Novel composite hydrogel encapsulating Monascus pigments with dual-function of color stability and off-flavor masking

As a natural pigment derived from fungi, Monascus pigments (MPs) was widely used in Asia. Its application is limited by poor color stability and distinct off-flavors. Here, a novel hydrogel named as HGP, composed by gelatin and pectin, was fabricated via dual cross-linking to encapsulate MPs to address these two shortcomings simultaneously. HGP showed the dense and interpenetrating microstructure confirmed by SEM, FT-IR, and TGA, with improved mechanical and hydration properties. Notably, the 8% HGP significantly improved color stability of MPs under thermal (100 °C, 7.5 h) and light (7000 lx, 6 days) stress. Volatile profiling by GC-TOF-MS identified 25 kinds of key odorous substances in MPs that were significantly reduced in 8-HGP-MPs. Sensory experiment demonstrated that 8-HGP significantly attenuated the characteristic fruity, fatty, musty, woody, alcoholic, and overall odor intensity of MPs. Correlation analysis further confirmed that the effective off-flavor masking of HGP-MPs was achieved by substantially lowering the concentrations of key volatiles of MPs. This work presents a food-grade dual-function carrier that overcomes the shortcomings of MPs, which expanded its use in food products.