High pressure modification of egg components: Exploration of calorimetric, structural and functional characteristics

• High-pressure treatment causes structural modification that in turns changes functional properties of egg components.
• Increasing pressure and time level cause a higher level of protein aggregation that leads to gelation and aggregation.
• Pressure processing can be used to cause an induced transition of the liquid sample to semi-viscous, and further gel, and this induced transition can be suited for a variety of commercial food applications.
• Pressure induced structure modification changes the foaming behavior, product appeal by changing color and viscosity; these are of high importance in food product applications.

The effects of high pressure (HP) treatment on the thermal, rheological and functional properties of various egg components (whole liquid egg and liquid egg white) were studied as a function of increasing pressure level and treatment time. Differential scanning calorimetry (DSC) and rheometric analysis were utilized to evaluate the extent of protein denaturation and liquid-gel transformation details (G′, G″). Overall, HP-treated samples exhibited predominantly solid-like (G′ > G″) behavior in the frequency range employed (0.1–10 Hz). Pressure level (350–550 MPa) and treatment time (5–15 min) contributed significantly towards modification of liquid samples to partial gel formation. The highest level of pressure treatment (550 MPa for 15 min) was sufficient to cause complete gelatinization. Egg components exhibited a gradual liquid–solid gel transformation as they coagulated/denatured. Corresponding changes were observed in the flow behavior with increasing consistency behavior (m value) and decreasing flow behavior index (n value) showing pseudoplastic behavior. Functional properties like foaming ability, color and viscosity changed with alteration of rheological/structural properties for liquid egg white; however, whole liquid egg showed fewer significant changes (p < 0.05).Industrial relevanceEgg is known as a multifunctional food ingredient, and it plays a significant role in improving the functional profile of other finished foods. High-pressure processing can change the flow behaviour and structure by causing denaturation of proteins. These structural changes further induce transformation in the functional behavior of eggs like color, foaming and viscosity that is of prime importance in the food industry. Hence, evaluation of pressure processing conditions for modifying the egg functionality will help in developing egg and egg products with improved functionality.