59D-4 |
Texture and protein-Protein interactions of heat-formed fish myofibrills/egg white gels |
A. MORA-GUTIERREZ, H. Cromwell, and E. Risch. Cooperative Agricultural Research Center, Prairie View A&M University, PO Box 4079, Prairie View, TX 77446 Heat-induced gelation of surimi is of primary importance in manufacturing a variety of surimi seafoods. The ability of egg white (EW) to form gels upon heating is a major factor in its utilization as ingredient during surimi processing. The textural data can be useful in assessing the degree to which EW proteins cooperate in the gelation process to affect the gel strength (hardness) of surimi seafoods. Low molecular weight carbohydrates (e.g., sucrose, sorbitol) are widely used as cryoprotectants and induce gelation in fish mince proteins (surimi). Textural properties of fish myofibrillar (MF) protein gels in combination with egg white (EW) proteins were measured by standard techniques. Protein-protein interactions were quantified by fitting the oxygen-17 NMR data using a virial expansion. Gel strength of fish myofibrillar (MF) proteins gels treated with EW proteins high in calcium (10 mM CaCl2) was lower than the gel strength of fish myofibrillar (MF) protein gels treated with EW proteins low in calcium (1 mM CaCl2). There was also a marked increase in elasticity (springiness) of fish myofibrillar (MF) protein gels treated with EW proteins low in calcium as compared with fish myofibrillar (MF) protein gels treated with EW proteins high in calcium. The textural data indicate that the addition of either a mixture of sucrose/sorbitol or sorbitol alone was effective in the gel strength of the fish MF/EW gels high in calcium relative to that of the fish MF/EW gels low in calcium. However, both types of fish MF/EW gels exhibit similar cohesiveness in the absence and/or presence of these cryoprotective solutes. A marked decrease in protein-protein interactions was noted in MF/EW gels with increasing calcium concentration. The presence of cryoprotectants appeared to enhance protein-protein interactions of MF/EW gels high in calcium (10 mM). The oxygen-17 NMR data enabled accurate prediction of textural behavior of fish MF/EW gels at various ingredient combinations.
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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