Myofibrillar proteins from beef muscles as gelling ingredients for foods tailored to dysphagia diets

Beef is a high-quality protein source. However, individuals with dysphagia (impaired chewing and swallowing) may be unable to consume it safely, since its firm and fibrous texture increases the risk of choking and aspiration. When extracted under saline conditions, myofibrillar proteins, the major protein fraction of beef muscle, form gels upon heating, making them potential ingredients for texture-modified foods. This study aimed to develop and evaluate myofibrillar protein gels from beef sirloin (Longissimus dorsi) and shoulder clod (Triceps brachii) for use in dysphagia diets. Proteins were extracted with saline buffers, and gels (30, 50 and 70 mg/mL) were formed by heating at 71 °C for 30 min. The gels were evaluated for syneresis, feasibility for dysphagia diets by the International Dysphagia Diet Standardisation Initiative (IDDSI) fork pressure test (manual and instrumental), texture profile analysis, rheological properties (oscillatory, steady shear and creep–recovery tests), amino acids released after in vitro gastrointestinal digestion (INFOGEST 2.0 protocol, HPLC), and extrusion-based 3D printability. Data were analyzed by two-way ANOVA and Tukey's test (P < 0.05). All gels were easily mashed with a fork and did not return to their original shape, meeting IDDSI level 6 (soft and bite-sized) criteria, and showed no syneresis, which favors bolus control during swallowing. All gels behaved rheologically as weak gel-like systems, predominantly elastic (G′ > G″; tan δ = 0.23–0.24) and shear-thinning. Muscle type had a greater effect than protein concentration. The 30 mg/mL sirloin gel formed the most structured network (highest stiffness, G′LVR = 38,074 Pa, and viscosity), whereas shoulder clod gels were the least structured, which may be associated with higher sarcoplasmic protein solubility (12.36% vs. 3.24% in sirloin). After simulated digestion, sirloin gels released more essential amino acids than shoulder clod gels (372.35 vs. 311.76 mg/g), corresponding to 67–86% and 60–73%, respectively, of the essential amino acid content reported for cooked beef. None of the gels was suitable for 3D printing, as they lacked the structural recovery and self-support required after extrusion. In conclusion, beef myofibrillar protein gels meet the physical and nutritional requirements of dysphagia diets and deliver bioaccessible essential amino acids, although the muscle source influences their structure and amino acid release.

Acknowledgments: FAPESP (grant #2023/13732-1) and CAPES (Finance Code 001).