Abstract
Ovalbumin (OVA) is an important protein emulsifier. However, it is unstable near the isoelectric point pH, which limits its applications in the food industry. Polysaccharides may be explored to tackle this challenge by improving its pH-dependent instability. In this work, carboxymethyl cellulose (CMC) was used as a model polysaccharide to mix with OVA near its isoelectric point (pH 4.7) with subsequent mild heating at 60 °C for 30 min. The molecular interactions between OVA and CMC were comprehensively studied via a series of characterizations, including turbidity, zeta potential, intrinsic fluorescence, surface hydrophobicity, circular dichroism (CD) spectra and Fourier transform infrared spectroscopy (FTIR). The droplet sizes of the emulsions prepared by OVA-CMC were measured to analyze emulsifying property and stability. The results indicated that free OVA was easily aggregated due to loss of surface charges, while complexing with CMC significantly inhibited OVA aggregation before and after heating owing to the strong electrostatic repulsion. In addition, OVA exposed more hydrophobic clusters after heating, which resulted in the growth of surface hydrophobicity. Altogether, the heated OVA-CMC complexes presented the best emulsifying property and stability. Our study demonstrated that complexing OVA with CMC not only greatly improved its physicochemical properties but also significantly enhanced its functionality as a food-grade emulsifying agent, expanding its applications in the food industry, as development of emulsion-based acidic food products.
Highlights
Ovalbumin (OVA) is an important protein emulsifier
The existence of carboxymethyl cellulose (CMC) could significantly inhibit the aggregation of OVA due to the strong electrostatic repulsions as reflected by their zeta potential values being greater than −30 mV
It was obvious to see that the OVA-CMC complex became opaque at all conditions, as shown in Fig. 1a, suggesting that the intermolecular interactions between OVA and CMC led to the formation of a stable colloidal system
Summary
Ovalbumin (OVA) is an important protein emulsifier It is unstable near the isoelectric point pH, which limits its applications in the food industry. It is well known that charged polysaccharides can reduce the sensitivity of protein solutions against ionic strength and inhibit the aggregation of the proteins From these facts, we hypothesize that heating OVA-CMC complex may enhance the emulsifying property and improve the emulsion stability under a wide range of pH conditions, especially at the isoelectric point of OVA. This study is aimed to demonstrate the protective effect of polysaccharides on protein-stabilized emulsions and provide some guidance for tackling the thermal instability of proteins in the preparation of acidic and heated food products
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
