Soluble Antioxidant Compounds Regenerate the Antioxidants Bound to Insoluble Parts of Foods

Abstract

This study aimed to investigate the regeneration potential of antioxidant capacity of an insoluble food matrix. Investigations were performed in vitro with several food matrices rich in dietary fiber (DF) and bound antioxidants. After removal of the soluble fraction, the antioxidant capacity (AC) of the insoluble fraction was measured by the QUENCHER procedure using ABTS(•+) or DPPH(•) radicals. After measurement, the insoluble residue was washed out to remove the excess of radicals and treated with pure antioxidant solution or antioxidant-rich beverage to regenerate depleted antioxidants on the fiber. Results revealed that the antioxidant capacity of compounds chemically bound to the insoluble moiety could be reconstituted in the presence of other hydrogen-donating substances in the liquid phase. Regeneration efficiency was found to range between 21.5 and 154.3% depending on the type of insoluble food matrix and regeneration agent. Among the food matrices studied, cereal products were found to have slightly higher regeneration efficiency, whereas antioxidant-rich beverages were more effective than pure antioxidants as regeneration agents. Taking wheat bran as reference insoluble material, the regeneration abilities of beverages were in the following order: green tea > espresso coffee > black tea > instant coffee > orange juice > red wine. These results highlighted the possible physiological relevance of antioxidants bound to the insoluble food material in the gastrointestinal tract. During the digestion process they could react with the free radicals and at the same time they can be regenerated by other soluble antioxidant compounds present in the meal.

The mechanism about the resistant dextrin improving sensorial quality of rice wine and red wine

“…All nonabsorbable metabolites and nonfermented polyphenols remain in the colonic lumen and contribute to the creation of a healthy antioxidant environment by scavenging free radicals and counteracting the effects of dietary pro‐oxidants. These results also support our findings (Celik, Gokmen, & Fogliano, ).…”

Antioxidants Bound to an Insoluble Food Matrix: Their Analysis, Regeneration Behavior, and Physiological Importance

“…These studies focus on the regeneration of soluble antioxidants, while the bound antioxidants are excluded. By contrast, in a study conducted by our research group, it was shown that the insoluble antioxidants bound to dietary fiber may be regenerated by soluble antioxidants (Çelik and others ). It was revealed that the antioxidant activity of antioxidants bound to dietary fiber can be reconstituted by other hydrogen‐donating substances (such as soluble antioxidant compounds) in the liquid phase.…”

“…It was revealed that the antioxidant activity of antioxidants bound to dietary fiber can be reconstituted by other hydrogen‐donating substances (such as soluble antioxidant compounds) in the liquid phase. According to the proposed mechanism, while bound antioxidant compounds come into contact with the radicals and transform into an antioxidant radical, the synergistic antioxidants in the liquid phase rapidly regenerated the bound antioxidants by providing electrons or hydrogen atoms (Çelik and others ). In line with this study, it was demonstrated that green tea catechins, as very effective regenerating agents, can interact with bound radicals found in dietary fiber and rapidly regenerate them.…”

Phytochemical composition and antiproliferative activities of bran fraction of ten Maryland-grown soft winter wheat cultivars: Comparison of different radical scavenging assays

“…Moreover, the wide variations in the reported antioxidant capacity values of these compounds stems from the differences in procedures used for the assay of antioxidants and the methodologies used for extraction of antioxidants (Luthria, 2006). Recently, researchers have developed a new procedure to measure the antioxidant capacities of insoluble bound phenolic acids in foods and cereal grains (Celik et al, 2013;Gokmen et al, 2009;Serpen et al, 2008;Tufan et al, 2013). Apak et al (2007) utilized the QUENCHER-CUPRAC method for assaying total antioxidant capacity, whereas Serpen et al (2007) measured antioxidant capacity in the insoluble portion of the food by QUENCHER procedure using ABTS + or DPPH .…”