59D-9 |
The effect of Glycerol, Trehalose, Sucrose, and Sorbitol on the thermostability of Bovine Serum Albumin |
S. K. BAIER and D. J. Mc Clements. Food Colloids and Bioploymer Lab, University of Massachusetts, 430 Chenoweth Laboratory, Amherst, MA 01003 The unfolding and aggregation of protein molecules determines many of the desirable attributes of food products, e.g. texture, stability, taste and appearance. Proteins are used in foods that contain a wide variety of different low molecular weight solutes, e.g. sugars and salts. The presence of these solutes can have a large impact on the molecular and functional characteristics of proteins and therefore it is important to systematically characterize their influence. Our objective was to use a combination of calorimetric and rheological techniques to systematically study the influence of different cosolvent systems on the thermal stability of a model globular protein (BSA). An ultrasensitive differential scanning calorimeter (DSC), thermal scanning UV-Visible spectrophotometer and a rheometer were used to monitor the influence of cosolvent type (Glycerol, Trehalose, Sucrose, and Sorbitol), cosolvent concentration (0 – 40 wt%) and temperature (25 – 90oC) on the unfolding of a globular protein (BSA). The calorimeter provided information about the transition enthalpy (DH) and temperature (Tm), whereas the rheometer and spectrophotometer provided information about gelling and aggregation characteristics of the protein as influenced by the cosolvent system. The cosolvent system had a significant impact on the thermal transition temperature of the BSA. Glycerol, sorbitol, sucrose, and trehalose increased the thermal stability of the protein and promoted protein aggregation, which influenced both the appearance and rheology of protein gels. Our results are interpreted in terms of the preferential accumulation or exclusion of cosolvent molecules at the protein interface. This study shows that by using a combination of modern analytical techniques it is possible to obtain fundamental knowledge about the influence of a cosolvent system on protein functionality. A better understanding of protein interactions with specific model cosolvent systems would enable food scientists to design and produce protein-containing foods with desirable organoleptic attributes and shelf life.
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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