July 7/Beijing/Food Business Week -- According to a study from Beijing, China, "Three soy protein isolates (SPIs) were obtained by different drying methods, including freeze-drying, spray-drying and vacuum-drying. These SPIs were found to be significantly different in color of CIELAB L*, a*, b* values, enthalpies of denaturation (Delta H) in differential scanning calorimetry, 1-anilino-8-napthalene-sulfonate surface hydrophobicities and total sulfhydryl group contents (P<0.05)."

"The solubility of spray-dried SPI was significantly higher than that of freeze-dried SPI and vacuum-dried SPI (P<0.05), except at pH 4-5. Spray-dried SPI had much lower turbidity, higher solubility and better emulsifying and foaming properties than freeze-dried and vacuum-dried SPIs," wrote X.Z. Hu and colleagues, China Agricultural University.

The researchers concluded, "These results suggested that drying methods could influence the functional properties of SPIs."

Hu and colleagues published the results of their research in the Journal of Food Processing and Preservation ("Effects Of Drying Method On Physicochemical And Functional Properties Of Soy Protein Isolates." Journal of Food Processing and Preservation, 2010;34(3):520-540).

For additional information, contact L.T. Li, China Agricultural University, College Food Science & Nutrition Engineering, 17 Qinghua Dong Rd., Beijing 100083, People's Republic of China.

From the July 19, 2010, Prepared Foods E-dition