Abstract
The objective of the present study was to examine the structural and functional changes of β-conglycinin exposed to oxidizing radicals produced by FeCl3/H2O2/ascorbic acid hydroxyl radical-generating system (HRGS) for 3 h at room temperature. Increasing H2O2 concentrations resulted in a loss of histidine residues, lysine residues, and available lysine, which was accompanied by the formation of protein carbonyls and disulphide bonds (p < 0.05). Changes in secondary structure, surface hydrophobicity, and intrinsic fluorescence indicated that hydroxyl radicals had induced protein unfolding and conformational alterations. Results from SDS-PAGE implied that a small amount of protein cross-linkages produced by oxidative incubation. The emulsifying properties of β-conglycinin were gradually improved with the increasing extent of oxidation. The structural changes above contributed to the reduction of potential allergenicity of β-conglycinin, as verified by specific ELISA analysis. These results suggest that moderate oxidation could partially improve the protein functional properties and reduced the potential allergy of protein, providing guidance for effective use of moderately oxidized soy protein in the industry.
Highlights
Soybean protein, which accounts for about 40% of the dry weight of soybean seeds, is widely used as an important food ingredient in consumer diets due to its nutritional quality, functional characteristics, and quantity among seed legume proteins [1]
Protein oxidation is the structural modification of a protein that is induced either directly by reactive oxygen species (ROS) or indirectly by secondary by-products generated from oxidative stress [6]
Carbonyl groups are generated in proteins by ROS mainly through two pathways: (1) direct oxidative attacks on the side chains of susceptible amino acid residues, such as lysine, arginine, and proline residues, whose NH- or NH2 - groups are vulnerable to ·OH oxidative attack and will transform into carbonyl groups [23]; (2) the cleavage of the protein backbone both by the α-amidation pathway occurring on α-carbon and β-scission reactions on the β-position [24]
Summary
Soybean protein, which accounts for about 40% of the dry weight of soybean seeds, is widely used as an important food ingredient in consumer diets due to its nutritional quality, functional characteristics, and quantity among seed legume proteins [1]. The functional properties of soy protein applied in the food industry have involved thickening, water absorption, emulsification, gelling, and foaming activities [2]. These properties vary with protein processing and storage conditions such as ionic strength, pH, temperature, and pressure, among others [3,4]. Protein oxidation is the structural modification of a protein that is induced either directly by reactive oxygen species (ROS) or indirectly by secondary by-products generated from oxidative stress [6]. ROS mainly include free radicals (·OH, O2 − , etc.) and non-radical species (H2 O2 and ROOH)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
