Mechanisms of Change in Emulsifying Capacity Induced by Protein Denaturation and Aggregation in Quick-Frozen Pork Patties with Different Fat Levels and Freeze-Thaw Cycles.

Nan Pan,Hong Lv,Wei Wan,Qian Liu,Xin Du,Baohua Kong,Fangfei Li,Xiufang Xia

doi:10.3390/foods11010044

Nan Pan, Hong Lv + Show 6 more

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https://doi.org/10.3390/foods11010044

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Abstract

Herein, we discuss changes in the emulsifying properties of myofibrillar protein (MP) because of protein denaturation and aggregation from quick-frozen pork patties with multiple fat levels and freeze–thaw (F–T) cycles. Protein denaturation and aggregation were confirmed by the significantly increased surface hydrophobicity, turbidity, and particle size, as well as the significantly decreased solubility and absolute zeta potential, of MPs with increases in fat levels and F–T cycles (p < 0.05). After multiple F–T cycles, the emulsifying activity and emulsion stability indices of all samples were significantly reduced (p < 0.05). The emulsion droplets of MP increased in size, and their distributions were dense and irregular. The results demonstrated that protein denaturation and aggregation due to multiple F–T cycles and fat levels changed the distribution of surface chemical groups and particle sizes of protein, thus affecting the emulsifying properties.

Highlights

Quick-frozen patties are a type of emulsion-type comminuted meat product [1]
The results indicated that the interaction between proteins changed from hydrophilic to hydrophobic
With increasing F–T cycles, the structure and conformation of protein molecules were unfolded, and certain hydrophobic groups were exposed to the polar environments of the protein surface step by step, which accelerated the opening of the interior hydrophobic domain and subsequently enhanced the hydrophobicity of the protein surface [3]

Summary

Introduction

Quick-frozen patties are a type of emulsion-type comminuted meat product [1] They are usually composed of muscle proteins, fat particles, water, salt, and nonmeat ingredients combined by mincing, chopping, mixing, molding, quick freezing, and frozen storage. MP acts as an emulsifier to maintain the balance of protein–fat and protein–water by adsorbing on the surface of fat globules to form the interfacial protein film [1]. Fat particles are another important ingredient for improving the quality of emulsified meat products [4]. In addition to muscle proteins and fat particles, protein composition, type (such as cereal protein and whey protein), and processing conditions (such as thermal treatment [6], pH [7], mechanical stress [8], and frozen storage [9]) influence the emulsifying properties of proteins

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Conclusion