During fleshy fruit consumption and processing, metallic cations, cell wall pectin and vacuolar phenolic components come into contact. This mixing is at the origin of new interactions and reactions catalysed by reactive oxygen species arising from fruit metabolism or the presence of trace transition metal cations. Such oxidative reactions may induce cell wall deconstruction through pectin degradation or structural change of phenolic compounds. The consequences of this oxidative degradation will affect the organoleptic properties of the fruit and its product as well as its processability. To better understand these complex oxidative reactions, model solutions simplifying the fruit matrix rich in phenolic compounds such as found in apple and grape, were used to study the impact of (+)-catechin, p-coumaric acid, cyanidin, calcium, iron and hydrogen peroxide on pectin molecular weight. Results showed that H₂0₂ and Fe²⁺ are both required to depolymerize pectin. The antioxidant action of phenolic compounds limiting pectin degradation was shown to depend on iron concentration. At low iron concentration, (+)-catechin was revealed to act as a pro-oxidant. The results are discussed with regard to possible mechanisms involving the redox potential of iron and H₂O₂, and interactions between pectin, phenolic compounds and iron.

在食用和加工果肉的过程中，金属阳离子，细胞壁果胶和液泡酚类成分会接触。这种混合是由水果代谢或痕量过渡金属阳离子的存在引起的活性氧催化新的相互作用和反应的起点。这种氧化反应可通过果胶降解或酚类化合物的结构变化诱导细胞壁解构。这种氧化降解的后果将影响水果及其产品的感官特性以及可加工性。为了更好地理解这些复杂的氧化反应，模型的解决方案简化了水果矩阵丰富的，如苹果和葡萄中的酚类化合物，被用来研究（+）的影响-儿茶素，p-香豆酸，花青素，钙，铁和过氧化氢对果胶分子量的影响。结果表明，H ₂ 0 ₂和Fe ²⁺都需要使果胶解聚。限制果胶降解的酚类化合物的抗氧化作用显示取决于铁浓度。在低铁浓度下，（+）-儿茶素显示出可以作为促氧化剂。讨论了有关铁和H ₂ O ₂的氧化还原电位以及果胶，酚类化合物和铁之间相互作用的可能机理的结果。