title: Enhancement of wheat grain antioxidant activity by solid state fermentation with Grifola spp.
abstract: Grifola frondosa, Grifola gargal, and Grifola sordulenta are edible and medicinal mushrooms with antioxidant properties. To obtain wheat flour (Wf ) with a higher antioxidant activity than the one exhibited by regular Wf, solid state fermentation (SSF) of wheat grains with mycelia of those Grifola spp. was used to obtain biotransformed wheat grain (BWG) flour. The methanolic extract of control Wf and BWG flour of G. gargal, G. sordulenta, and G. frondosa (GfWG, GgWG, and GsWG, respectively) were studied for their radical scavenging (RS) activity against 2,2-diphenyl-1-picrylhydracyl (DPPH) and their Fe(III) reducing power (RP). The values for RS-EC50 decreased in BWG flour, therefore presenting a higher antioxidant activity: GgWG (0.56 mg/mL), GfWG (0.81 mg/mL), and GsWG (5.80 mg/mL) in comparison to Wf (57.60 mg/mL). The antioxidant content for this RS activity in terms of ascorbic acid content (RS-EQAA) was highest in GfWG, followed by GgWG and GsWG (71.73, 14.46, and 3.02 mg/g, respectively) and lowest in Wf (0.25 mg/g). The RP-EC50 values in GgWG, GfWG, and GsWG were low (0.55, 0.64, and 4.20 mg/mL, respectively) with respect to Wf (55.00 mg/mL). Compared with Wf (0.56 mg/g), the RP capacity in terms of ascorbic acid content (RP-EQAA) was very high in GfWG (193.67 mg/g) followed by GgWG and GsWG (31.42 and 8.74 mg/g, respectively). The high content in gallic acid equivalents was consistent with RS-EQ(AA) and RP-EQ(AA) contents. TLC revealed that antioxidant activity in BWG could be related to the presence of phenolic compounds. Thus, a valuable food alternative can easily be obtained with wheat grains, that is, by markedly increasing their antioxidant value through SSF with Grifola spp.
authors.affiliation: Laboratory of Biotechnology of Edible and Medicinal Mushrooms , Center for Renewable Natural Resources of the Semiarid Region (CERZOS), National Scientific and Technical Research Council (CONICET) and National University of the South (UNS), Bahía Blanca, Argentina .
authors.forename: Pablo
authors.initials: P
authors.lastname: Postemsky
authors.forename: Néstor
authors.initials: N
authors.lastname: Curvetto
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000032:analysis; D005285:Fermentation; D005433:Flour; D016166:Free Radical Scavengers / Q000494:pharmacology; D005707:Gallic Acid / Q000032:analysis; D048691:Grifola / Q000378:metabolism*; D000432:Methanol; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry* / Q000378:metabolism; D014908:Triticum / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D005707:Gallic Acid; D001205:Ascorbic Acid; D000432:Methanol
keywords: DPPH-radical scavenging activity; Grifola frondosa; Grifola gargal; Grifola sordulenta; functional food; phenols; radical scavenging; reducing power; solid state fermentation; wheat grains