Effects of Citrus Fiber and Inulin Addition on the Lamb Protein Structure and Mince Quality

In this study, the effects of adding citrus fiber (0.5%, 1.0%, 1.5%, and 2.0%) and inulin (2.0%, 3.0%, 4.0%, and 5.0%) were investigated on the lamb mince quality, water distribution, texture, the protein conformation and the microstructure of lamb protein. Results showed that adding 2.0% citrus fiber significantly increased the disulfide bond content (by 12%) and hydrophobic interactions (by 14%), along with increments in the β-folding content (increment of 8.14%) and irregular curling content (increment of 1.29%). The incorporation of 2.0% citrus fiber facilitated protein cross-linking through disulfide bonding, which elevated the immobilized water fraction. This structural modification promoted the development of a continuous three-dimensional protein network characterized by enhanced density and molecular ordering. The structural modifications induced by 2.0% citrus fiber supplementation significantly enhancd water-holding capacity and textural hardness within the meat matrix (P<0.05). The addition of 3.0% inulin significantly augmented β-sheet content by 8.68% (P<0.05) while inducing a marginal 0.31% increase in random coil structures, concomitant with a statistically significant improvement in water-holding capacity. However, unlike citrus fibers, 3.0% inulin addition promoted the exposure of tryptophan residues and had no significant effect on disulfide bonds and tyrosine residues (P>0.05). In summary, both 2.0% citrus fiber and 3.0% inulin supplementation demonstrated beneficial structural modifications in meat proteins, effectively improving water-holding capacity of minced meat and enhancing the quality of meat products.