@article{mcguffey_otter_zanten_foegeding_2007, title={Solubility and aggregation of commercial alpha-lactalbumin at neutral pH}, volume={17}, ISSN={["1879-0143"]}, DOI={10.1016/j.idairyj.2007.04.003}, abstractNote={The aggregation behavior of two commercial samples of α-lactalbumin (α-La) heated at 95 °C at neutral pH in a complex mineral salt environment was investigated. The objective was to understand the effects of variability between α-La samples and relative concentration of β-lactoglobulin (β-Lg) on aggregate size development, as measured by light scattering and turbidity development. The effect of protein net charge was evaluated with a solubility method and the role of thiol groups was evaluated by reaction with DTNB. The sample with the highest level of β-Lg had higher solubility at pH 6.75 and 6.8, yielded more reactive thiol groups, had a 25% faster first-order rate constant, and formed spherical aggregates with a much higher molecular weight than those produced in the sample containing less β-Lg. Adding increasing quantities of β-Lg to the samples generally decreased reversibility and altered the aggregation process; however, other factors appear to be involved in determining aggregate properties.}, number={10}, journal={INTERNATIONAL DAIRY JOURNAL}, author={McGuffey, Matthew K. and Otter, Donald E. and Zanten, John H. and Foegeding, E. Allen}, year={2007}, month={Oct}, pages={1168–1178} }
 @article{mcguffey_epting_kelly_foegeding_2005, title={Denaturation and aggregation of three alpha-lactalbumin preparations at neutral pH}, volume={53}, ISSN={["1520-5118"]}, DOI={10.1021/jf048863p}, abstractNote={The denaturation and aggregation of reagent-grade (Sigmaalpha-La), ion-exchange chromatography purified (IEXalpha-La), and a commercial-grade (Calpha-La) alpha-lactalbumin were studied with differential scanning calorimetry (DSC), polyacrylamide gel electrophoresis, and turbidity measurement. All three preparations had similar thermal denaturation temperatures with an average of 63.7 degrees C. Heating pure preparations of alpha-lactalbumin produced three non-native monomer species and three distinct dimer species. This phenomenon was not observed in Calpha-La. Turbidity development at 95 degrees C (tau95 degrees C) indicated that pure preparations rapidly aggregate at pH 7.0, and evidence suggests that hydrophobic interactions drove this phenomenon. The Calpha-La required 4 times the phosphate or excess Ca2+ concentrations to develop a similar tau95 degrees C to the pure preparations and displayed a complex pH-dependent tau95 degrees C behavior. Turbidity development dramatically decreased when the heating temperature was below 95 degrees C. A mechanism is provided, and the interrelationship between specific electrostatic interactions and hydrophobic attraction, in relation to the formation of disulfide-bonded products, is discussed.}, number={8}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={McGuffey, MK and Epting, KL and Kelly, RM and Foegeding, EA}, year={2005}, month={Apr}, pages={3182–3190} }
 @article{foegeding_davis_doucet_mcguffey_2002, title={Advances in modifying and understanding whey protein functionality}, volume={13}, ISSN={["1879-3053"]}, DOI={10.1016/S0924-2244(02)00111-5}, abstractNote={Whey protein ingredients are used for a variety of functional applications in the food industry. Each application requires one or several functional properties such as gelation, thermal stability, foam formation or emulsification. Whey protein ingredients can be designed for enhanced functional properties by altering the protein and non-protein composition, and/or modifying the proteins. Modifications of whey proteins based on enzymatic hydrolysis or heat-induced polymerization have a broad potential for designing functionality for specific applications. The effects of these modifications are demonstrated by discussing how they alter gelation and interfacial properties.}, number={5}, journal={TRENDS IN FOOD SCIENCE & TECHNOLOGY}, author={Foegeding, EA and Davis, JP and Doucet, D and McGuffey, MK}, year={2002}, month={May}, pages={151–159} }
 @article{mcguffey_foegeding_2001, title={Electrostatic effects on physical properties of particulate whey protein isolate gels}, volume={32}, ISSN={["1745-4603"]}, DOI={10.1111/j.1745-4603.2001.tb01049.x}, abstractNote={Physical properties of particulate whey protein isolate gels formed under varying electrostatic conditions were investigated using large strain rheological and microstructural techniques. The two treatment ranges evaluated were adjusting pH (5.2‐5.8) with no added NaCl and adjusting the NaCl (0.2‐0.6 M) at pH 7. Gels (10% protein w/v) were formed by heating at 80C for 30 min. The large strain properties of fracture strain (γf), fracture stress (σf), and a measure of strain hardening (R0.3) were determined using a torsion method. Gel microstructure was evaluated using scanning electron microscopy (SEM) and gel permeability (Bgel). Overlaying σf and γf curves for pH and NaCl treatments demonstrated an overlap where gels of equal σf and γf could be formed by adjusting pH or NaCl concentration. The high fracture stress (σf∼ 23 kPa and γf∼ 1.86) pair conditions were pH 5.47 and 0.25 M NaCl, pH 7.0. The low fracture stress (σf∼ 13 kPa and γf∼ 1.90) pair conditions were pH 5.68 and 0.6 M NaCl, pH 7.0. The 0.25 M NaCl, pH 7 treatment demonstrated higher R0.3 values than the pH 5.47 treatment. When the sulfhydryl blocker n‐ethylmaleimide was added at 2 mM to the 0.25 M NaCl, pH 7 gel treatment, its rheological behavior was NSD (p>0.05) to the pH 5.47 gel treatment, indicating disulfide bond formation regulated strain hardening. Altering surface charge or counterions, and disulfide bonding, was required to produce gels with similar large strain rheological properties. An increase in gel permeability coincided with an increase in pore size as observed by SEM, independent of rheological properties. This demonstrated that at the length scales investigated, microstructure was not linked to changes in large strain rheological properties.}, number={4}, journal={JOURNAL OF TEXTURE STUDIES}, author={McGuffey, MK and Foegeding, EA}, year={2001}, month={Nov}, pages={285–305} }
 @article{vardhanabhuti_foegeding_mcguffey_daubert_swaisgood_2001, title={Gelation properties of dispersions containing polymerized and native whey protein isolate}, volume={15}, ISSN={["1873-7137"]}, DOI={10.1016/S0268-005X(00)00062-X}, abstractNote={Whey protein polymers (WP-polymers) were prepared by heating whey protein isolate below the critical concentration for gelation at neutral pH and low salt conditions. The effects of WP-polymers and salt types (CaCl2 or NaCl) on rheological properties (large-strain and small-strain analysis), water holding properties, turbidity and microstructure of heat-induced whey protein isolate gels were investigated. Replacement of native whey protein isolate with WP-polymers increased fracture stress, fracture modulus, held water, and the translucency of gels. With both salt types, the addition of WP-polymers changed the gel structure from particulate to fine-stranded. However, the effect of WP-polymers on rheological properties was salt specific. Addition of 20–100% WP-polymers in the presence of 10 mM CaCl2 caused a continued increase in fracture stress. In contrast, protein dispersions containing 30 mM NaCl did not form self-supporting gels when ≥60% WP-polymers were added. Dispersions containing 200 mM NaCl formed self supporting gels at all levels of WP-polymer addition but fracture stresses for gels containing 20–100% WP were similar. Dispersions containing 80% WP-polymers and 200 mM NaCl had lower gel points (time and temperature) than dispersions with 80% WP-polymers and 10 mM CaCl2. It appeared that CaCl2 was more effective in increasing gel fracture stress while NaCl was more effective in decreasing gelation time. Different gel properties may be prepared by altering the amount of WP-polymers and salt types.}, number={2}, journal={FOOD HYDROCOLLOIDS}, author={Vardhanabhuti, B and Foegeding, EA and McGuffey, MK and Daubert, CR and Swaisgood, HE}, year={2001}, month={Mar}, pages={165–175} }