@article{davis_doucet_foegeding_2005, title={Foaming and interfacial properties of hydrolyzed beta-lactoglobulin}, volume={288}, ISSN={["1095-7103"]}, DOI={10.1016/j.jcis.2005.03.002}, abstractNote={β-lactoglobulin (β-lg) was hydrolyzed with three different proteases and subsequently evaluated for its foaming potential. Foam yield stress (τ0) was the primary variable of interest. Two heat treatments designed to inactivate the enzymes, 75 °C/30 min and 90 °C/15 min, were also investigated for their effects on foam τ0. Adsorption rates and dilatational rheological tests at a model air/water interface aided data interpretation. All unheated hydrolysates improved foam τ0 as compared to unhydrolyzed β-lg, with those of pepsin and Alcalase 2.4L® being superior to trypsin. Heat inactivation negatively impacted foam τ0, although heating at 75 °C/30 min better preserved this parameter than heating at 90 °C/15 min. All hydrolysates adsorbed more rapidly at the air/water interface than unhydrolyzed β-lg, as evidenced by their capacity to lower the interfacial tension. A previously observed relationship between interfacial dilatational elasticity (E′) and τ0 was generally confirmed for these hydrolysates. Additionally, the three hydrolysates imparting the highest τ0 not only had high values of E′ (approximately twice that of unhydrolyzed β-lg), they also had very low phase angles (essentially zero). This highly elastic interfacial state is presumed to improve foam τ0 indirectly by improving foam stability and directly by imparting resistance to interfacial deformation.}, number={2}, journal={JOURNAL OF COLLOID AND INTERFACE SCIENCE}, author={Davis, JP and Doucet, D and Foegeding, EA}, year={2005}, month={Aug}, pages={412–422} }
 @article{doucet_foegeding_2005, title={Gel formation of peptides produced by extensive enzymatic hydrolysis of beta-lactoglobulin}, volume={6}, ISSN={["1526-4602"]}, DOI={10.1021/bm0492273}, abstractNote={The purpose of the present study was to identify which peptides were responsible for enzyme-induced gelation of extensively hydrolyzed beta-lactoglobulin with Alcalase in order to gain insight into the mechanism of gelation. Dynamic rheology, aggregation measurements, isoelectrofocusing as well as chromatography and mass spectrometry were used to understand the gel formation. A transparent gel was formed above a critical concentration of peptides while noncovalently linked aggregates appear with increasing time of hydrolysis. Extensive hydrolysis was needed for gelation to occur as indicated by the small size of the peptides. Isoelectrofocusing was successful at separating the complex mixture, and 19 main peptides were identified with molecular weight ranging from 265 to 1485 Da. Only one fragment came from a beta-sheet rich region of the beta-lactoglobulin molecule, and a high proportion of peptides had proline residues in their sequence.}, number={2}, journal={BIOMACROMOLECULES}, author={Doucet, D and Foegeding, EA}, year={2005}, pages={1140–1148} }
 @article{doucet_gauthier_otter_foegeding_2003, title={Enzyme-induced gelation of extensively hydrolyzed whey proteins by Alcalase: Comparison with the plastein reaction and characterization of interactions}, volume={51}, ISSN={["1520-5118"]}, DOI={10.1021/jf026041r}, abstractNote={Extensive hydrolysis of whey protein isolate by Alcalase 2.4L produces a gel. The objectives of this study were to compare enzyme-induced gelation with the plastein reaction by determining the types of interactions involved in gelation. The average chain length of the peptides did not increase during hydrolysis and reached a plateau after 30 min to be approximately 4 residues, suggesting that the gel was formed by small molecular weight peptides held together by non-covalent interactions. The enzyme-induced gel network was stable over a wide range of pH and ionic strength and, therefore, showed some similarities with the plastein reaction. Disulfide bonds were not involved in the gel network. The gelation seems to be caused by physical aggregation, mainly via hydrophobic interactions with hydrogen bonding and electrostatic interactions playing a minor role.}, number={20}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Doucet, D and Gauthier, SF and Otter, DE and Foegeding, EA}, year={2003}, month={Sep}, pages={6036–6042} }
 @article{doucet_otter_gauthier_foegeding_2003, title={Enzyme-induced gelation of extensively hydrolyzed whey proteins by Alcalase: Peptide identification and determination of enzyme specificity}, volume={51}, ISSN={["1520-5118"]}, DOI={10.1021/jf026242v}, abstractNote={Extensive hydrolysis of whey protein isolate by Alcalase was shown to induce gelation mainly via hydrophobic interactions. The aim of this work was to characterize the peptides released in order to better understand this phenomenon. The apparent molecular mass distribution indicated that aggregates were formed by small molecular mass peptides (<2000 Da). One hundred and thirty peptides with various lengths were identified by reversed-phase high-performance liquid chromatography coupled with electrospray ionization mass spectrometry. Alcalase was observed to have a high specificity for aromatic (Phe, Trp, and Tyr), acidic (Glu), sulfur-containing (Met), aliphatic (Leu and Ala), hydroxyl (Ser), and basic (Lys) residues. Most peptides had an average hydrophobicity of 1-1.5 kcal/residue and a net charge of 0 at the pH at which gelation occurred (6.0). Therefore, an intermolecular attractive force such as hydrophobic interaction suggests the formation of aggregates that further leads to the formation of a gel.}, number={21}, journal={JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY}, author={Doucet, D and Otter, DE and Gauthier, SF and Foegeding, EA}, year={2003}, month={Oct}, pages={6300–6308} }
 @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{doucet_gauthier_foegeding_2001, title={Rheological characterization of a gel formed during extensive enzymatic hydrolysis}, volume={66}, ISSN={["1750-3841"]}, DOI={10.1111/j.1365-2621.2001.tb04626.x}, abstractNote={ABSTRACT Extensive hydrolysis of whey protein isolate (WPI) by Alcalase 2.4L® caused a dramatic increase in turbidity and viscosity. A gel was formed after the degree of hydrolysis was ≥ 18%, coinciding with < 16%β‐lactoglobulin and < 4%α‐lactalbumin remaining unhydrolyzed. Heat‐induced and enzyme‐induced WPI gels were compared. Frequency and strain dependence indicated that both gels could be considered as strong, physical gels.}, number={5}, journal={JOURNAL OF FOOD SCIENCE}, author={Doucet, D and Gauthier, SF and Foegeding, EA}, year={2001}, pages={711–715} }