Effect of κ‐carrageenan addition on protein structure and gel properties of salted duck egg white

Abstract

BACKGROUND Salted duck egg white (SDEW) is a major by‐product during salted egg yolk manufacturing. Due to the high salt concentration, SDEW has not been efficiently utilized. Moreover, functional properties of SDEW are altered by salt during pickling. To improve the functional properties, the effect of κ‐carrageenan (κ‐CAR) addition on the protein structure and gel properties of SDEW was investigated in this study. RESULTS The surface hydrophobicity and free sulfhydryl content of SDEW protein increased, while total sulfhydryl content decreased significantly with the addition of κ‐CAR (0.02–0.10%). Fourier‐transform infrared spectroscopy analysis revealed that the relative content of α‐helix and β‐turn decreased, β‐sheet and random coil increased, indicating the variation tendency of protein structure from order to disorder. As κ‐CAR addition increased, the texture profiles including hardness, gumminess, chewiness, springiness, cohesiveness and resilience of SDEW gel were all improved. Water holding capacity increased significantly by 32.33% in the presence of 0.10% κ‐CAR addition. The scanning electron microscopy indicated that the microstructure of SDEW/κ‐CAR mixed gel was more smooth and compact. CONCLUSION The results suggested that adding κ‐CAR can be an effective method to improve gel quality of SDEW. This study is expected to provide theoretical basis for modification of SDEW protein, as well as preparation of food ingredients with better gel properties from SDEW. © 2020 Society of Chemical Industry

Gelation and microstructural properties of ternary composite gel of scallop (Patinopecten yessoensis) protein hydrolysates/κ‐carrageenan/xanthan gum

“…Many reports have indicated the interaction between protein and KC or XG. KC has a good synergistic effect with a variety of proteins, such as whey protein isolate , salted duck egg white (Tang et al, 2020), egg yolk protein (Huang et al, 2021), myofibrillar protein (Zhang et al, 2017), and antarctic krill protein isolated (Zheng et al, 2019). The addition of XG also could enhance gel properties of protein, such as ovalbumin (Souza & Garcia-Rojas, 2016) and whey protein isolate (Geremias-Andrade et al, 2017).…”

Modification methods and applications of egg protein gel properties: A review

“…Hydrophobic interactions, hydrogen bonds, and electrostatic interactions are noncovalent bonds, while disulfide bonds are covalent bonds. The hydrophobic interactions of proteins are influenced by surface hydrophobicity, which can stabilize the protein conformation and contribute to the formation of gel networks (Tang et al., 2020). Thus, the hydrophobic group inside the protein molecule is exposed by external factors to increase the surface hydrophobicity of the protein molecule and promote the formation of the gel.…”

Effect of polysaccharides on the functional properties of egg white protein: A review

“…2015). However, κ‐carrageenan addition decreased relative content of α‐helix and β‐turn and increased β‐sheet and random coil of salted duck egg white (Tang et al., 2020). It may be because duck egg white gels contained many salt ions that changed protein conformation.…”

“…In addition, the egg white gel network also depended on environmental factors such as pH, ionic strength, and temperature. For example, high NaCl concentrations influenced aggregation behavior of duck egg white protein and had adverse effects on its textural properties (Tang et al., 2020). Deng et al., (2020) showed that K + significantly enhanced the gel properties, while Ca 2+ , Zn 2+ , and Fe 3+ were more conducive to formation of polymers to affect gel performance of alkali‐induced EWP.…”