The purpose of this study was to investigate effect of physical treatment (ultrasound, U/high pressure homogenization, H/combined treatment, UH or HU) and surfactant (Mogroside V, Mog) on air/water interface adsorption and foaming properties of α-lactalbumin (ALa). Firstly, the binding of Mog and all physical-treated ALa was a static quenching process. Mog had the greatest binding affinity for HU-ALa among all treated samples. U or H treatment could change surface hydrophobicity of ALa/Mog complex. Secondly, at the molar ratio (ALa:Mog) of 1:50, foaming ability (FA) of all ALa samples got the maximum. The sequence of FA in ALa and ALa/Mog complex was listed as follow: HU > U > H > UH. Moreover, foaming stability (FS) of HU-ALa was the highest, followed by H-ALa, U-ALa and UH-ALa. Meanwhile, low concentration Mog increased FS of ALa or UH-ALa, but it reduced FS of H-ALa, U-ALa and HU-ALa. Quartz crystal microbalance with dissipation monitoring (QCM-D) experiment indicated that ALa/Mog complex after U or H treatment was quickly absorbed at air/water interface, compared with the treated ALa, and HU-ALa/Mog had the largest frequency shift. In addition, HU-ALa had the thickest bubble membrane and the highest dissipation shift in all samples, indicating that the absorbed membrane thickness and viscoelasticity of samples was correlated with foam stability. Therefore, U and H treatment synergism with Mog was an effective approach to enhance foam properties of ALa, which indicated that HU-treated ALa/Mog complex could be viewed as the safe and efficient foaming agent applied in food processing.
Jinzhe Li,Yuxuan Huang,Wenjuan Zhang,Akhunzada Bilawal,Narantuya Sukhbaatar,Batsukh Tsembeltsogt,Zhanmei Jiang,Zhishen Mu
In this work, the interaction mechanism, structure and foaming properties between three whey proteins (α-lactalbumin (ALa), β-lactoglobulin (BLg) and bovine serum albumin (BSA)) and Mogroside V (Mog) at pH 7.0 were systematically formulated via multi-spectroscopic analysis and silico methods. Mog quenched the fluorescence of three whey proteins in a static mode. Mog had greater binding affinity for ALa than that for BLg or BSA. Hydrogen bonds, van der Waals force and hydrophobic interaction acted as the primary driven forces in ALa/BLg/BSA-Mog system. Moreover, content of α-helix in ALa and β-sheet in BLg decreased after Mog addition, whereas there was no significant change in the secondary structure of BSA. In addition, hydrophobic crevice in ALa, “bottom of β-barrel” in BLg and interfacial region between two domains in BSA were the binding areas for Mog using molecular docking. Molecular dynamics (MD) simulation further demonstrated that the complex of ALa and Mog possessed the lowest binding free energy and most stable state. Furthermore, compared with single proteins, the foaming ability of protein/Mog complexes were improved. Especially, Ala-Mog attained the highest increase rate. Bubble morphology presented that three whey proteins containing Mog possessed compacter, smaller and even bubbles. This research could establish theoretical basis for the binding mechanism between different food proteins and low weight surfactants. Besides, whey protein-saponin complexes could be served as the novel food-grade foaming agents applied in food industry.
Due to uneven distribution amino acid residues of α-lactalbumin (αLA) at oil-water interface, some measurement should be adopted to improve its interfacial behavior and emulsion stability. Therefore, this study focused on the mechanism of synergy of ultrasound and high pressure homogenization on the emulsion stability and interfacial behaviors of α-lactalbumin with mogroside V (MGV). Four treatments were adopted: ultrasound (US), high pressure homogenization (HPH) and combined treatment (US-HPH and HPH-US). Primarily, emulsion stability of αLA/MGV was analyzed. US-HPH or HPH-US exhibited better emulsion stability than US or HPH. Especially, HPH-US-αLA/MGV emulsion was not stratified at the given time (45 d), which was the most stable emulsion. Moreover, the micromorphology of emulsion showed that MGV and UH/HPH treatment suppressed the aggregation of αLA emulsion droplet. In addition, interfacial adsorption mass and viscoelasticity of physical treated αLA was improved with MGV in the order of HPH-US > US-HPH > US > HPH, specifically, frequency shift (ΔF) and dissipation shift (ΔD) of HPH-US-αLA/MGV was 42.2% and 32.5% higher than that without MGV. This finding may provide a potential approach for obtaining natural and high-efficient protein-based emulsifier in food industry.
危险品化学品经营许可证（带存储）