feeding is preferable to formula for all infants, but sometimes this isn’t possible, particularly if the infant has trouble digesting larger proteins found in breast milk. Soy formula can be an alternative.

Scientific contact: Prachuab Kwanyuen, Soybean and Nitrogen Fixation Laboratory, Raleigh, N.C., phone (919) 515-2734, fax (919) 515-7959,

Last Modified: 5/15/2017
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