@article{yang_rogers_berry_foegeding_2011, title={MODELING THE RHEOLOGICAL PROPERTIES OF CHEDDAR CHEESE WITH DIFFERENT FAT CONTENTS AT VARIOUS TEMPERATURES}, volume={42}, ISSN={["1745-4603"]}, DOI={10.1111/j.1745-4603.2011.00283.x}, abstractNote={ABSTRACTCheddar cheese consists of a gel phase with imbedded fat particles and can be represented as a particle‐filled gel. The storage modulus (G′) of Cheddar cheese containing different fat contents was fitted to 12 theoretical models for particle‐filled gels. Models that included the G′ of fat particles and their interactions best described cheese G′. The estimated G′ of fat particle (Gf′) was larger than that of gel matrix (Gm′) at 10, 15 and 20C, corresponding to a reinforcing effect of fat on cheese G′. However, Gf′ decreased at a faster rate than Gm′ with increasing temperature, resulting in a weakening effect at 25C. Cheese rheological properties were dominated by the solid fat phase at 10 and 15C and showed no significant change with aging. In contrast, cheese G′ at 20 and 25C decreased after aging cheeses for 12 weeks, corresponding to decreases of Gm′ as a result of changes in the protein network.PRACTICAL APPLICATIONSFat is critical to cheese texture. The rheological properties of cheeses depend on the two phases: fat particles and protein gel matrix. However, limited works have been done to quantitatively evaluate the contributions from the two phases. In this article, the rheological properties of Cheddar cheese containing a range of fat content were fitted to 12 mathematical models for particle‐filled gels. The advantages and limitations of these theoretical models were compared. This study extended the application of the mathematical models in Cheddar cheese, showing a quantitative evaluation on the role of fat in cheese rheology. This provides quantitative information for developing fat substitutes to function as fat particles in cheese texture.}, number={5}, journal={JOURNAL OF TEXTURE STUDIES}, author={Yang, Xin and Rogers, Neal Robert and Berry, Tristan Kendricks and Foegeding, Edward Allen}, year={2011}, month={Oct}, pages={331–348} }
 @article{yang_foegeding_2011, title={The stability and physical properties of egg white and whey protein foams explained based on microstructure and interfacial properties}, volume={25}, ISSN={["0268-005X"]}, DOI={10.1016/j.foodhyd.2011.03.008}, abstractNote={The goal of this investigation was to determine if physical models, based on micro-scale (bubbles) and nano-scale (interface) properties, can be used to explain the macroscopic foaming properties of egg white protein (EWP) and whey protein isolate (WPI). Foam properties were altered by adding different amounts of sucrose (4.27–63.6 g/100 mL) and microstructures were observed using confocal laser scanning microscopy and bubbles were quantitatively measured using image analysis. Addition of sucrose decreased the initial bubble size, corresponding to higher foam stability and lower air phase fraction. EWP foams were composed of smaller bubbles and lower air phase fractions than WPI foams. Increased sucrose concentration caused a decreased liquid drainage rate due to a higher continuous phase viscosity and smaller bubble sizes. WPI foams had faster rates for liquid drainage and bubble coarsening than EWP foams. The differences were attributed to faster bubble disproportionation in WPI foams, caused by lower interfacial elasticity and lower liquid phase fractions. The experimentally fitted parameters for foam yield stress did not follow universal trends and were protein type dependent. EWP foams had higher yield stress than WPI foams due to smaller bubble sizes and higher interfacial elasticity. The yield stress of WPI foams increased slightly with addition of sucrose and cannot be accounted for based solely on model parameters. It appears that changes in stability of EWP and WPI foams can be explained based on physical models while unaccounted for protein-specific effects remain regarding foam yield stress.}, number={7}, journal={FOOD HYDROCOLLOIDS}, author={Yang, Xin and Foegeding, E. Allen}, year={2011}, month={Oct}, pages={1687–1701} }
 @article{yang_foegeding_2010, title={Effects of sucrose on egg white protein and whey protein isolate foams: Factors determining properties of wet and dry foams (cakes)}, volume={24}, ISSN={["1873-7137"]}, DOI={10.1016/j.foodhyd.2009.09.011}, abstractNote={The effects of sucrose on the physical properties of foams (foam overrun and drainage ½ life), air/water interfaces (interfacial dilational elastic modulus and interfacial pressure) and angel food cakes (cake volume and cake structure) of egg white protein (EWP) and whey protein isolate (WPI) was investigated for solutions containing 10% (w/v) protein. Increasing sucrose concentration (0–63.6 g/100 mL) gradually increased solution viscosity and decreased foam overrun. Two negative linear relationships were established between foam overrun and solution viscosity on a log–log scale for EWP and WPI respectively; while the foam overrun of EWP decreased in a faster rate than WPI with increasing solution viscosity (altered by sucrose). Addition of sucrose enhanced the interfacial dilational elastic modulus (E′) of EWP but reduced E′ of WPI, possibly due to different interfacial pressures. The foam drainage ½ life was proportionally correlated to the bulk phase viscosity and the interfacial elasticity regardless of protein type, suggesting that the foam destabilization changes can be slowed by a viscous continuous phase and elastic interfaces. Incorporation of sucrose altered the volume of angel food cakes prepared from WPI foams but showed no improvement on the coarse structure. In conclusion, sucrose can modify bulk phase viscosity and interfacial rheology and therefore improve the stability of wet foams. However, the poor stability of whey proteins in the conversion from a wet to a dry foam (angel food cake) cannot be changed with addition of sucrose.}, number={2-3}, journal={FOOD HYDROCOLLOIDS}, author={Yang, Xin and Foegeding, E. Allen}, year={2010}, pages={227–238} }
 @article{yang_berry_foegeding_2009, title={Foams Prepared from Whey Protein Isolate and Egg White Protein: 1. Physical, Microstructural, and Interfacial Properties}, volume={74}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2009.01179.x}, abstractNote={ABSTRACT:  Foams were prepared from whey protein isolate (WPI), egg white protein (EWP), and combinations of the 2 (WPI/EWP), with physical properties of foams (overrun, drainage 1/2 life, and yield stress), air/water interfaces (interfacial tension and interfacial dilatational elasticity), and foam microstructure (bubble size and dynamic change of bubble count per area) investigated. Foams made from EWP had higher yield stress and stability (drainage 1/2 life) than those made from WPI. Foams made from mixtures of EWP and WPI had intermediate values. Foam stability could be explained based on solution viscosity, interfacial characteristics, and initial bubble size. Likewise, foam yield stress was associated with interfacial dilatational elastic moduli, mean bubble diameter, and air phase fraction. Foams made from WPI or WPI/EWP combinations formed master curves for stability and yield stress when normalized according to the above‐mentioned properties. However, EWP foams were excluded from the common trends observed for WPI and WPI/EWP combination foams. Changes in interfacial tension showed that even the lowest level of WPI substitution (25% WPI) was enough to cause the temporal pattern of interfacial tension to mimic the pattern of WPI instead of EWP, suggesting that whey proteins dominated the interface. The higher foam yield stress and drainage stability of EWP foams appears to be due to forming smaller, more stable bubbles, that are packed together into structures that are more resistant to deformation than those of WPI foams.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Yang, Xin and Berry, Tristan K. and Foegeding, E. Allen}, year={2009}, pages={E259–E268} }
 @article{berry_yang_foegeding_2009, title={Foams Prepared from Whey Protein Isolate and Egg White Protein: 2. Changes Associated with Angel Food Cake Functionality}, volume={74}, ISSN={["1750-3841"]}, DOI={10.1111/j.1750-3841.2009.01178.x}, abstractNote={ABSTRACT:  The effects of sucrose on the physical properties and thermal stability of foams prepared from 10% (w/v) protein solutions of whey protein isolate (WPI), egg white protein (EWP), and their combinations (WPI/EWP) were investigated in wet foams and angel food cakes. Incorporation of 12.8 (w/v) sucrose increased EWP foam stability (drainage 1/2 life) but had little effect on the stability of WPI and WPI/EWP foams. Increased stability was not due to viscosity alone. Sucrose increased interfacial elasticity (E ′) of EWP and decreased E′ of WPI and WPI/EWP combinations, suggesting that altered interfacial properties increased stability in EWP foams. Although 25% WPI/75% EWP cakes had similar volumes as EWP cakes, cakes containing WPI had larger air cells. Changes during heating showed that EWP foams had network formation starting at 45 °C, which was not observed in WPI and WPI/EWP foams. Moreover, in batters, which are foams with additional sugar and flour, a stable foam network was observed from 25 to 85 °C for batters made from EWP foams. Batters containing WPI or WPI/EWP mixtures showed signs of destabilization starting at 25 °C. These results show that sucrose greatly improved the stability of wet EWP foams and that EWP foams form network structures that remain stable during heating. In contrast, sucrose had minimal effects on stability of WPI and WPI/EWP wet foams, and batters containing these foams showed destabilization prior to heating. Therefore, destabilization processes occurring in the wet foams and during baking account for differences in angel food cake quality.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Berry, Tristan K. and Yang, Xin and Foegeding, E. Allen}, year={2009}, pages={E269–E277} }