Spatial Distribution of Antioxidant Activity in Baguette and Its Modulation of Proinflammatory Cytokines in RAW264.7 Macrophages

Abstract

Baguette, a globally acclaimed bakery staple, undergoes a complex Maillard reaction during the baking process, imparting a dual composition of crispy crust and soft crumb. Maillard reaction contributes to the unique flavor and texture of baguettes. However, its specific impact on the nutritional and health attributes, particularly in terms of cellular and biological functions, are yet to be clearly elucidated. This study investigates the chemical profiles of Maillard reaction products (MRPs) in baguette crust and crumb, and spatial distribution variations in the antioxidant activity. The impacts of baguette crust and crumb on cellular reactive oxygen species, mitochondrial activity, and inflammatory factors in RAW264.7 macrophages are also determined, aiming to elucidate the influence of the Maillard reaction on baguette nutritional efficacy. From the inside out, both the browning intensity and advanced glycation end products (AGEs) gradually increased, accompanied by a significant elevation in the antioxidant capacity of the crust (tested using ORAC/ABTS/FRAP). This suggests that the Maillard reaction enhances antioxidative properties. Additionally, both the crust and crumb exhibited a strong cytocompatibility for immune cells with capable of reversing cellular oxidative stress, regulating intracellular free radical levels. The crust mitigated the peroxyl radical induced cell membrane hyperpolarization by 91% and the suppression on the oxygen respiration in mitochondria by up to 100%, showing higher activities than the crumb. Conversely, the crumb more effectively inhibited the lipopolysaccharide (LPS)-induced proinflammatory cytokines expression of interleukin-1β (IL-1β) and interleukin-6 (IL-6) in macrophages. It could provide the fundamental data and cell-based approach for investigating the biological impacts of bread on mucosal immune responses, contributing to the refinement and supplementation of nutritional recommendations.