Jump to Main Content
Foam and emulsion properties of potato protein isolate and purified fractions
- Schmidt, Jesper Malling, Damgaard, Henriette, Greve-Poulsen, Mathias, Larsen, Lotte Bach, Hammershøj, Marianne
- Food hydrocolloids 2018 v.74 pp. 367-378
- droplet size, emulsifying, emulsifying properties, emulsions, foaming, hydrocolloids, hydrophobic interaction chromatography, hydrophobicity, ion exchange chromatography, pH, patatin, potato protein, protein isolates, proteinase inhibitors, spray drying, texture
- Spray dried potato protein and specific isolated fractions were used for foaming and emulsification studies. The spray dried protein was separated into a patatin and a protease inhibitor (PI) rich fraction by ion exchange chromatography (IEX), respectively, and these two fractions were purified by hydrophobic interaction chromatography into a low (HIC 1) and a high (HIC 2) hydrophobic fraction. Foam overrun for the spray dried powder and all patatin fractions were highest at pH 3, with gradually lower values at pH 5 and 7, while the PI fractions had highest overrun at pH 5 and equally lower values at pH 3 and 7. Relative foam stability varied from 18 to 78% of the initial foam at pH 3 while lower variation of 67–80% was seen at pH 5 and 7. The HIC fractions did generally perform better than the spray dried powder and IEX fractions, with patatin HIC 1 and HIC 2 having superior performance at pH 3 and PI HIC 2 at pH 5 and 7. Emulsions were characterized by emulsion stability and activity, emulsion droplet size and small scale dynamic rheological measurements. The PI, and especially PI HIC 1 showed poor emulsion properties with low stability, large droplet size and less texture. Interestingly, PI HIC 2 had much better emulsion properties on par with the spray dried powder and patatin, while having a more frequency dependent textural response. Overall, the best emulsion properties were obtained with patatin HIC 2, thus showing the importance of hydrophobicity for protein functionality.