Quality Change Mechanism of High-Moisture and Low-Salt Tibetan Pork Sausage

This study was conducted to investigate the quality formation mechanism of Tibetan pork sausage under high-moisture and low-salt conditions and to clarify the relationship between moisture migration and product quality. It aimed to provide a theoretical basis for overcoming common technical bottlenecks in traditional sausage products, such as high salt content and excessive hardness, and for developing novel meat products with both health attributes and superior quality.

A two-factor interaction experimental design was adopted. Sausage samples were prepared under the following conditions: a fixed salt addition level of 1.5% and a moisture content adjusted in the range of 25% to 50%, and a fixed moisture content of 45% and a salt addition level adjusted in the range of 1.0% to 2.5%. The sausages were systematically analyzed for pH, color, texture, cooking loss, moisture distribution (via low-field nuclear magnetic resonance and imaging), flavor (using an electronic nose and an electronic tongue), and microstructure (via scanning electron microscopy). Sensory evaluation was also performed, and the data were analyzed to comprehensively elucidate the patterns of quality evolution.

Under the fixed salt addition level of 1.5%, the increase in moisture content led to an initial decrease followed by an increase in pH, a significant increase in cooking loss rate, a prolongation in T₂ relaxation time (immobile and free water), and a reduction in texture hardness of up to 49.61%. With the moisture content fixed at 45%, with the decreasing of salt addition, several changes happened. Specifically, no significant change was observed in pH. The cooking loss rate rose, and the T₂ relaxation time increased significantly. Whereas the hydrogen proton density exhibited an initial increase followed by a decrease, the muscle fiber structure underwent a progressive transformation: from initial cracking, to an optimized uniform and dense state, and finally to a rough and disordered morphology. The flavor profile showed significant differences between various treatment groups (P<0.05), whereas no significant differences were found in the taste profile. Comprehensive analysis indicated that the Tibetan pork sausages with a moisture content of 45% and a salt addition level of 1.5% demonstrated optimal performance in terms of color brightness, texture suitability, water retention capacity, and the uniformity and denseness of the microstructure.

In contrast to traditional low-moisture and high-salt formulations, the high-moisture (45%) and low-salt (1.5%) formulation synergistically optimized both the protein network structure and moisture distribution state in Tibetan pork sausage. This approach significantly reduced salt consumption while maintaining suitable texture characteristics, good water-holding stability, a balanced flavor profile, and high sensory acceptability.