The effect of high hydrostatic pressure on anthocyanin stability via pectin interaction: A multifaceted study on thermal, digestive, and environmental stress in food systems

Although widely used as natural pigments in food products, anthocyanins face considerable limitations in food applications owing to their low stability during processing and storage and poor retention, particularly under alkaline intestinal conditions where >70 % degradation of anthocyanins occurs. While chemical or enzymatic stabilisation raises safety concerns, natural macromolecules such as pectin offer a safer alternative by stabilising anthocyanins through covalent and non-covalent interactions. This study aimed to investigate the effect of high hydrostatic pressure (HHP) on the anthocyanin–pectin complex and the protective effect of pomelo pectin on cyanidin-3-glucoside (C3G), to improve the stability of C3G under food processing–relevant thermal, digestive, light exposure, and metal-ion stress conditions. Pomelo pectin was extracted and complexed with C3G. The complexes, with or without HHP treatment (400 MPa, 15 min), were subjected to a multidimensional stabilisation test. HHP-treated complexes exhibited superior thermal stability. At 90 °C, their half-life (t1/2 = 2.92 h) exceeded that of free C3G (t1/2 = 2.21h), supported by thermogravimetric analysis and derived thermogravimetric analysis indicating reduced mass loss. During intestinal digestion, the HHP–pectin–C3G complex achieved 31.4 % retention, similar with untreated pectin–C3G complexes (30.1 %) and much higher than free C3G (23.9 %). Enhanced light stability was observed (61.1 % retention after 4 h of UV for HHP–pectin–C3G complex vs. 56.1 % for the untreated pectin–C3G control). Pectin complexes also conferred greater resistance to Cu2+-induced degradation. These findings demonstrate that pomelo pectin with or without HPP treatment could be used as a sustainable, food-grade matrix for stabilising anthocyanins in challenging food environments.