Enhancing tenderness of Nelore (Bos indicus) beef through high-intensity ultrasound and papain: An integrative instrumental, microstructural, and sensory evaluation

de Jesus S.M.; do Vale J.P.S.; Galliani M.F.; de Araújo C.D.L.; Castro M.P.P.; Villanueva N.D.M.; Selani M.M.; Castillo C.J.C. · Meat Science (2026) · DOI: 10.1016/j.meatsci.2026.110182

Resumen

Beef from Nelore cattle (Bos indicus) is often characterized by high toughness, particularly when exhibiting a normal ultimate pH (5.4 ≤ pH < 5.8). This study investigated the individual and combined effects of papain and high-intensity ultrasound (HIU) on the physicochemical, microstructural, and sensory properties of normal-pH Nelore beef, with emphasis on tenderization mechanisms and treatment sequence. Six treatments were applied to beef steaks: control (C), papain injection (PI), ultrasound (US), PI followed by US (PIUS), US followed by PI (USPI), and PI followed by 12 h of intermediate storage before US (PI+US). All treatments containing papain significantly reduced Warner–Bratzler shear force (WBSF) and texture profile analysis (TPA) hardness compared with the control. Based on these results, PI, USPI, and PI+US were selected for mechanistic evaluation. Shear force decreased from 83.2 N in the control to 55.4 N in PI+US, 44.3 N in PI, and 40.0 N in USPI. Papain-treated samples exhibited higher myofibrillar fragmentation index and protein solubility, indicating that proteolysis was the primary mechanism responsible for structural disorganization of muscle fibers. These findings were supported by microstructural observations and reductions in hardness, chewiness, and fibrousness detected in the sensory profile. In consumer acceptance tests, USPI obtained the highest scores for tenderness and overall liking. Overall, papain was the main driver of tenderization, whereas application sequence influenced selected texture attributes. Although USPI exhibited lower shear force values and greater consumer acceptance, its effects were not statistically superior to papain alone, suggesting limited additional benefits of HIU combined with enzymatic tenderization.

Instituciones: Universidad Católica Sedes Sapientiae