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

Abstract

Ultrasound 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 the myofibrillar protein (MP) in the presence or absence of soybean oil. A suitable sonication power was selected based on the change in emulsion properties. The 300W sonication power was selected due to 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 than MP sample. Due to the existence of oil, ultrasound could unfold more protein molecules illustrated by a lower α-helix content and intrinsic fluorescence intensity, and a higher surface hydrophobicity. LC-MS/MS results 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. In summary, ultrasound treatment could lead to a higher level of protein oxidation and more protein molecule exposure in the MP with the presence of oil system than in the oil-free MP system. This article is protected by copyright. All rights reserved.