Photostability and antimicrobial performance of natural yellow pigments in food systems: Insights into light-induced degradation and functional consequences

Natural yellow pigments such as bisdemethoxycurcumin (BDMC), curcumin (Cur), and geniposide are increasingly investigated as clean-label antimicrobial agents due to their reactive oxygen species (ROS)-mediated activity. However, their performance in food systems is often limited by photodegradation under visible light, particularly in refrigerated and transparent-packaged products. This review summarizes current understanding of the structure-dependent photochemical behavior, degradation pathways, and ROS-driven antibacterial mechanisms of representative yellow pigments. Evidence shows that extended π-conjugation and β-diketone structures enhance photo-reactivity but also accelerate photodegradation, leading to reduced antimicrobial efficacy. BDMC and Cur display strong ROS-mediated activity but limited light stability, whereas geniposide exhibits higher photostability but weaker intrinsic antibacterial activity. These findings highlight a trade-off between oxidative reactivity and light stability. Strategies such as light-shielding packaging and nanoencapsulation are discussed to improve pigment stability and antimicrobial performance in illuminated food systems. • Structure–photostability–function relationships of natural yellow pigments are clarified. • Curcumin, BDMC, and geniposide show distinct light stability profiles. • CIELAB color changes quantitatively indicate pigment degradation. • ROS generation and membrane disruption drive antibacterial activity. • Oxidative reactivity–light stability trade-off governs performance. • Encapsulation and light-filtering films improve pigment retention.