59D-25 |
Functional properties of whey from a mixture of cow's milk and soybean drink at pH 4.5 |
A. K. OBUBUAFO, T. M. S. Antunes, H. Mongi, C. Munene, Z. Xu, J. S. Godber, and J. N. Losso. Department of Food Science, Louisiana State University Agricultural Center, Baton Rouge, LA 70803 Soybean whey obtained after acidification and precipitation of major soybean proteins in aqueous soybean extract at pH 4.5, contains health enhancing bioactive compounds such as isoflavones, the Bowman-Birk inhibitor, saponins, phytic acid, and oligosaccharides. Recently, consumption of dressings and sauces has increased significantly as more people eat salads to maintain good health. In general, poor functionality of whey protein at acidic pH necessitates its use in combination with other emulsifiers in dressings and sauces. In an effort to provide food ingredients with added functional and health benefits, we hypothesized that a mixture of cow's milk and soy drink, compared to milk whey, can provide a whey mixture with improved functionality for salad dressings. The objective of this research was to compare the functional properties of milk whey (BW) and whey from a mixture of cow's milk and soybean drink (BBW) at pH 4.5. A mixture of skim milk and soybean drink (1:1 ratio) was adjusted to pH 4.5 with HCl and the filtered supernatant was lyophilized. Protein, isoflavones, oligosaccharides, saponins, and the Bowman-Birk inhibitor (BBI) were analyzed. Foaming and gelling properties were determined. Oil-in water emulsions containing 1 or 3% protein, prepared by homogenization in an APV-homogenizer at 3000 psi were tested for emulsion stability. BBW contained the anticarcinogen BBI and an average of 1.1 mg of isoflavones per g of sample (24% protein). BW stabilized emulsions collapsed within 24 h while BBW stabilized emulsions were stable for more than 5 d at 21°C. High oligosaccharide content of BBW caused an increase in its gelation temperature compared to BW. Saponins and proteins cooperatively improved BBW emulsion stability. The greatest foaming capacity and foam stability resulted from BBW. BBW will add functional and health benefits of soybean bioactive compounds and reduce the amount of stabilizers in dressings and sauces.
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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