July 21/Foggia, Italy/Food & Farm Week -- According to recent research from Foggia, Italy, "Spaghetti produced in a pilot plant were made from semolina and semolina blended with 10%, 15%, 25% or 50% of defatted soy flour (DSF) or toasted soy flour (TSF). Proteins of spaghetti were characterized by size exclusion-high-performance liquid chromatography (SE-HPLC)."

"Soy globulins interact with semolina proteins during pasta making, forming polymers of high molecular weight. Of these, the sodium dodecyl sulphate-unextractable components were significantly higher (p<0.001) (up to 49% unextractable polymeric proteins) (UPP) than that of spaghetti made of semolina (24.6% UPP). The decrease of S-S bonds and the increase of -SH free groups in the DSF-semolina spaghetti, with respect to that made of only semolina, suggest that polymerization among the different classes of proteins involves interaction by sulphydryl residues in blends with above 15% of DSF and that soy proteins tend to disrupt own gluten S-S interchange system," wrote C. Lamacchia and colleagues, University of Foggia.

The researchers concluded, "In the TSF-semolina spaghetti, the increase of S-S bonds was higher with respect to that of -SH free, suggesting that the heat treatment, to which the TSF proteins were subjected, allowed them to cross link to semolina proteins by disulphide bonds."

Lamacchia and colleagues published their study in Food Research International ("Study on the Interactions Between Soy and Semolina Proteins During Pasta Making." Food Research International, 2010;43(4):1049-1056).

For additional information, contact C. Lamacchia, University of Foggia, Dipartimento Science Alimenti, Via Napoli 25, I-71100 Foggia, Italy.

From the August 2, 2010, Prepared Foods E-dition