Multiscale Investigation of the Structural and Interactional Dynamics Between Monascus Pigment and Plant Proteins...

The color of plant-based meat analogs (PBMA) is a key factor in consumer acceptance. Natural pigments can be used to enhance their appearance and realism. This study explored the interactions between Monascus pigment (MP) and soybean protein isolate (SPI), pea protein isolate (PPI), and soybean protein concentrate (SPC) during the extrusion process, as well as their effects on protein texturization. Through dynamic sampling and the integration of multiple analytical techniques, the study found that MP not only imparts a stable red hue to the product (with a^* values maintaining between 30.29 and 33.86 and chroma values ranged from 25.42 to 37.43), enhancing the realism of PBMA, but also significantly influences its thermal stability and surface hydrophobicity by regulating the conformation rearrangement and aggregation behavior of the proteins. Specifically, SPI-MP and PPI-MP exhibited denser, more ordered structures, with enhanced thermal stability (ΔTp = 16.17°C and 2.88°C, respectively). In contrast, the thermal stability of the SPC-MP decreased (ΔTp = -6.86°C). Surface hydrophobicity results showed that SPI-MP and SPC-MP increased by 17.3% and 45.42%, respectively, while PPI-MP decreased by 4.67%. MP-protein complexes mainly through hydrogen bonding and hydrophobic interactions, influencing protein folding and structural stability. These findings reveal the regulatory mechanisms of MP on protein structure and functionality during extrusion, providing theoretical and practical guidance for optimizing the appearance and texture of PBMA. PRACTICAL APPLICATIONS: This study offers perspectives on the molecular processes by which the MP controls protein structuring during extrusion by forming hydrogen bonds and hydrophobic interactions. These results are useful for creating plant-based meat analogs with better texture and color stability. This study addresses consumer expectations in the expanding alternative protein industry by clarifying how MP affects various protein matrices and providing a theoretical basis for customizing plant-based meat formulations to improve both visual appeal and structural integrity.