Food-grade emulsions stabilized by marine Antarctic krill (Euphausia superba) proteins with long-term physico-chemical stability

Abstract

The amino acids composition, secondary structure and aggregation profiles of Antarctic krill proteins were characterized. Ability of the proteins to stabilize sunflower oil-based emulsions was firstly evaluated, and further the effects of NaCl concentration, pH values and storage temperatures on their stabilization were investigated. Results showed that the krill proteins contained much balanced essential amino acids compared to some plant proteins, and hydrophobic interactions and disulfide bonds greatly contributed to the development and stabilization of the protein aggregates. Antarctic krill proteins formed emulsions with their particle size less than 20 μm under 3%–4% protein and oil/water ratios of 3:7–5:5. Moreover, higher krill proteins content (≥3%), lower NaCl concentration (≤100 mM) or higher temperatures (≥40 °C) greatly favored the formation of gel-like networks of emulsions. Notably, the emulsions stabilized by 3% Antarctic krill proteins and oil/water ratio of 3:7 could resist the fluctuation of pH (3–9), salt concentration (50–400 mM) and temperatures (4–60 °C). Meanwhile, the emulsions exhibited a comparable long-term stability after 30 days storage compared to the existing proteins or biopolymers-stabilized emulsions. This study expends the knowledges of constructing novel Antarctic krill proteins-stabilized emulsions to unlock the high value-added utilization of marine protein resources in food industry.