Comparison of Content in Phenolic Compounds and Antioxidant Capacity in Grains of White, Red, and Black Sorghum Varieties Grown in the Mediterranean Area

orghum (Sorghum bicolor L.) is a gluten-free cereal with many varieties containing greater amounts of bioactive compounds than other grains. In this work, the phenolic composition and antioxidant capacity were compared in three sorghum varieties grown in the Mediterranean, consisting of different pericarp colors: white, red, and black. The qualitative and quantitative profiles of acidified aqueous methanol extracts of whole grain sorghum flours were elucidated through ultrahigh performance liquid chromatography (UHPLC) coupled to photodiode array (PDA) and ion trap time-of-flight (IT-TOF) mass spectrometry. The investigated sorghum varieties contained polyamines, such as spermidines, and polyphenolic compounds belonging to different classes: hydroxycinnamic acids, flavanols, flavones, and flavanones. Pyrano-flavanone-flavanols were detected only in the black sorghum. Precolumn and postcolumn 2,2′-diphenyl-1-picrylhydrazyl (DPPH)· radical scavenging assays to determine the main antioxidant compounds isolated from sorghum were developed. These results will further help develop sorghum varieties containing polyphenols relevant to the potential prevention of human diseases

Comparison of extraction methods for isolating kafirin protein from food grade sorghum flour

Isolated sorghum (Sorghum bicolor) storage proteins (kafirins) have been successfully used in the production of several bio-materials including adhesives, films, micro-particles, fibers, and biological scaffold material. Comparatively little research has been conducted on the use of isolated kafirins in food products or to produce bioactive peptides via hydrolysis for nutritional uses. To support such research, the aim of this study was to compare existing methods for bulk isolation of sorghum kafirins with the goal of identifying a solvent with the least toxicity that maintained a high extraction rate from food grade sorghum flour. A secondary goal was to characterize the kafirin isolates produced from various extraction methods to provide some information on their potential use in food products to guide future research in this area. Five different extraction methods were compared including 1) aqueous ethanol containing NaOH and sodium metabisulfite, 2) glacial acetic acid, 3) aqueous ethanol with sodium metabisulfite, 4) aqueous ethanol at acidic pH, and 5) alkaline pH alone. The protein contents of the kafirin isolates obtained by the five methods ranged from 49.76% to 56.83%. Kafirin isolates were characterized using reversed phase (RP)-high performance liquid chromatography (HPLC), which revealed substantial variability in the various kafirin patterns among the extraction methods tested. However, characterization of the kafirin isolates by size exclusion chromatography (SEC) did not show a high degree of variability among the methods tested. Likewise, analysis of the samples using sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE) showed essentially the same band profiles but with different band intensities among kafirin extraction methods. Surface hydrophobicity of the kafirin isolates varied considerably with isolates extracted with glacial acetic acid and aqueous ethanol plus sodium metabisulfite the most hydrophobic as indicated by hydrophobic dye binding

Nutritional composition of a selected white food-grade waxy sorghum variety grown in Mediterranean environment

A white food-grade waxy sorghum Tw variety, grown in two Mediterranean sites (named Tw1M and Tw1S) was evaluated for nutrient composition and fatty acid- and mineral concentrations in order to determine the suitability of producing waxy sorghum for human uses in southern Italy. The nutritional values of the grains of the Tw inbred line grown in the two trial fields were substantially the same, except for slight differences in ash level and accordingly slight variation in mineral composition. In samples from both locations, a higher percentage of K was observed among the nutritionally essential macro-elements, and higher percentages of Zn, Fe, Mn, Cu, Al among the nutritionally essential micro-element along with a strong difference in Cd content was among trace elements. Across both sites linoleic, oleic and palmitic were the most abundant fatty acids, while very slight variations in the content of minerals were found among the two samples examined. These results demonstrate the importance of developing agronomically productive waxy sorghum varieties suitable for growth in non-traditional sorghum producing regions both as a food and feed crop (i.e. with good nutritional quality) and for utilization in new products at the industrial level

Chemical Composition, Fatty Acid and Mineral Content of Food-Grade White, Red and Black Sorghum Varieties Grown in the Mediterranean Environment

none15siGrain sorghum (Sorghum bicolor) is a gluten-free cereal grown around the world and is a food staple in semi-arid and subtropical regions. Sorghum is a diverse crop with a range of pericarp colour including white, various shades of red, and black, all of which show health-promoting properties as they are rich sources of antioxidants such as polyphenols, carotenoids, as well as micro- and macro-nutrients. This work examined the grain composition of three sorghum varieties possessing a range of pericarp colours (white, red, and black) grown in the Mediterranean region. To determine the nutritional quality independent of the contributions of phenolics, mineral and fatty acid content and composition were measured. Minor differences in both protein and carbohydrate were observed among varieties, and a higher fibre content was found in both the red and black varieties. A higher amount of total saturated fats was found in the white variety, while the black variety had a lower amount of total unsaturated and polyunsaturated fats than either the white or red varieties. Oleic, linoleic, and palmitic were the primary fatty acids in all three analysed sorghum varieties. Significant differences in mineral content were found among the samples with a greater amount of Mg, K, Al, Mn, Fe, Ni, Zn, Pb and U in both red and black than the white sorghum variety. The results show that sorghum whole grain flour made from grain with varying pericarp colours contains unique nutritional properties.Pontieri, Paola; Troisi, Jacopo; Calcagnile, Matteo; Bean, Scott R; Tilley, Michael; Aramouni, Fadi; Boffa, Antonio; Pepe, Giacomo; Campiglia, Pietro; Del Giudice, Fabio; Chessa, Alberto L; Smolensky, Dmitriy; Aletta, Mariarosaria; Alifano, Pietro; Del Giudice, LuigiPontieri, Paola; Troisi, Jacopo; Calcagnile, Matteo; Bean, Scott R; Tilley, Michael; Aramouni, Fadi; Boffa, Antonio; Pepe, Giacomo; Campiglia, Pietro; Del Giudice, Fabio; Chessa, Alberto L; Smolensky, Dmitriy; Aletta, Mariarosaria; Alifano, Pietro; Del Giudice, Luig