Pre-treatment by combining atmospheric cold plasma and pH-shifting to prepare pea protein concentrate powders with improved gelling properties

Abstract

Pea proteins are increasingly used as an alternative for soy protein, however, structuring of pea protein remains a challenge due to its low gelling capacity. This study reports a pea protein pre-treatment that combines atmospheric cold plasma (ACP) and pH-shifting to improve pea protein gelling property. Specifically, the pea protein concentrate was treated by ACP at pH 12 for 10 min, followed by pH-shifting to neutral and spray-drying to prepare PPCtreated powders. Although, pea protein concentrate did not form a self-standing gel until 95 °C for 60 min, PPCtreated suspension (14 wt%) formed gels with good mechanical properties (compressive strength: 2.81 kPa) by heating at 70 °C within 10–20 min. The strength of the gel made from PPCtreated was further increased to 3.70 and 5.53 kPa when raising the temperature to 80 and 90 °C, respectively. The protein characterizations revealed that the combined ACP and pH-shifting treatment partially unfolded pea protein by altering the tertiary structure, and then the active species produced by ACP facilitated the formation of protein aggregates with increased surface hydrophobicity. During heating, the aggregates served as active building blocks to form more ordered three-dimensional gel networks via hydrophobic interactions and hydrogen bonding. The greatly increased gel strength and the powder form will allow pea protein to be widely used as a gelling ingredient in many food formulations. The capacity to form gels at a reduced temperature than pea protein denaturation temperature (∼95 °C) will enable food texture development by conventional cooking.