Phenolic Compounds in Wheat Grain Cultivars

Three hydroxybenzoic acids: p-hydroxybenzoic acid, vanillic acid and syringic acid; six hydroxycinnamic acids: p-coumaric acid, ferulic acid and four ferulic acid derivatives and a flavonoid (apigenin) were identified and quantified in 34 accessions corresponding to 19 cultivars of wheat applying HPLC coupled to diode array detector. Considerable differences between the wheat cultivars were observed in the phenolic contents. Some cultivars (Colorado, Del País, Barbilla, Jallado, Raspinegro Canario and Plaganudo) could be selected according to the high levels of phenolic compounds. Ferulic acid was the major phenolic acid compound followed by syringic and p-hydroxybenzoic acids. The proportion of ferulic acid present as dimeric forms ranged from 4.2 to 8.6% across all of the wheat cultivars analyzed. Apigenin, p-hydroxybenzoic and syringic acids did not show significant correlations. Many correlations between the determined hydroxycinnamic acids were observed. The ferulic acid and all the ferulic acid derivatives showed highly significant correlations, suggesting that the concentrations of diferulic acids depend on the concentration of ferulic acid.     

Anthocyanins,Phenolic Acids and Antioxidant Properties of Juçara Fruits (Euterpe edulis M.) Along the On-tree Ripening Process

Juçara (Euterpe edulis M.) fruits are an interesting source of phenolic compounds, mainly anthocyanins, making them valuable to the food and pharmaceutical industries. Juçara fruits were harvested along the on-tree ripening process between March and June as practiced in Paraná state, Brazil and examined for their total anthocyanin content (TAC), total phenolic content (TPC), total phenolic acid (TPA) and total antioxidant capacity (TAA). Overall, TAC increased (91.52–236.19 mg cyanidin-3-glucoside equivalent/100 g dm) whereas TPC (81.69–49.09 mg GAE/g dm) and TPA (44.27–30.95 mg/100 g dm) decreased during ripening of juçara fruits. Use of tandem mass spectrometry allowed the identification of cyanidin-3,5-diglucoside, peonidin-3-glucoside and peonidin-3-rutinoside for the first time in juçara fruits. The analysis of the phenolic acids by HPLC-MS/MS indicated the presence of gallic, protocatechuic, p-hydroxybenzoic, vanillic, chlorogenic, caffeic, syringic, p-coumaric, sinapinic and ferulic acids. The high antioxidant capacity using DPPH radical scavenging capacity (655.89–745.32 μmol TE/g dm) and ORAC assays (1088.10–2071.55 μmol TE/g dm) showed that juçara fruits have potential as a source of novel natural antioxidants for disease prevention and health promotion, and also as natural food additives for developing new functional food products.     

Physicochemical assessment and bioactive properties of condensed distillers solubles,a by-product from the sorghum bio-fuel industry

Large volumes of condensed distillers solubles (CDS) are generated as by-products, from the sorghum bioethanol industry. The objective was to assess the physico-chemical and bioactive properties of CDS. The unfractionated CDS showed the highest content of phenolic compounds (16 mg GAE/g), antioxidant (522 μM Trolox/g) and antimicrobial activity (MIC 1%(w/v) against Campylobacter spp.) compared to its extracts. The water and methanol extracts also showed high levels of phenolic compounds and antioxidant activity (11.6 and 9.2 mg GAE/g and 349 and 409 μM Trolox/g respectively), followed by ethanol and acetone extractions (7.5 and 6.6 mg GAE/g; 337 and 346 μM Trolox/g respectively). A positive correlation was revealed between total phenol and antioxidant activity. The main phenolic compounds found in the extracts were protocatechuic acid, 4-hydroxybenzoic acid, taxifolin, ferulic acid, cinnamic acid and p-coumaric acid. This study indicates the potential of using CDS as a functional ingredient for other food and feed applications.     

Phenolic acids composition,total polyphenols content and antioxidant activity of Triticum monococcum, Triticum turgidum and Triticum aestivum: A two-years evaluation

Wheat is a good source of polyphenols, plant metabolytes with beneficial effects on human health. However, little information is available on phenolic acid composition and concentration in different Triticum species, as well as on possible environmental effects. To shed some light on this issue, thirty-nine wheat accessions cropped for two years and belonging to different Triticum species (Triticum monococcum, Triticum turgidum ssp. dicoccum, turanicum and durum, Triticum aestivum ssp. spelta and aestivum) were assessed for phenolic acids (ferulic, p-coumaric, vanillic, syringic, p-hydroxybenzoic, caffeic acids and syringaldehyde), total polyphenols and antioxidant activity in soluble conjugated and insoluble bound extracts. Ferulic acid was the most abundant compound in both extracts. Insoluble bound phenolic acids represented >90% of total phenolic acids. Einkorn showed the maximum concentration of conjugated phenolic acids (50.5 mg/kg DM), while durum and bread wheats presented the highest content of bound phenolic acids (651.8 and 629.2 mg/kg DM, respectively). Cropping year influenced the concentration of conjugated but not of bound phenolic acids. A survey of phenolic acid distribution in the kernel showed that they are rare in endosperm, but abundant in germ and bran. Total polyphenols and antioxidant activity were highly correlated to phenolic acid content.     

Phenolic Compounds as Cultivar- and Variety-distinguishing Factors in Some Plant Products

The aim of the study was to determine whether phenolic compounds in some varieties of buckwheat, winter and spring barley and peas can be used as factors which distinguish selected cultivars and varieties of plant material. It was observed that the content of total phenolics might be useful as a cultivar-distinguishing factor for all the plant materials analyzed, but it was a distinguishing factor for only some varieties. Individual cultivars and varieties were best distinguished by the content of syringic acid. The levels of syringic and vanillic acids were in reverse proportion to the total amount of phenolics soluble in methanol and a positive correlation between syringic and ferulic acid was observed. Moreover, the protein content of plant material was analyzed and a significant (p ≤ 0.05) correlation between this component and ferulic and vanillic acids was noted.     

Influence of sprouting and elicitation on phenolic acids profile and antioxidant activity of wheat seedlings

Influence of germination and elicitation on nutraceutical potential of sprouted wheat was investigated. The seeds of three Polish winter wheat cultivars were elicited with 0.1% (w/v) of Saccacharomyces cerevisiae (SC) extract, 0.1% (v/v) Salix daphnoides (SD) bark extract and their combinations (SC/SD 1:1). Seeds were germinated for 4 day at 20 °C in darkness. For phenolic acids determination LC-ESI-MS/MS analysis was used. Antiradical ability, chelating power, reducing power and ability to prevent lipids against oxidation were determined. Bioaccessibility of antioxidative compounds was estimated using in vitro digestion method. Eleven phenolic acids (protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syryngic, p-coumaric, cis- and trans-ferulic, salicylic, trans- and cis-synapinic) were identified. Sprouting increased p-hydroxybenzoic, syryngic and p-coumaric acids level. The most effective elicitor for improving antioxidant activity of potentially bioaccessible phytochemicals was SD. Especially high effect was obtained for antiradical activity, chelating power and ability to lipid prevention.     

Variation in Oat Groats Due to Variety, Storage and Heat Treatment. I: Phenolic Compounds

Low molecular weight phenolic compounds present in heat processed oats (Avena sativaL) were analysed. The oat grains were of three varieties (Kapp, Mustang and Svea), stored at different relative humidities (30, 55 or 80%) and periods (3·5 or 15·5 months) and processed with or without hulls. Eleven UV-absorbing compounds detected by High Performance Liquid Chromatography were subjected to univariate and multivariate statistical analysis. The selected compounds included caffeic acid,p-coumaric acid, ferulic acid, vanillic acid,p-hydroxybenzaldehyde, vanillin, coniferyl alcohol, three avenanthramides and one unidentified substance. The levels of vanillic acid, vanillin and, especially,p-coumaric acid,p-hydroxybenzaldehyde and coniferyl alcohol increased significantly in samples processed with hulls, but not in samples processed without hulls. Ferulic acid increased in both processes, while caffeic acid and the avenanthramides were found to decrease during processing. Storage of unprocessed samples for 1 year generally increased the levels of phenolic acids and aldehydes. For the phenolic acids (except ferulic acid), this increase was most pronounced after storage at high relative humidity (80%). The avenanthramides were present at their highest levels in Mustang, caffeic acid in Svea and Mustang, the unidentified compound in Svea, while all the other compounds studied were present predominantly in the variety Kapp.     

The Phenolic Contents and Antioxidant Activities of Infusions of <Emphasis Type="Italic">Sambucus nigra</Emphasis> L.

The aim of this work was to evaluate the antioxidant potential of teas prepared from twenty-four commercially available berries and flowers of Sambucus nigra L. in relation to their phenolic profile, as reflected by the most representative phenolic acids (caffeic, chlorogenic, p-coumaric, ferulic, gallic and syringic acids); flavonols (quercetin, kaempferol, myricetin and rutin); and total phenolic (TPC), phenolic acid (TAC) and flavonoid (TFC) contents. The infusions prepared from elderflowers contained more abundant phenolic compounds than the elderberry infusions. The TPC of these infusions ranged from 19.81 to 23.90 mg of gallic acid equivalents/g dry weight of sample (GAE/g DW) for elderberries and from 15.23 to 35.57 mg GAE/g DW for elderflowers, whereas the TFC ranged from 2.60 to 4.49 mg of rutin equivalents/g dry weight of sample (RUTE/g DW) in elderberry infusions and from 5.27 to 13.19 mg RUTE/g DW in elderflower infusions. Among the phenolic compounds quantified in this study, quercetin (2.07–9.48 mg/g DW) and myricetin (1.17–9.62 mg/g DW) had the highest concentrations in the teas prepared from berries and flowers, respectively. Moreover, the antioxidant potential of elder infusions assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ferric reducing antioxidant power (FRAP) assays revealed that the teas prepared from flowers had higher mean DPPH and FRAP activities than the teas prepared from berries. Therefore, elder beverages could be important dietary sources of natural antioxidants that contribute to the prevention of diseases caused by oxidative stress.     

Phenolic compounds in raw and cooked rice (Oryza sativa L.) and their inhibitory effect on the activity of angiotensin I-converting enzyme

Whole rice has been widely studied due to the abundance of bioactive compounds in its pericarp. Some of the beneficial effects of these compounds on human health have been attributed to their antioxidant and other biological activities, such as enzyme inhibition. In this work, we evaluated the contents of total, soluble and insoluble phenolic compounds of 6 red and 10 non-pigmented genotypes of whole rice as well as their inhibitory effect on the activity of angiotensin I-converting enzyme (ACE). The effects of cooking on phenolics and their inhibitory activities were also investigated. Red genotypes showed high content of phenolics, mainly soluble compounds, at an average of 409.7 mg ferulic acid eq./100 g, whereas overall lower average levels (99.4 mg ferulic acid eq./100 g) at an approximate soluble/insoluble compound ratio of 1:1 were observed in non-pigmented rice. Pigmented rice displayed a greater inhibitory effect on ACE than non-pigmented rice. In fact, a significant correlation between the content of soluble phenolics and ACE inhibition was observed (r = 0.8985, p < 0.05). In addition to significantly reducing the levels of total phenolics and ACE inhibition, cooking altered the soluble/insoluble compound ratio, especially among red rice genotypes.     

Change in Colour and Antioxidant Content of Tomato Cultivars Following Forced-Air Drying

Three New Zealand grown tomato (Lycopersicon esculentum L.) cultivars, Aranka, Encore, and Flavourine, were analysed for colour (CIELAB L^∗ a^∗ b^∗ values), ascorbic acid, total phenolics, lycopene, and total antioxidant activity (ABTS assay). Colour analyses of the air-dried tomatoes showed that the colour degradation as measured by the L^∗ a^∗ b^∗ values was minimal, and the colour was not significantly different (p < 0.05) between each of the dried cultivars. In general, there was no significant difference (p < 0.01) between the fresh cultivars in terms of antioxidant components or total antioxidant activity. The average values obtained for antioxidant components in the three fresh cultivars were: ascorbic acid, 276 mg/100 g DM, total phenolics, 613 mg gallic acid equivalents (GAE)/100 g dry matter (DM) and lycopene 38 mg/100 g DM. Total antioxidant activity of the fresh cultivars was 2917 μmole Trolox equivalent antioxidant capacity (TEAC)/100 g DM. Following forced air-drying treatment at 42 ^∘C for 48 hr, all cultivars showed significant decreases in ascorbic acid, total phenolics and total antioxidant activity, and increases in extractable lycopene contents. This study was undertaken to identify cultivars that would provide the best colour and nutrient contents after commercial air drying.     

Phenolic acid profiles of Chinese wheat cultivars

Phenolic acid concentrations were determined in 37 Chinese commercial winter wheat cultivars grown at a single site over two seasons, and fractions comprising free and bound types were analyzed using HPLC with measurements of individual phenolic acids in each fraction. Most of the parameters were significantly influenced by cultivar, season, and their interaction effects, with cultivar variance being predominant. Wide ranges of concentration among the 37 cultivars were observed. The average concentration of bound type was 661 μg g⁻¹ of dm, making up 97.5% of the phenolic acid determined with ferulic accounting for 70.7% of it, while free type made up only 2.5% of the phenolic acid determined with syringic accounting for 44.7% of it. Bound type was the predominant source to the grain phenolic acid concentrations determined. There were highly significant and positive correlations between bound ferulic concentration and total bound phenolic acid concentration, and between free syringic concentration and total free phenolic acid concentration. Cultivars Liangxing 66 and Zhongmai 895 were stable in concentration of components of phenolic acids across seasons, with high values of free and bound phenolic acids indicating they could be selected as parents in wheat breeding for health beneficial phenolic acid.     

Phenolics in the bran of waxy wheat and triticale lines

The present study was designed to determine total phenolic acid contents (TPC) and compositions of bran from newly developed near-isogenic waxy wheat and triticale translocation lines. Two waxy wheat sets, Svevo (durum) and N11 (bread wheat), consisting of partial and waxy null lines and four sets of triticales (GDS7, Trim, Rhino and Rigel) having translocations at 1A.1D and 1R.1D with high molecular weight glutenin subunits (HMW-GS) 5 + 10 and 2 + 12 were investigated. Similar to non-waxy wheat, ferulic acid was the predominant phenolic acid found in waxy wheats analyzed. Two other major phenolics include p-coumaric and vanillic acids followed by lesser quantities of syringic acid. Waxy lines had higher TPC than the parent line in the N11 set, whereas the Svevo set showed the opposite trend. TPC of waxy bread wheats were correlated with amylose fractions in which the order was complete waxy < double waxy nulls < single waxy nulls. Lines with HMW-GS 2 + 12 have lower TPC than other lines in each group of triticales, except the Trim set. TPC was negatively correlated (r = −0.41; p > 0.1) with bran yields in triticale lines studied, indicating that variation in phenolics was not only due to bran yields but also to genotypic differences.     

Biochemical Properties of Red Currant Varieties in Relation to Storage

Eleven red currant varieties (Ribes rubrum L.) cultured in Serbia were evaluated for some of their biochemical properties such as total phenolics, anthocyanins, ascorbic acid, invert sugar, soluble solid content, and acidity. The average amount of ascorbic acid varied from 50.5–71.6 mg/100 g FW, while concentration of invert sugars ranged from 6.0%–9.0%. The highest amounts of total phenolics and anthocyanins were detected in variety Redpoll (153.4 mg GAE/100 g FW and 19.3 mg/100 g, respectively). Red currants were processed to juice, and the phenolic and anthocyanin contents changed as a result of processing. Berries and juices were long-term stored at −18 °C and changes in phytochemicals were monitored. In berries, storage caused the decrease of ascorbic acid content up to 49%, and a general reduction of total phenolics was also noticed. In juices, total phenolics content increased after one year of storage. In both berries and juices total anthocyanins increased during storage by up to 85% and 50%, respectively. This study demonstrates that certain varieties, namely Redpoll, Jonkheer and London Market are good source of phytochemicals, retaining the nutritional value during processing and storage.     

Phenolic acid profiles of Chinese wheat cultivars

Phenolic acid concentrations were determined in 37 Chinese commercial winter wheat cultivars grown at a single site over two seasons, and fractions comprising free and bound types were analyzed using HPLC with measurements of individual phenolic acids in each fraction. Most of the parameters were significantly influenced by cultivar, season, and their interaction effects, with cultivar variance being predominant. Wide ranges of concentration among the 37 cultivars were observed. The average concentration of bound type was 661 μg g⁻¹ of dm, making up 97.5% of the phenolic acid determined with ferulic accounting for 70.7% of it, while free type made up only 2.5% of the phenolic acid determined with syringic accounting for 44.7% of it. Bound type was the predominant source to the grain phenolic acid concentrations determined. There were highly significant and positive correlations between bound ferulic concentration and total bound phenolic acid concentration, and between free syringic concentration and total free phenolic acid concentration. Cultivars Liangxing 66 and Zhongmai 895 were stable in concentration of components of phenolic acids across seasons, with high values of free and bound phenolic acids indicating they could be selected as parents in wheat breeding for health beneficial phenolic acid.     

Determination of phenolic acid concentrations in wheat flours produced at different extraction rates

High-performance liquid chromatography (HPLC) was used to determine the distribution of phenolic acids in wheat flours produced from five milling extraction rates ranging from 60% to 100% in four cultivars sown in two locations in the 2008–2009 season. Considerable variation was observed in free and bound phenolic acids, and their components in flours with different extraction rates. Most phenolic acids, including the component ferulic, were present in the bound form (94.0%). Ferulic (51.0%) was the predominant phenolic acid in wheat grain, and caffeic (22.8%) and p-coumaric (17.6%) acids were abundant. The phenolic acids and their components were all significantly influenced by effects of cultivar, milling, location, and cultivar × milling interaction, with milling effect being the predominant. The proportions of phenolic compounds varied considerably among milling extractions and cultivars, and their levels depended on both initial grain concentrations and on selection of milling extraction that was incorporated into the final product. The grain phenolic acid concentrations determined ranged from 54 μg g⁻¹ in flour produced at 60% extraction rate to 695 μg g⁻¹ in flour produced at 100% extraction rate, indicating their higher concentrations in bran associated with cell wall materials. Therefore, wholemeal wheat products maximize health benefits and are strongly recommended for use in food processing.     

Isolation and antioxidative properties of phenolics-saponins rich fraction from defatted rice bran

The study presents a protocol for the preparation of phenolics-saponins rich fraction (PSRF), a new active nutraceutical from defatted rice bran followed by the determination of its antioxidant properties. PSRF was prepared by employing a simple alcoholic fractionation procedure on the crude alcoholic extract (CAE) of defatted rice bran. PSRF was found to be significantly higher in the contents of total phenolic, saponin, and steroidal saponin than CAE and its counterpart, aqueous fraction (AqF) (p < 0.05). Except for iron chelating activity, PSRF exhibited notably higher activity than CAE and AqF in all antioxidant activity assays performed (p < 0.05). HPLC-DAD analysis revealed that PSRF contained substantially higher amounts of gallic acid, 4-hydroxybenzoic acid, caffeic acid, p-coumaric acid, and ferulic acid than CAE and AqF (p < 0.05). In conclusion, alcoholic fractionation of CAE simultaneously concentrated the phenolic compounds and saponins into PSRF, thus contributed to its higher antioxidant activity. Due to its elevated antioxidant properties, PSRF may be recommended for investigation as an active ingredient in the nutraceutical, functional food, and natural food preservative formulations. This is also the first report suggesting defatted rice bran as a potential and sustainable source of saponins.     

Antioxidant in Mango (<Emphasis Type="Italic">Mangifera indica</Emphasis> L.) Pulp

This work was carried out to investigate the pulp composition of four mango cultivars (Haden, Tommy Atkins and Ubá) at the ripening stage in relation to three components with antioxidant potential (total phenolics, carotenoids and ascorbic acid). Total phenolic compound content was estimated by the Folin-Ciocalteu reagent and total carotenoid content by spectrophotometry at 450 nm. The contents of β-carotene and total vitamin C (ascorbic acid and dehydroascorbic acid) were quantified by high performance liquid chromatography. Differences were found among the four mango cultivars in all the components analyzed. The content of phenolic compounds ranged from 48.40 (Haden) to 208.70 mg/100 g (Ubá); total carotenoid from 1.91 (Haden) to 2.63 mg/100 g (Palmer); β-carotene from 661.27 (Palmer) to 2,220 μg/100 g (Ubá) and total ascorbic acid ranged from 9.79 (Tommy Atkins) to 77.71 mg/100 g (Ubá). These results corroborated previous information that mangoes are a good source of antioxidants in human diet.     

Comprehensive Analysis of Polyphenols in 55 Extra Virgin Olive Oils by HPLC-ECD and Their Correlation with Antioxidant Activities

In this study, we analyzed eight phenolic compounds (tyrosol, hydroxytyrosol, oleuropein, pinoresinol, and caffeic, ferulic, vanillic, and p-coumaric acid) in 55 mono- and multivarietal extra virgin olive oil samples by high performance liquid chromatography (HPLC) coupled to a coulometric electrochemical array detector (ECD). The phenolic profile of olive oil samples differed depending on the geographical origin and olive variety. The total reducing capacity (total phenolics) of olive oils ranged from about 40 to 530 mg gallic acid equivalents/kg oil. Tyrosol, hydroxytyrosol and pinoresinol were the most abundant phenolic compounds in olive oils. The antioxidant capacity of the olive oil extracts was determined by ferric reducing antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assays. Total reducing capacity was significatly correlated with FRAP (R ² ?=?0.91, p?<?0.001) and TEAC (R ² ?=?0.92, p?<?0.001) values. Total reducing capacity, TEAC and FRAP values were significantly correlated with tyrosol, hydroxytyrosol as well as oleuropein concentrations. Hydroxytyrosol, comprising over 40 % of total olive oil phenolics, mainly contributed to the antioxidant activity of olive oils. The present study provides a comprehensive database of polyphenols in olive oils from 9 different countries and four continents.     

Identification and quantification of phenolic acids and anthocyanins as antioxidants in bran,embryo and endosperm of white,red and black rice kernels (Oryza sativa L.)

Whole rice grain comprising endosperm, embryo (or germ), and bran has potential beneficial health effects in addition to provision of nutrients. The distribution of phenolic acids and anthocyanins in endosperm, embryo, and bran of white, red, and black rice grains was investigated in this study. The total phenolic content (TPC) was highest in the bran, averaging 7.35 mg GAE/g and contributing 60%, 86% and 84% of phenolics in white, red and black rice. The average TPC of the embryo and endosperm were 2.79 and 0.11 mg GAE/g accounting for 17% and 23%, 4% and 10% and 7% and 9% in white, red and black rice, respectively. The antioxidant capacity determined using DPPH and ORAC displayed a trend similar to TPC. Free/conjugated phenolic acids in white, red and black rice bran accounted for 41%, 65% and 85% of total acids. Bound phenolic acids in rice bran accounted for 90% of total acids in whole grain. Cis-p-coumaric was detected in bound form in bran while cis-sinapic acid was detected in the free/conjugated form in embryo and bran. Cyanidin-3-O-glucoside and peonidin-3-O-glucoside were identified mainly in black rice bran as the total anthocyanins. Cyanindin-3-O-rutinoside was also detected in black rice bran.     

Effect of genetic variation on phenolic acid and policosanol contents of Pegaso wheat lines

Total phenolic acid and policosanol contents and compositions of bran from an Italian bread wheat variety Pegaso and its 11 near-isogenic lines were measured. The near-isogenic wheat lines differed at one or more loci coding for storage proteins. The genetic variation included deletions, additions and/or combinations of variations. Almost 95% or more of phenolic acids were in the bound form. Ferulic acid was the predominant bound phenolic acid present in wheat bran samples. Other phenolic acids were p-coumaric, vanillic and syringic acids. Tetracosanol, docosanol, hexacosanol, octacosanol, tricosanol and heneicosanol were found as major policosanol compounds in their decreasing order. Highly significant genotypic differences were observed in total phenolic acid and policosanol concentrations. None of the genetic lines had higher phenolic acid contents than the parent line Pegaso, whereas some of the lines had more policosanol levels. In general, both total phenolic acid composition and contents were higher with genetic lines that varied at Glu-1 loci with 2+Dy high molecular weight glutenin subunit (HMW-GS) (Pegaso 184), variation at Gli-D2 loci (Pegaso 219) and single null A1 (variation at Gli-1/Glu-3 loci; Pegaso 30). Highest total policosanol content was observed with the double null at Glu-A1/Glu-D1 loci (Pegaso 236). These findings may lead to new opportunities for wheat breeders and eventually commercial wheat growers to promote the production of wheat with enhanced levels of health beneficial compounds.