Effects of ultrasound on the oxidation and structure of myofibrillar protein in the presence or absence of soybean oil

BACKGROUNDUltrasound is widely used as a novel non-thermal processing technique to improve protein properties. In recent decades, applying ultrasound-assisted emulsification (UAE) to produce protein-stabilized emulsion has attracted people's attention. Instead of applying ultrasound to treat a single protein solution, UAE treatment refers to the use of sonication to a mixture of protein and oil. The purpose of this study was to compare the different effects of ultrasound treatment on the properties of myofibrillar protein (MP) in the presence or absence of soybean oil. A suitable sonication power was selected based on the change in emulsion properties. RESULTS300 W sonication power was selected because of its most effectively decreased emulsion droplet size and increased absolute zeta potential. Sonication more significantly increased the protein carbonyl content and disulfide bonds of the MP-soybean oil sample compared with the MP sample. Due to the presence of oil, ultrasound could unfold more protein molecules, illustrated by a lower alpha-helix content and intrinsic fluorescence intensity, and a higher surface hydrophobicity. Results of liquid chromatography-tandem mass spectrometry illustrated that sonication enhanced the myosin heavy chain and actin content at the soybean oil interface as well as accelerated the myosin light chain to separate from myosin in the MP-soybean oil system. CONCLUSIONUltrasound treatment could lead to a higher level of protein oxidation and greater protein molecule exposure in the MP in the presence of oil system than in the oil-free MP system. (c) 2023 Society of Chemical Industry.