Protein content of amaranth and quinoa starch plays a key role in their ability as Pickering emulsifiers. (15th June 2020)

• Record Type: Journal Article
• Authors: Kierulf, Arkaye; Whaley, Judith; Liu, Weichang; Enayati, Mojtaba; Tan, Chen; Perez-Herrera, Mariana; You, Zheng; Abbaspourrad, Alireza
• Is Part Of: Food chemistry. Volume 315(2020)
• Publication Date: 2020-06-15
• Subjects: Pickering emulsion -- Protein content -- Amaranth and quinoa starch -- Solid surfactants -- Alkaline extraction method -- Octenyl succinic anhydride; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2020.126246
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: We demonstrate an alkaline method to isolate high-protein starch from flour. High-protein starches are good Pickering emulsifiers, even w/o octenyl succinylation. Higher protein content makes smaller droplets w/ greater emulsion index & viscosity. Reducing protein content reduces emulsifying ability, but reducing fat has no effect. Starch's emulsifying ability is affected by pH, w/c highlights protein's key role. Abstract: Growing concerns about the safety of using synthetic surfactants to stabilize food emulsions have inspired a trend towards the use of natural ingredients like starch as alternative food stabilizers in what are called Pickering emulsions. The hydrophilicity of commercially available starches, however, necessitates further chemical treatment to increase their hydrophobicity and emulsifying ability. Here we demonstrate an alkaline isolation method to extract amaranth and quinoa starch from flour while retaining a high protein content, which gives these materials an emulsifying ability comparable to octenyl succinylated starches in the literature. We highlight the key role played by protein by showing that a serial reduction of the protein content leads to a parallel reduction in emulsifying ability, and that pH affects this ability. Our method of retaining proteins naturally present in amaranth and quinoa not only bolsters their nutritional profile but also takes advantage of these proteins' native hydrophobicity for improved emulsification.