Non-enzymatic browning kinetics and browning factor path analysis of navel orange peel fillings under different...

Navel orange peel fillings are prone to non-enzymatic browning during processing and storage, yet the regulatory mechanism of exogenous conditions on this process remains unclear. This study established kinetic models and adopted path analysis to explore the effects of external factors on browning and its intrinsic drivers, aiming to provide theoretical and technical basis for scientific quality control of the fillings.

Key quality indexes (color difference, browning degree A ₄₂₀, total phenols, carotenoids, 5-hydroxymethylfurfural (5-HMF), ascorbic acid content) were monitored under different exogenous conditions (sterilization method, storage temperature, storage time and packaging material). Elevated temperature and prolonged storage increased a*, ΔE, A ₄₂₀ and 5-HMF, while decreasing L*, b*, total phenols, carotenoids and ascorbic acid. Path analysis identified 5-HMF accumulation as the dominant browning factor, proving the Maillard reaction as the main cause of non-enzymatic browning. Irradiation sterilization outperformed heat sterilization in retaining nutrients and reducing 5-HMF, and aluminium foil packaging better preserved filling color.

A valid kinetic model for predicting browning-related quality changes of the fillings was established, and path analysis clarified the core non-enzymatic browning mechanism (Maillard reaction driven by 5-HMF accumulation). Exogenous conditions significantly regulate browning, and the combined strategy of irradiation sterilization, aluminium foil packaging and 4 °C low-temperature storage is optimal for inhibiting browning and preserving the fillings' nutritional and color quality. © 2026 Society of Chemical Industry.