Evaluation of Rheological Properties of Pork Myofibrillar Protein Gel and Physicochemical and Textural Properties of Low-Fat Model Sausages Treated with Rhynchosia nulubilis Powders from Different Drying Methods and Their Protein Extract

This study evaluated the rheological properties of pork myofibrillar protein (MP) gel and the physicochemical properties of low-fat model sausages (LFMS) treated with <i>Rhynchosia nulubilis</i> powders (RNPs) obtained through different drying methods. Two experiments were conducted: (1) rheological analysis of MP gels treated with RNPs and their protein extract (PE), and (2) assessment of LFMS properties treated with RNPs and PE. The viscosity of MP treated with freeze- and oven-dried RNPs was higher than that of the control (CTL), while PE-treated MP (MPE) showed lower viscosity. Cooking yields (%) of MPE exceeded those of CTL, although the gel strength of MPE was the lowest (p<0.05). The pH of LFMS ranged from 6.01 to 6.31, with PE-treated LFMS (SPE) exhibiting the lowest pH. SPE demonstrated lower CIE L* and CIE a* values but a higher CIE b* value compared to the reference (REF, soy protein isolate). Cooking loss (%) of CTL was higher than those of the treatments, while expressible moisture (%) was lower in CTL compared to SPE. Additionally, the protein content of LFMS increased with RNP and PE addition. SPE had lower hardness than CTL, but no difference from REF was observed (p>0.05). Therefore, oven-dried RNPs can effectively serve as a fat replacer in LFMS, similar characteristics to those of REF.