Effect of micro- and nano-sized emulsion fillers combined with trans-cinnamaldehyde on the physicochemical and rheological characteristics of myofibrillar protein gels

In this study, we investigated the influence of trans-cinnamaldehyde (CIN) and emulsion size on the physicochemical properties and functionality of emulsion gels. Myofibrillar protein or lecithin emulsions were fabricated with different ratios of canola oil and CIN and different emulsion droplet sizes. The emulsion gels showed a significant dependence on CIN concentration in terms of gel strength and rheological properties because of the improved interaction between proteins and aldehydes through the Schiff base reaction. In addition, the physical properties of the micro-sized emulsion gels were better than those of the nano-sized gels. There was no significant difference in the water-holding capacity. According to the scanning electron and confocal microscopy images, the CIN emulsion gels formed a denser microstructure and had a higher homogeneity with higher CIN concentrations. This suggested that CIN promoted protein cross-linking because the monophenol molecule had fewer structural obstacles. The structural properties were analyzed using Fourier-transform infrared spectroscopy. It was also confirmed that lipid oxidation was inhibited by CIN. The information obtained in this study could be used to develop protein-based products with novel functional properties for use in meat products and in other applications.