Phytochemical and fiber components in oat varieties in the HEALTHGRAIN Diversity Screen

The levels and compositions of a range of phytochemicals (sterols, tocols, avenanthramides, folates, phenolic acids) and dietary fiber components were determined in five oat cultivars (four husked and one naked) grown on a single site in 2005. The total levels of tocols, phenolic acids, and avenanthramides varied by over 2-fold between cultivars, but less variation occurred in total sterols and total folates. Limited variation was also observed in the dietary fiber content and composition of the four husked lines. These results indicate that it may be possible to selectively breed for lines with high contents of dietary fiber and specific groups of phytochemicals.     

Phytochemicals and dietary fiber components in rye varieties in the HEALTHGRAIN Diversity Screen

Ten rye varieties grown in one location were analyzed for their contents of dietary fiber (arabinoxylan and beta-glucan) and phytochemicals (folate, tocols, phenolic acids, alkylresorcinols, and sterols). The varieties included old and modern varieties from five European countries. Significant differences were observed in the contents of all phytochemicals in whole grains and in the fiber contents in the flour and bran. The old French varieties Haute Loire and Queyras had high contents of most phytochemicals, whereas the Polish varieties Dankowskie-Zlote and Warko were relatively poor in phytochemicals. The varieties with a high content of folate tended to have low alkylresorcinol contents and vice versa. Furthermore, high contents of arabinoxylans were associated with high contents in tocols and sterols. The 10 selected rye samples comprising old populations and old and modern varieties from different ecological regions of Europe demonstrate high natural variation in their composition and show that landraces and old populations are useful genetic resources for plant breeding. The contents of single phytochemicals can likely be affected by breeding, and they may be adjusted by the right selection of genotype.     

Variation in the content of dietary fiber and components thereof in wheats in the HEALTHGRAIN Diversity Screen

Within the HEALTHGRAIN diversity screening program, the variation in the content of dietary fiber and components thereof in different types of wheat was studied. The wheat types were winter (131 varieties) and spring (20 varieties) wheats (both Triticum aestivum L., also referred to as common wheats), durum wheat (Triticum durum Desf., 10 varieties), spelt wheat (Triticum spelta L., 5 varieties), einkorn wheat (T. monococcum L., 5 varieties), and emmer wheat (Triticum dicoccum Schubler, 5 varieties). Common wheats contained, on average, the highest level of dietary fiber [11.5-18.3% of dry matter (dm)], whereas einkorn and emmer wheats contained the lowest level (7.2-12.8% of dm). Intermediate levels were measured in durum and spelt wheats (10.7-15.5% of dm). Also, on the basis of the arabinoxylan levels in bran, the different wheat types could be divided this way, with ranges of 12.7-22.1% of dm for common wheats, 6.1-14.4% of dm for einkorn and emmer wheats, and 10.9-13.9% of dm for durum and spelt wheats. On average, bran arabinoxylan made up ca. 29% of the total dietary fiber content of wheat. In contrast to what was the case for bran, the arabinoxylan levels in flour were comparable between the different types of wheat. For wheat, in general, they varied between 1.35 and 2.75% of dm. Einkorn, emmer, and durum wheats contained about half the level of mixed-linkage beta-glucan (0.25-0.45% of dm) present in winter, spring, and spelt wheats (0.50-0.95% of dm). All wheat types had Klason lignin, the levels of which varied from 1.40 to 3.25% of dm. The arabinoxylan contents in bran and the dietary fiber contents in wholemeal were inversely and positively related with bran yield, respectively. Aqueous wholemeal extract viscosity, a measure for the level of soluble dietary fiber, was determined to large extent by the level of water-extractable arabinoxylan. In conclusion, the present study revealed substantial variation in the contents of dietary fiber and constituents thereof between different wheat types and varieties.     

Alkylresorcinols in wheat varieties in the HEALTHGRAIN Diversity Screen

The contents of alkylresorcinols (AR) were analyzed in 131 winter wheats, 20 spring wheats, 10 durum wheats, 5 spelt wheats, and 10 early cultivated forms of wheat (5 diploid einkorn and 5 tetraploid emmer), which are part of the HEALTHGRAIN diversity screen. AR were analyzed by gas chromatography (GC), which provides both total contents and relative homologue compositions, as well as with a Fast Blue colorimetric method that provides only total contents but which is fast and easily screens a large number of samples. There was considerable variation in the total AR content analyzed with GC: winter wheat (220-652 microg/g of dm), spring wheat (254-537 microg/g of dm), durum wheat (194-531 microg/g of dm), spelt (490-741 microg/g of dm), einkorn (545-654 microg/g of dm), and emmer wheat (531-714 microg/g of dm). The relative AR homologue composition was different for different types of wheat, with a C17:0 to C21:0 ratio of 0.1 for winter, spring, and spelt wheats, 0.04 for einkorn and emmer wheat, and 0.01 for durum wheat. The total AR content analyzed with the Fast Blue method was lower than that analyzed with GC but there was a good correlation between the two methods (R(2) = 0.76).     

Phenolic acids in wheat varieties in the HEALTHGRAIN Diversity Screen

The amounts and compositions of free, conjugated, bound, and total phenolic acids were determined in 175 samples of wheat flour grown on a single site in 2005. The highest contents of total phenolic acids were found in flours of winter wheat (1171 microg/g) with average levels of 658 microg/g total phenolics across all of the wheat genotypes. Winter wheats showed a range of >3.5-fold across the concentration range for total phenolic acids. Spelt genotypes displayed the narrowest (1.9-fold) range of total phenolic acid concentration. The concentrations of phenolic acids in the different phenolic acid fractions were in the order bound > conjugated > free, with bound phenolic acids making up around 77% of the total phenolic acid concentration and free phenolic acids constituting between 0.5 and 1%. The results indicate that there is genetic diversity in phenolic acid content and that it should be possible to selectively breed for lines with high contents of phenolic components.     

Tocopherols and tocotrienols in wheat genotypes in the HEALTHGRAIN Diversity Screen

Tocopherol and tocotrienol compositions were studied in 175 genotypes of different wheat types grown under similar conditions to screen for natural diversity. The main focus was on bread wheats, including 130 and 20 winter and spring types, respectively. The average total content of tocopherols and tocotrienols was 49.4 microg/g of dm, with a range of 27.6-79.7 microg/g of dm, indicating a 2.9-fold variation among genotypes. Beta-tocotrienol and alpha-tocopherol were the major vitamers, and in general there were more tocotrienols than tocopherols. In the early cultivated forms of wheat the proportion of tocotrienols was especially high, at >or=62.5%. In conclusion, there was a large variation in total tocopherol and tocotrienol contents in bread wheats and this, along with the high proportions of tocotrienols in other types of wheat, demonstrates the great genetic potential of genotypes to be exploited by plant breeders.     

Folate in wheat genotypes in the HEALTHGRAIN Diversity Screen

As part of the diversity screen of the HEALTHGRAIN project, the total folate contents of bread wheat (130 winter and 20 spring wheat genotypes), durum wheat (10 genotypes), earlier cultivated diploid einkorn and tetraploid emmer wheat (5 genotypes of each), and spelt (5 genotypes), grown in the same location in a controlled manner, were determined by a microbiological assay. The total folate contents ranged from 364 to 774 ng/g of dm in winter wheat and from 323 to 741 ng/g of dm in spring wheat, thus showing a marked variation. The highest mean for total folate content was measured in the durum wheat genotypes, whereas the earlier cultivated diploid and tetraploid wheat genotypes and spelt were shown to possess comparable or even higher folate contents than bread wheat. HPLC analysis of selected genotypes showed that 5-formyltetrahydrofolate was the major vitamer. The data provide a basis for breeding wheat genotypes with improved folate content.     

Phytosterols in wheat genotypes in the HEALTHGRAIN Diversity Screen

The phytosterol contents of 130 winter wheat, 20 spring wheat, 10 durum wheat, 5 spelt, 5 einkorn, and 5 emmer wheat genotypes, grown at the same location in the same year, were analyzed with gas chromatography. Considerable variation was observed in total phytosterol contents in all wheat types. The total sterol contents ranged from 670 to 959 microg/g of dm in winter wheat and from 797 to 949 microg/g of dm in spring wheat. The highest sterol contents were found in spelt, durum wheat, and einkorn wheat. The proportions of the main phytosterols also varied substantially among the different genotypes. The most abundant phytosterol in all wheat genotypes was sitosterol (40-61% of total sterols), whereas the highest variation was seen in total stanols (7-31% of total sterols). The comprehensive data set produced in this study constitutes a valuable basis for plant breeding and selection of phytosterol-rich genotypes.     

The HEALTHGRAIN Cereal Diversity Screen: concept, results, and prospects

One hundred and fifty bread wheat lines and 50 other lines of small-grain cereals (spelt, durum wheat, Triticum monococcum, Triticum dicoccum, oats, rye, and barley) were selected for diversity in their geographical origin, age, and characteristics. They were grown on a single site in Hungary in 2004-2005, harvested, milled, and analyzed for a range of phytochemicals (tocols, sterols, phenolic acids, folates, alkylresorcinols) and fiber components that are considered to have health benefits. Detailed analyses of these components in the different species are reported in a series of accompanying papers. The present paper discusses the comparative levels of the bioactive components in the different species, showing differences in both ranges and mean amounts. Furthermore, detailed comparisons of the bread wheat lines show that it is possible to identify lines in which high levels of phytochemicals and dietary fiber components are combined with good yield and processing quality. This means that commercially competitive lines with high levels of bioactive components are a realistic goal for plant breeders.     

Composition and end-use quality of 150 wheat lines selected for the HEALTHGRAIN Diversity Screen

The HEALTHGRAIN program is focused on developing new healthy food products based on wholegrains of wheat and other cereals, by combining enhanced nutritional quality with good agronomic performance and processing quality. A sample set comprising 130 winter and 20 spring wheat varieties was therefore selected to identify the range of variation in a number of phytochemical and dietary fiber components. These lines were also analyzed for their technological properties (protein and gluten contents, Zeleny sedimentation, bran yield, kernel hardness, etc.), using samples grown on adjacent sites for two successive seasons (2004-2005, 2005-2006). On the basis of the frequency distribution and principal component analysis it was concluded that significant variation for technological quality traits is present in the 150 wheat lines and that it is possible to combine enhanced nutritional quality with good agronomic performance and processing properties.     

Diversity between some Ethiopian farmer's varieties of barley and within these varieties among seed sources

Barley is one of Ethiopia's major crops. Cultivation is mostly by traditional varieties that are chosen by farmers for their suitability for end-use or their adaptation to specific farming systems. A collection of 155 barley lines was grouped in 13 varieties, according to the name given by the farmers. The collection was evaluated for simple agronomic traits and resistance to barley scald disease. A large level of diversity was found, mainly between varieties, but also within varieties between farms from which the samples originated. In spite of a certain degree of overlapping, these traditional farmer's varieties showed coherence for the characters measured. Earlier maturing varieties were found to be more susceptible to scald, but a number of accessions combined earliness with scald resistance. It is suggested that the traditional variety name be included, next to the physical characters of the collection site, as a parameter to explain the degree of diversity in Ethiopian barley germplasm evaluation. The cultivated area of a number of traditional barley varieties is declining rapidly and special collection missions are needed to preserve this germplasm.     

Phytochemical profiles and antioxidant activity of wheat varieties

Whole grain consumption has been associated with reduced risk of chronic diseases, such as cardiovascular diseases and cancer. These beneficial effects have been attributed to the unique phytochemicals of grains that complement those found in fruits and vegetables. Wheat is one of the major grains in the human diet; however, little is known about the inherent varietal differences in phytochemical profiles, total phenolic and carotenoid contents, or total antioxidant activities of different wheat varieties, which ultimately influence the associated nutritional and health benefits of wheat and wheat products. The objectives of this study were to determine the phytochemical profiles and total antioxidant activity for 11 diverse wheat varieties and experimental lines. The profiles included free, soluble-conjugated, and insoluble-bound forms of total phenolics, flavonoids, and ferulic acids and carotenoid content including lutein, zeaxanthin, and beta-cryptoxanthin. The results showed that total phenolic content (709.8-860.0 micromol of gallic acid equiv/100 g of wheat), total antioxidant activity (37.6-46.4 micromol of vitamin C/g), and total flavonoid content (105.8-141.8 micromol of catechin equiv/100 g of wheat) did not vary greatly among the 11 wheat lines. However, significant differences in total ferulic acid content (p < 0.05) and carotenoid content (p < 0.05) among the varieties were observed, with carotenoid content exhibiting the greatest range of values. Carotenoid content among the 11 wheat varieties exhibited 5-fold, 3-fold, and 12-fold differences in lutein, zeaxanthin, and beta-cryptoxanthin, respectively. A synthetic wheat experimental line, W7985, gave the lowest carotenoid concentrations of any of the genotypes in this study. Such large genotypic differences in carotenoid content may open up new opportunities for breeding wheat varieties with higher nutritional value.     

Relationship between the contents of bioactive components in grain and the release dates of wheat lines in the HEALTHGRAIN diversity screen

The EU FP6 HEALTHGRAIN has generated an extensive database on the contents of phytochemicals (alkylresorcinols, tocols, sterols, phenolic acids, folates) and dietary fiber components in the grain of wheat, including analyses of 150 lines grown on a single site in Hungary in 2005 and a smaller set of lines grown under five (three lines) or six (23 lines) different environments (in Hungary in 2005, 2006, and 2007 and in France, Poland, and the United Kingdom in 2007). The lines analyzed included land races and varieties bred between the mid-19th and early 21st centuries. These results have been analyzed to determine whether the contents of these groups of bioactive components in the grain have decreased with the development of intensive plant breeding in the second part of the 20th century. No decreases in the contents of any groups of bioactive components were observed in relation to release date, showing that selection for increased yield and protein quality has been effectively neutral for other grain components.     

中国茶树品种多样性探析

从生物多样性角度对我国 36 7个茶树品种特征特性 ,特别是树型和叶片典型特征研究分析表明 ,中国茶树品种呈多样性结构 ,以灌木和小乔木树型中叶品种为主 ,其次依次为大叶品种、乔木大叶品种和灌木小叶品种。按树型其氨基酸含量为乔木 <小乔木 <灌木 ,茶多酚、咖啡碱含量均为乔木 >小乔木 >灌木。     

Flavanol and bound phenolic acid contents in different barley varieties

Different barley varieties, consisting of hulled and hull-less types, of normal, waxy, and high amylose starch, as well as two-rowed and six-rowed types, were analyzed for their main proanthocyanidins and bound phenolic acids. Variations in proanthocyanidin and phenolic acid contents were studied in different barley types as well as inter-relationships between the phytochemicals and polysaccharides. The main flavanols found in the analyzed barley varieties were two dimeric as well as four trimeric forms in addition to catechin. The total amount of flavanols ranged from 325 to 527 microg/g of fresh weight of barley flour. No evident associations were found between variations in proanthocyanidin levels and different barley types. The total amount of phenolic acids ranged from 604 to 1346 microg/g of fresh weight of barley flour, with ferulic acid as the dominating acid. The amount of phenolic acids varied according to occurrence or lack of hull, with significantly higher levels in the hulled varieties.     

Determination of ergosterol levels in barley and malt varieties in the Czech Republic via HPLC

Ergosterol is considered to be a suitable indicator of mold infestation in barley and malt. In this study ergosterol levels in different varieties of barley and malt produced in the Czech Republic were determined. A modified high-performance liquid chromatography (HPLC) method was statistically processed, validated (Effivalidation program), and applied to 124 samples of barley and malt. Ergosterol was isolated by extraction and saponification, and the quantification was performed using HPLC with diode array detection. The content of ergosterol ranged between the limit of detection (LOD) and 36.3 mg/kg in barley and between the LOD and 131.1 mg/kg in malt. Ergosterol is presumably connected with metabolites generated when barley grain is attacked by pathogens, and such barley often shows a high overfoaming (gushing) value. However, it was found that the content of ergosterol does not correlate with the degree of beer gushing.     

Phytochemical profile of main antioxidants in different fractions of purple and blue wheat, and black barley

Two pigmented wheat genotypes (blue and purple) and two black barley genotypes were fractionated in bran and flour fractions, examined, and compared for their free radical scavenging properties against 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (Trolox equivalent antioxidant capacity, TEAC), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), phenolic acid composition, carotenoid composition, and total anthocyanin content. The results showed that fractionation has a significant influence on the antioxidant properties, TPC, anthocyanin and carotenoid contents, and phenolic acid composition. Bran fractions had the greatest antioxidant activities (1.9-2.3 mmol TEAC/100 g) in all four grain genotypes and were 3-5-fold higher than the respective flour fractions (0.4-0.7 mmol TEAC/100 g). Ferulic acid was the predominant phenolic acid in wheat genotypes (bran fractions) while p-coumaric acid was the predominant phenolic acid in the bran fractions of barley genotypes. High-performance liquid chromatography analysis detected the presence of lutein and zeaxanthin in all fractions with different distribution patterns within the genotypes. The highest contents of anthocyanins were found in the middlings of black barley genotypes or in the shorts of blue and purple wheat. These data suggest the possibility to improve the antioxidant release from cereal-based food through selection of postharvest treatments.     

Diversity in Phytochemical Composition and Antioxidant Capacity of Dent,Flint, and Specialty Corns

Dent, flint, and specialty genotypes of Indian yellow maize were evaluated for phytochemical content and their hydrophilic antioxidant capacity. Solid‐phase extraction coupled with solid–liquid extraction was used to obtain free phenolics and flavonoids from maize samples, reducing the use of excessive solvents and handling time. Bound phenolics were extracted with enhanced acidic hydrolysis to improve extractability. The phenolic contents in Indian maize genotypes ranged from 46 to 79 μmol of ferulic acid equivalents per gram of sample on a dry basis (db). Carotenoids in Indian maize genotypes were found to be equivalent to Chinese yellow maize and ranged from 13 to 24 μg/g of sample (db), whereas tocol content varied greatly in the range of 607–1,238 μg of α‐tocopherol equivalents/g of sample (db). Dent and flint corn did not exhibit differences (P > 0.05) in their phenolic contents, whereas among the specialty genotypes sweet corn contained the highest phenolics but least carotenoids (P < 0.05). Bound extracts appeared to contribute largely to 2,2′‐diphenyl‐1‐picrylhydrazyl free radical scavenging, hydrogen peroxide scavenging, and ferric reducing antioxidant power of maize genotypes. Sweet corn exhibited higher antioxidant capacity (P < 0.05) among all the genotypes. The antioxidant capacities correlated well with the total phenolic contents of the maize genotypes.     

Traditional seed management and genetic diversity in barley varieties in high-hill agro-ecosystems of Nepal

Chawali and Lekali are two common farmer’s barley varieties or landraces in Jumla, Nepal (2,240–3,000 m) with small to bold grains and wide adaptation from irrigated low lands to high hills. This study was undertaken to test whether features of the traditional seed system can significantly influence the diversity of a crop and its conservation on-farm. In Jumla (high-hill), the barley seed system is completely informal and is mainly from farmer to farmer. In the present study, the seed flows and the pattern of genetic diversity in barley were investigated to detect differences between the two varieties and test the divergence among populations of each variety These data suggested that Chawali, the more common variety, was less subject to homogenising gene flow between farms than was Lekali. A total of 128 farming households were surveyed for seed supply information and 128 populations for each landrace from two villages: Kartikswami and Talium were collected for SSR diversity analysis. Some 92 SSRs were screened in an initial sample of 20 barley populations of both landraces and 2 improved varieties (LG-51 and Soluwa). Of the 81 SSRs that consistently amplified, only 15 SSRs (19%) were polymorphic with gene diversity values ranging from 0.09 to 0.71. A medium to low diversity was detected among the landrace populations of barley varieties. Chawali populations were less polymorphic within ecological groups, and more divergent between than were Lekail populations. This result accords with Chawali having a more conservative local seed system.