Yeast protein-based meat analogues: Konjac glucomannan induces the fibrous structure formation by modifying protein structure

Carbohydrate polymers can induce the fibrous structure formation of meat analogues during high-moisture extrusion (HME). In this study, meat analogues were prepared using HME (60% moisture) from yeast protein (YP) and konjac glucomannan (KGM) blends. The impact of KGM (0, 1, 2, 4%, wet basis) addition on the textural, rheological, thermal, and structural properties of high-moisture meat analogues (HMMA) was investigated. The results indicated that KGM strengthened the hardness and chewiness and adjusted the formation and orientation of fibrous structures in HMMA. When the content of KGM reached 1%, the texture of HMMA was optimal. The rheological and thermal results showed that an appropriate KGM content (<4%) enhanced the structure of HMMA, which is consistent with the textural results. In addition, the structural results (ultraviolet-visible spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, surface hydrophobicity, di-sulfide bond content, and X-ray diffraction) demonstrated that KGM increased the protein aggregation, beta-sheet structure, S-S bond content, and ordered degree of HMMA, which were closely related to its texture and fibrous structure. The formation mechanism of KGM-induced fibrous structures in HMMA was preliminary clarified by the protein structure results. Moreover, the study suggested that YP in combination with KGM can be used to produce HMMA with a rich fibrous structure.