114A-16 |
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F. O. URUAKPA and S. D. Arntfield. Dept. of Food Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada Biopolymer mixtures contribute to the formation of gel networks in food systems. Effective utilization of these networks depends on the understanding of the type and role of interactions involved in network formation. There is no published information on how molecular interactions are related to the structural arrangement of mixed gels that contain commercial canola protein. This study examined the structural ordering of canola protein isolate-k-carrageenan gels and the molecular forces that stabilize and strengthen network structure. The microstructure of canola protein isolate (CPI), k-carrageenan (k-CAR) and CPI-k-CAR gels were assessed using scanning electron microscopy (SEM). Visual observations and SEM documentations were made, and SEM images of each gel were obtained. The effects of pH, urea and dithiothreitol (DTT) on the network structure of CPI and CPI-k-CAR gels were evaluated. Individual CPI gels showed varied structures at acidic and alkaline pH. At pH 6, loosely-crosslinked protein networks with empty cells/holes that entrapped liquid components were observed, whereas properly-crosslinked network structures were obtained at pH 10. Network structures of individual CPI and k-CAR gels were greatly improved when the two macromolecules were combined, indicating a synergistic behavior between CPI and k-CAR. Urea and DTT affected the interactions involved in network formation as well as the structural arrangement of CPI-k-CAR gels. Gels treated with urea were excessively crosslinked, showing a marked alteration of the gel structure; whereas systems treated with DTT had an amorphous structure. Results support the involvement of disulfide bonds and noncovalent interactions in the structural arrangement and strengthening of canola protein-k-carrageenan gels. A better understanding of the factors responsible for enhancing the physical and textural properties of CPI in food systems will provide a basis for value added processing of canola meal, which is currently sold as an animal feed ingredient.
Session 114A, Food Chemistry: Colloidal systems and enzyme chemistry
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