Effect of Flaxseed Gum-Linseed Oil Emulsion as a Fat Substitute on the Quality Characteristics of Emulsified Sausage

In order to reduce the content of saturated fat in emulsified sausage, the effects of using flaxseed gum-linseed oil (FG-LO) emulsion to replace pork backfat at different proportions (25%, 50%, 75% and 100%) on the color, cooking loss, emulsion stability, texture, moisture distribution, lipid oxidation, microstructure and sensory quality of emulsified sausage were investigated. The emulsified sausage without fat replacement was used as control. The brightness (L* value) increased significantly (P < 0.05), and the redness (a* value) decreased significantly (P < 0.05) in the fat replacement groups when compared with the control group; however, the yellowness (b* value) did not significantly change (P > 0.05), and there was no obvious difference in the color observed by the naked eye. The lowest cooking loss and water loss were observed at replacement proportions of 100% and 75%, respectively, while the fat loss had no significant changes at different replacement proportions (P > 0.05). As the replacement level of fat increased, the hardness decreased gradually and the texture became soft, indicating that fat replacement improved the texture of emulsified sausage. After adding FG-LO emulsion, emulsified sausage exhibited the conversion of free water to immobilized water, indicating that FG could interact with meat proteins to form a three-dimensional network structure to lock water molecules, thus enhancing the water-holding capacity. The extent of lipid oxidation was enhanced by the addition of FG-LO emulsion. The results of scanning electron microscopy (SEM) showed that the microstructure of the emulsified sausage with a replacement level of 25% was the most uniform and exquisite, with smaller pores. The sensory evaluation results showed that only the 100% replacement group was significantly different from the control group in terms of texture and overall acceptability (P < 0.05). The results of principal component analysis (PCA) showed that the emulsified sausage with 25% fat replacement was the most similar to the control group. Collectively, 75% fat replacement could reduce the cooking loss, increase the water-holding capacity (WHC), and result in the best emulsion stability and softer texture without causing any significant difference in the sensory quality of emulsified sausage.