Effects of combined treatment with ultrasound and pH shifting on foaming properties of chickpea protein isolate

Modifying the physicochemical properties, solubility and foaming capacity of milk proteins by ultrasound-assisted alkaline pH-shifting treatment

This study investigated the effects of different treatment of alkaline pH-shifting on milk protein concentrate (MPC), micellar casein concentrate (MCC) and whey protein isolate (WPI) assisted by the same ultrasound conditions, including changes in the physicochemical properties, solubility and foaming capacity. The solubility of milk proteins had a significant increase with gradual enhancement of ultrasound-assisted alkaline pH-shifting (p < 0.05), especially for MCC up to 99.50 %. Also, treatment made a significant decline in the particle size of MPC and MCC, as well as the turbidity of the proteins (p < 0.05). The foaming capacity of MPC, MCC, and WPI was all improved, especially at pH 11, and at this pH, the milk protein also showed the highest surface hydrophobicity. The best foaming capacity at pH 11 was the result of the combined effect of particle size, potential, protein conformation, solubility, and surface hydrophobicity. In conclusion, ultrasound-assisted pH-shifting treatment was found to be effective in improving the physicochemical properties and solubility and foaming capacity of milk proteins, especially MCC, with promising application prospect in food industry.

Effects of enzymatic cross-linking combined with ultrasound on the oil adsorption capacity of chickpea protein

In order to improve the oil adsorption capacity of chickpea protein, enzymatic cross-linking combined ultrasound was used to modify chickpea protein. Electrophoretic results showed that enzymatic cross-linking made the protein bands thinner, but ultrasound had no significant effect. The oil adsorption capacity of chickpea protein increased from 1.88 to 2.43 g/g; the surface hydrophobicity increased from 3933 to 4575; the zeta potential and emulsification performance were improved.After enzymatic cross-linking, the content of the free sulfhydryl group and emulsifying stability were decreased, and the particle size and the content of disulfide bonds were increased.After ultrasonic treatment, these properties showed an opposite trend. Fourier Transform Infrared Spectroscopy showed that β-turn and random coil increased, the structure of protein became more loose and disordered. These results indicate that enzymatic cross-linking combined with ultrasound improves the functional properties of chickpea protein and extends its application.

Recent advances in modified food proteins by high intensity ultrasound for enhancing functionality: Potential mechanisms, combination with other methods, equipment innovations and future directions

High intensity ultrasound (HIU) is an efficient and green technology that has recently received enormous research attention for modification of food proteins. However, there are still several knowledge gaps in the possible mechanisms, synergistic effects of HIU with other strategies and improvement of HIU equipment that contribute to its application in the food industry. This review focuses on the recent research progress on the effects and potential mechanisms of HIU on the structure (including secondary and tertiary structure) and functionality (including solubility, emulsibility, foamability, and gelability) of proteins. Furthermore, the combination methods and innovations of HIU equipment for proteins modification in recent years are also detailed. Meanwhile, the possible future trends of food proteins modification by HIU are also considered and proposed.