Ferulic Acid from Aleurone Determines the Antioxidant Potency of Wheat Grain (Triticum aestivum L.)

Abstract

Grain is an important source of phytochemicals, which have potent antioxidant capacity. They have been implicated in the beneficial health effect of whole grains in reducing cardiovascular disease and type 2 diabetes. The aim of the present study was to identify the most important antioxidant fractions of wheat grain. It was found that the aleurone content of these fractions was highly correlated with the antioxidant capacity of the fractions (r = 0.96, p < 0.0001). Ferulic acid appeared to be the major contributor to the antioxidant capacity in fractions with higher antioxidant capacity. The contribution of protein was rather limited. It was concluded that the antioxidant potency of wheat grain fractions is predominantly determined by aleurone content, which can be attributed to the presence of relatively large amounts of phenolic compounds, primarily ferulic acid.

Effect of processing and cooking on phenolic acid profile and antioxidant capacity of durum wheat pasta enriched with debranning fractions of wheat

“…Accordingly, the highest values in antioxidant capacity were found in the first fraction, where ferulic acid had the highest concentration (from 4 to 10-fold higher in respect to the other phenolic acids). Therefore, this study confirms that ferulic acid is responsible for potential antioxidant properties of wheat grain fractions (Adom, Sorrells, & Liu, 2005;Martinez-Tome et al, 2004;Mateo Anson et al, 2008;Zhou et al, 2004). Interestingly, the assessment of TPC by FolinCiocalteu method always showed values lower than the total content of phenolic acids up to fraction 2 (about 10% of debranning degree); subsequently up to fraction 4 the differences become slight and subsequently the values are increasingly high.…”

“…Zhou, Su, and Yu (2004) showed that the antioxidant properties of the outermost layers of wheat kernel are due to the presence of the aleurone layer. These antioxidant properties are attributed to the relative abundance of phenolic compounds, primarily ferulic acid, in the aleurone layer, with respect to the other bran tissues (Esposito et al, 2005;Mateo Anson, Van Der Berg, Havenaar, Bast, & Haenen, 2008;Rhodes, Sadek, & Stone, 2002;Zhou et al, 2004). Aleurone also contains most of the lignans (Buri, von Reding, & Gavin, 2004), which are polyphenols whose metabolites act as antioxidants, exhibit antitumoral activities and have been reported to modulate the effects of estrogens (Qu, Madl, Takemoto, Baybutt, & Wang, 2005).…”

“…Several authors have used these biochemical markers to determine the amounts of aleurone and pericarp in flours and other milling fractions (Greffeuille, Abecassis, Lapierre, & LullienPellerin, 2006;Hemery et al, 2009) and in samples obtained from the wheat bran fractionation process (Antoine et al, 2004). Accordingly, the presence of aleurone layer in wheat fractions was evidenced by its high phenolic acids content, primarily ferulic acid (Mateo Anson et al, 2008). Antoine et al (2004) have suggested that p-coumaric acid, which is known to be covalently bound to cell wall polysaccharides, could be considered a good indicator of the presence of aleurone cell walls.…”

The Bioavailability and Metabolism of Phenolics, a Class of Antioxidants Found in Grains

“…The aleurone and pericarp layers, which constitute the outer parts of the wheat grain, contain 98% of the total ferulic acid (38). Not surprisingly, the aleurone fraction of wheat has the highest antioxidant capacity, with ferulic acid contributing 60% of the antioxidant effect (41). Grain phenolics usually exist in free, soluble conjugate, and insoluble bound forms, and form has a huge effect on bioavailability.…”

“…Bioaccessibility refers to the portion of a compound that is released from the food matrix in the gastrointestinal lumen, making it available for intestinal absorption (50). Mateo Anson et al (42) examined the bioaccessibility of ferulic acid from different wheat fractions and breads using an in vitro system that simulates GI transit and digestion. They determined that <1% of ferulic acid bound to indigestible polysaccharides was bioaccessible; however, when free ferulic acid was added to flour, bioaccessibility increased to roughly 60%.…”