A review on the utilization of flaxseed protein as interfacial stabilizers for food applications

Abstract

Flaxseed is one of the main cultivated economic oil crops in the world, with a global output of $3.06 million tons. Its residual meal, after oil industrial processing, is rich in protein (35%-40%). However, flaxseed protein is mainly used for feed and its processing efficiency is low. The potential for high-value utilization of flaxseed protein is far from being excavated. Interface dominated-colloidal systems, such as emulsions and foams, are widely available and have extensive applications in food products. Flaxseed protein possesses high contents of hydrophobic amino acids and sulfur-containing amino acids, relatively ordered secondary structures, tunable structural properties, and acceptable interfacial behaviors. These characteristics give it the potential to effectively stabilize food emulsions and foams. By modifications of flaxseed proteins, such as physical treatment and the complexation with polysaccharides and polyphenols, their structural properties and interfacial behaviors can be regulated, therefore, leading to the enhancement of emulsifying and foaming properties. In this review article, the fractionation, composition, and structure of flaxseed protein are detailed summarized. Then, the interfacial behaviors of flaxseed protein and their control approach are highlighted. Additionally, the emulsions and foams stabilized by flaxseed protein-based amphiphilic systems and their applications in food processing are emphasized.

Protein Fractions from Flaxseed: The Effect of Subsequent Extractions on Composition and Antioxidant Capacity

“…Protein surface hydrophobicity (H o ) : Higher surface hydrophobicity H o shows that more hydrophobic patches are outside protein molecules. Its value is valuable for studying protein aggregation behaviours and interfacial properties [ 6 ].…”

“…Due to the growing interest of researchers and the food industry in the application of flaxseed protein as emulsifiers [ 6 , 8 , 55 ], we investigated the ability of the flaxseed protein fractions to inhibit oxidation in the emulsion system (protective effect). CD and CT contents were monitored in oil extracted from the emulsion after 24 h of incubation at 40 °C.…”

“…The biological value of flaxseed protein is also significant compared to other plant proteins. Their essential amino acid composition and digestibility are comparable to pea protein and soy protein [ 5 , 6 ]. The flaxseed protein-derived peptides (products of their hydrolysis) showed various biological activities, such as antioxidant capacity, angiotensin-converting enzyme inhibition, antibacterial activity, anti-inflammatory and anti-diabetic effects [ 7 ].…”

“…Moreover, the flaxseed protein’s primary structure, relatively ordered secondary structure, tunable structural properties and suitable interfacial behaviours indicate that their isolates and concentrates can exhibit interesting functional properties for food production [ 8 ]. They include foaming and emulsifying properties [ 6 ]. All these nutritional and functional benefits encourage researchers to focus on methods of efficient extraction and isolation or concentration of flaxseed proteins [ 9 , 10 ].…”

“…Although flaxseed contains significant amounts of SDG and phenolic acids, it remains a question whether their extraction together with flaxseed proteins is efficient and how much they participate in the antioxidant activity of the received protein fractions. Recent studies focused on the extraction process and structural modification of flaxseed proteins to improve their functionalities, e.g., emulsifying properties [ 6 ]. Some researchers also studied the effect of these processes on the antioxidant activity of flaxseed proteins [ 11 , 20 ] using various analytical assays, e.g., spectrophotometric 2,2-diphenyl-1-picryl-hydrazyl radical (DPPH • ) or ferric reducing antioxidant power (FRAP) assays.…”