Synthesis and characterization of functional Monascus yellow pigment-tannic acid complexes via Co-pigmentation

Natural Monascus yellow pigments (MYPs) have potential in the food industry due to their safety, but their application is limited by low biological activity and stability. Novel MYPs complexes, Monascus yellow pigments-tannic acid (MYPs-TA), were synthesized by spontaneously incorporating TA through intermolecular co-pigmentation in this work. Structural analysis revealed that multiple interactions contributed to the formation of complexes, including hydrogen bonding, π-π stacking, and hydrophobic interactions. The MYPs-TA exhibited characteristic ultraviolet signals of both MYPs (380 nm) and TA (276 nm), and the crystalline structure of MYPs transitioned to an amorphous form. These phenomena confirmed the tight combination of MYPs and TA. Color tonality, physicochemical stability as well as antimicrobial and antioxidant activities of MYPs were significantly improved after interaction with TA. Besides, MYPs-TA exhibited optimal stability and functionality in high-temperature processed foods such as baked goods or pasteurized products. This study provides a novel approach for synthesizing functional MYPs complexes with superior stability.