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.     

Comparison of black,purple, and yellow barleys

Many barley landraces are purple-or black-seeded, but the chemical composition of these purple-and black- seeded barley is rarely examined. Therefore, studies were conducted to determine if the chemical composition of purple and black barleys differs from that of yellow barleys. Four sets of genetic materials were used for these studies: 96 doubled-haploid (DH) lines, 10 near-isogenic lines, 40 landraces, and four F3 bulks. The results showed that purple DH lines contained a similar amount of lignin as yellow DH lines and that anthocyanin-containing isogenic lines did not differ from anthocyanin-free lines in lignin content. Therefore, these results suggest that anthocyanin biosynthesis is independent of lignin biosynthesis in barley. The results also showed that black barley contained more protein and more lignin than yellow barley in two crosses and that among the 40 landraces studied, the three with the highest concentration of lignin happened to be black seeded. Lignin content was not associated with seed weight except in defective endosperm lines. The presence of pigments and a relatively high concentration of lignin might help reduce the level of kernel blight severity in black barley. More studies are needed to determine the chemical composition and pest resistance associated with purple and black barleys.     

Lignins and ferulate-coniferyl alcohol cross-coupling products in cereal grains

Plant cell walls containing suberin or lignin in the human diet are conjectured to protect against colon cancer. To confirm the existence of authentic lignin in cereal grain dietary fibers, the DFRC (derivatization followed by reductive cleavage) method was applied to different cereal grain dietary fibers. By cleavage of diagnostic arylglycerol-beta-aryl (beta-O-4) ether linkages and identification of the liberated monolignols, it was ascertained that lignins are truly present in cereal grains. From the ratios of the liberated monolignols coniferyl alcohol and sinapyl alcohol, it is suggested that lignin compositions vary among cereals. Furthermore, dimeric cross-coupling products, comprising ferulate and coniferyl alcohol, were identified in most cereal fibers investigated. These ferulate 4-O-beta- and 8-beta-coniferyl alcohol cross-coupled structures indicate radical cross-coupling of polysaccharides to lignin precursors via ferulate.     

重庆地区紫色土和紫色泥岩物质组成与微结构研究

根据紫色土与紫色泥岩的X-射线矿物鉴定、粒度分析、电镜鉴定及野外观察,研究了紫色土与紫色泥岩的矿物组成、粒度组成及其易发生侵蚀的原因。结果表明,紫色土与紫色泥岩矿物成分与含量差异很小,均以石英和长石为主,黏土矿物中蒙脱石含量较其他矿物多;粒度成分也非常接近,以粉砂和黏粒为主。紫色土以碎屑粒状孔隙充填式胶结微结构为主,另有少量粒状接触胶结微结构和粒状块状胶结微结构,胶结物以黏土为主,仅含有3%左右的Fe2O3化学胶结物;紫色泥岩微结构的突出特点是微型片结构和微型块状结构占主要地位。蒙脱石的较高含量指示紫色泥岩与紫色土为膨胀类岩土。紫色泥岩与紫色土在湿润气候条件下的频繁胀缩是它们易于发生物理风化和易受侵蚀的主要原因,微型块状结构、微型片状结构和密集微型裂隙也是其抗蚀性差的重要原因。紫色泥岩的微型块状与微型片状结构和密集微型裂隙主要是在成岩过程中产生的,是原始沉积形成的大量球形、椭球形黏土形态受到成岩过程中挤压作用的结果。     

Anthocyanin composition of wild bananas in Thailand

Anthocyanins were isolated from male bracts of 10 wild species of bananas (Musa spp. and Ensete spp.) distributed in Thailand. Six major anthocyanin pigments were identified by high performance liquid chromatography (HPLC), mass spectrometry (MS), and tandem mass spectrometry (MS/MS). They are delphinidin-3-rutinoside (m/z 611.2), cyanidin-3-rutinoside (m/z 595.8), petunidin-3-rutinoside (m/z 624.9), pelargonidin-3-rutinoside (m/z 579.4), peonidin-3-rutinoside (m/z 608.7), and malvidin-3-rutinoside (m/z 638.8). On the basis of the types of pigment present, the wild bananas can be divided into 5 groups. The first group comprises M. itinerans, Musa sp. one, Musa sp. two, and M. acuminata accessions, which contain almost or all anthocyanin pigments except for pelargonidin-3-rutinoside, including both nonmethylated and methylated anthocyanins. The second group, M. acuminata subsp. truncata, contains only malvidin-3-rutinoside while the third group, M. coccinea, contains cyanidin-3-rutinoside and pelargonidin-3-rutinoside. The forth group, M. acuminata yellow bract and E. glaucum do not appear to contain any anthocyanin pigment. The fifth group consists of M. balbisiana, M. velutina, M. laterita, and E. superbum which contain only nonmethylated anthocyanin, delphinidin-3-rutinoside, and cyanidin-3-rutinoside. Total anthocyanin content in the analyzed bracts ranged from 0-119.70 mg/100 g bract fresh weight. The differences in the type of anthocyanin and variation in the amounts present indicate that wild bananas show biochemical diversity, which may be useful for identifying specific groups of bananas or for clarifying the evolution of flavonoid metabolism in each banana group.     

Effects of genotype and environment on the contents of betaine, choline, and trigonelline in cereal grains

This study examined the environmental and genetic variation in methyl donor contents and compositions of 200 cereal genotypes. Glycine betaine, choline, and trigonelline contents were determined by (1)H NMR, and significant differences were observed between cereal types (G) and across harvesting years and growing locations (E). Glycine betaine was the most abundant methyl donor in all of the 200 lines grown on a single site, and concentrations ranged from 0.43 ± 0.09 mg/g dm in oats to 2.57 ± 0.25 mg/g dm in diploid Einkorn varieties. In bread wheat genotypes there was a 3-fold difference in glycine betaine content. Choline contents, in the same lines, were substantially lower, and mean concentrations ranged from 0.17 mg/g dm in oats to 0.27 mg/g dm in durum wheat. Trigonelline was by far the least abundant of the methyl donors studied. Despite this, however, there were large differences between cereal types. Twenty-six wheat genotypes were grown in additional years at four European locations. The average glycine betaine content was highest in grains grown in Hungary and lowest in those grown in the United Kingdom. Across the six environments, there was a 3.8-fold difference in glycine betaine content. Glycine betaine levels, although moderately heritable (0.36), were found to be the most susceptible to the environmental conditions. Free choline concentrations were less variable across genotypes, but heritability of this component was the lowest of all methyl donor components (0.25) and showed a high G × E interaction. Trigonelline showed the most variation due to genotype. Heritability of this metabolite was the highest (0.59), but given that it is at a very low concentration in wheat, it is probably not attractive to plant breeders.     

Chemical composition of distillers grains, a review

In recent years, increasing demand for ethanol as a fuel additive and decreasing dependency on fossil fuels have resulted in a dramatic increase in the amount of grains used for ethanol production. Dry-grind is the major process, resulting in distillers dried grains with solubles (DDGS) as a major coproduct. Like fuel ethanol, DDGS has quickly become a global commodity. However, high compositional variation has been the main problem hindering its use as a feed ingredient. This review provides updated information on the chemical composition of distillers grains in terms of nutrient levels, changes during dry-grind processing, and causes for large variation. The occurrence in grain feedstock and the fate of mycotoxins during processing are also covered. During processing, starch is converted to glucose and then to ethanol and carbon dioxide. Most other components are relatively unchanged but concentrated in DDGS about 3-fold over the original feedstock. Mycotoxins, if present in the original feedstock, are also concentrated. Higher fold of increases in S, Na, and Ca are mostly due to exogenous addition during processing, whereas unusual changes in inorganic phosphorus (P) and phytate P indicate phytate hydrolysis by yeast phytase. Fermentation causes major changes, but other processing steps are also responsible. The causes for varying DDGS composition are multiple, including differences in feedstock species and composition, process methods and parameters, the amount of condensed solubles added to distiller wet grains, the effect of fermentation yeast, and analytical methodology. Most of them can be attributed to the complexity of the dry-grind process itself. It is hoped that information provided in this review will improve the understanding of the dry-grind process and aid in the development of strategies to control the compositional variation in DDGS.     

Liquid chromatographic determination and stability of the Fusarium mycotoxin moniliformin in cereal grains

Moniliformin is a mycotoxin produced by Fusarium subglutinans and other Fusarium species. A rapid, liquid chromatographic method for its determination in corn and wheat is described. Samples are extracted in acetonitrile-water (95 + 5); following defatting with n-hexane, an aliquot of the extract is evaporated and cleaned up on small C18 and neutral alumina columns successively. Reverse-phase liquid chromatography (LC) is conducted on a C18 column with 10 or 15% methanol or acetonitrile in aqueous ion-pair reagent as mobile phase, with detection by ultraviolet absorption at 229 and 254 nm. Average recoveries of moniliformin (potassium salt) added to ground corn and wheat at levels of 0.05-1.0 micrograms/g were 80% (n = 20) and 85% (n = 12), respectively, and the limit of detection was ca 0.01-0.18 micrograms/g, depending on LC conditions. Analysis of 24 samples of wheat, 4 samples of rye, and 12 samples of corn showed moniliformin in only 2 corn samples (0.06 and 0.2 micrograms/g). Moniliformin was also detected in a sample of artificially damaged (slashed) corn (0.2 micrograms/g) and selected kernels of corn that were field-inoculated with F. subglutinans and F. moniliforme (50 micrograms/g and 0.5 micrograms/g, respectively). In stability studies, moniliformin (potassium salt, 1 microgram/g) in ground corn and ground wheat heated at 50, 100, and 150 degrees C for 0.5-2 h decomposed moderately, e.g., 55% remained in corn after 0.5 h at 100 degrees C.     

Antioxidant activity and total phenolics in selected cereal grains and their different morphological fractions

The purpose of this study was to examine the antioxidant properties of water and 80% methanolic extracts of cereal grains and their different morphological fractions. Wheat (Triticum aestivum L.) cv. Almari and cv. Henika, barley (Hordeum vulgare L.) cv. Gregor and cv. Mobek, rye (Secale cereale L.) cv. Dańkowskie Zlote, oat (Avena sativa L.) cv. Slawko and buckwheat (Fagopyrum esculentum Moench) cv. Kora were used. PC (L-alpha-phosphatidylcholine) liposome system and spectrophotometric assay of total antioxidant activity (TAA) were used to evaluate the antioxidative activity of extracts. Among the water extracts, only the one prepared from buckwheat exhibited antioxidant activity at the concentration analyzed. The following hierarchy of antioxidant activity was provided for 80% methanolic extracts originated from whole grain: buckwheat > barley > oat > wheat congruent with rye. The antioxidant activity was observed in extract prepared from separated parts of buckwheat and barley. In respect to hulls, the antioxidant hierarchy was as follows: buckwheat > oat > barley. The correlation coefficient between total phenolic compounds and total antioxidative activity of the extracts was -0.35 for water extracts and 0.96, 0.99, 0.80, and 0.99 for 80% methanolic extracts originated from whole grains, hulls, pericarb with testa fractions and endosperm with embryo fractions, respectively.     

Comparative evaluation of the antioxidant potential of infant cereals produced from purple wheat and red rice grains and LC-MS analysis of their anthocyanins

Cellular oxidative damage by endogenous and exogenous sources of free radicals and reactive oxygen species is a particular threat in infants. Antioxidant protection is normally achieved through a balance between pro-oxidants and endogenous and/or dietary antioxidants. Comprehensive research is required on optimization to achieve good antioxidant protection through infant foods, in particular, the commercially available infant cereals. This study therefore investigated the properties of whole purple wheat, unpolished red rice, and partially polished red rice before and after processing to produce infant cereals. Total phenolic content (TPC), total anthocyanin content (TAC), oxygen radical absorbance capacity (ORAC), individual anthocyanin components, and cellular antioxidant activity were measured. Home-made and laboratory-made pigmented infant cereals differed in that the latter required longer exposure to higher temperature and enzymatic hydrolysis. Home-made and laboratory-made unpolished red rice infant cereals showed higher total phenolic contents and peroxyl radical scavenging activity than home-made and laboratory-made purple wheat infant cereals; however, the latter had higher TAC. Pigmented infant cereals generally had higher TPC, TAC, and ORAC than the commercial ones (p < 0.05). Anthocyanins were identified in whole purple wheat, but they were not detected in unpolished red rice. C-Glycosyl apigenin was found in both whole purple wheat and unpolished red rice. Processing significantly decreased anthocyanin and C-glycosyl apigenin contents (p < 0.05). Purple wheat infant cereals had higher cellular antioxidant activity than unpolished red rice ones (p < 0.05). Whole purple wheat infant cereals showed higher antioxidant activity than the commercial infant cereal, suggesting a possibility of improving infant antioxidant status by incorporating this grain in their diet.     

Anthocyanin composition of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) cultivars Antonina, Beta Sweet, Deep Purple, and Purple Haze

This study aimed to identify the pigment composition of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) cultivars Antonina, Beta Sweet, Deep Purple, and Purple Haze. Cyanidin 3-xylosyl(glucosyl)galactosides acylated with sinapic acid, ferulic acid, and coumaric acid were detected as major anthocyanins by high-performance liquid chromatography with diode array detection (HPLC-DAD) and with electrospray ionization multiple mass spectrometry (HPLC-ESI-MS(n)) analyses. The preparative isolation of these pigments was carried out by means of high-speed countercurrent chromatography (HSCCC). The color activity concept was applied to the isolated anthocyanins at three pH values. Cyanidin 3-xylosyl(sinapoylglucosyl)galactoside was found to exhibit a lower visual detection threshold and a higher pH stability than cyanidin 3-xylosyl(feruloylglucosyl)galactoside and cyanidin 3-xylosyl(coumaroylglucosyl)galactoside. The color parameters of the fresh roots of the four cultivars were described by the CIELab coordinates L* (lightness), C* (chroma), and h(ab) (hue angles). Total phenolics varied among the cultivars and ranged from 17.9 to 97.9 mg gallic acid equivalents (GAE)/100 g fresh weight (fw). For the content of monomeric anthocyanins, values between 1.5 and 17.7 mg/100 g fw were determined.     

Determination of ochratoxin A in animal feed and cereal grains by liquid chromatography with fluorescence detection

A liquid chromatographic (LC) method is described for determination of ochratoxin A in animal feeds and cereal grains. Samples are initially extracted with chloroform-ethanol (8 + 2) and 5% acetic acid in water. Extracts are purified using a silica gel cartridge followed by a cyano cartridge. The samples are evaporated, diluted to a known volume, and analyzed using a 10 cm column of 3 micron C18 and a fluorescence detector. The method was applied to a variety of animal feeds and cereal grains at levels of 1.0-0.005 ppm added ochratoxin A. The overall recovery was 90.6% +/- 3.6.     

Caffeoylsophorose in a red vinegar produced through fermentation with purple sweetpotato

Recently, a new red vinegar has been developed via fermentation with the storage root of purple-fleshed sweetpotato, Ipomoea batatas L. cv. Ayamurasaki. The red vinegar had a higher antioxidative activity than white or black vinegars. The red vinegar contained some new components possibly derived from the original purple sweetpotato. A major component was isolated using preparative HPLC, and the chemical structure was determined to be 6-O-(E)-caffeoyl-(2-O-beta-d-glucopyranosyl)-alpha-d-glucopyranose (caffeoylsophorose) by MS and NMR. Because the caffeoylsophorose showed a high antioxidative activity, it plays an important functional role in red vinegar as do anthocyanins and other components. Examination of the mechanism of formation is now in progress.     

Changes in anthocyanins in the grains of purple waxy hull-less barley during seed maturation and after harvest

Purple waxy hull-less barley cv. Daishimochi accumulates purple pigments in the stem, awn, lemma, palea, and pericarp during seed maturation. Four major anthocyanin constituents from the grains of cv. Daishimochi were isolated and identified as cyanidin 3-O-(3,6-di-O-malonyl-beta-D-glucopyranoside) (55%), cyanidin 3-O-(6-O-malonyl-beta-D-glucopyranoside) (21%), cyanidin 3-O-(3-O-malonyl-beta-D-glucopyranoside) (12%), and cyanidin 3-O-beta- d-glucopyranoside (4%) by mass spectrometry and one- and two-dimensional NMR spectroscopy. These anthocyanins were observed after 28 days after flowering (DAF); they were most abundant at 35 DAF when the dry weight of grains was maximum. This accumulation time was later than that of proanthocyanidins, which are the most abundant polyphenol constituents in barley grains. These anthocyanins, especially cyanidin 3-O-(3,6-di-O-malonyl-beta- d-glucopyranoside), decreased at 42 DAF and during drying preparation after harvest. Most anthocyanins are localized in the outer parts of grains and distributed into bran by the pearling process. Whole grain flour and bran of cv. Daishimochi are good sources of malonylated cyanidin derivatives.     

Methodological aspects of measuring phytase activity and phytate phosphorus content in selected cereal grains and digesta and feces of pigs

This study was to examine the time course of sample-specific linearity of intrinsic phytase hydrolysis in major cereal grains and in ileal digesta and fecal samples and to determine the time course of the microbial phytase-catalyzed hydrolysis of various sources of phytate for estimating phytate phosphorus (P) content. The intrinsic phytase activity in barley, corn, oat, and wheat samples was measured over multiple time points from 0 to 120 min at 1.5 mmol.L(-1) of sodium phytate at pH 5.5 and 37 degrees C. Time courses of hydrolysis of purified phytate and phytate associated with the cereal grain samples and the pig digesta and fecal samples were examined with the Natuphos microbial phytase over multiple time points from 0 to 48 h of incubation. The intrinsic phytase hydrolysis was linear (P < 0.05) for up to 120 min for the barley, corn, and wheat samples, whereas in the oat sample the hydrolysis was linear (P < 0.05) for only up to 30 min of incubation. The intrinsic phytase activities (phytase unit: mumol.kg(-1) of dry matter.min(-1)) for the barley, corn, and wheat samples were estimated to be 693, 86, and 1189 by linear regression analysis. Intrinsic phytase activity (412 phytase units) for the oat sample based on a 30-min incubation was considerably higher than the value (103 phytase units) determined from the 120-min incubation for the same oat sample. There were quadratic with plateau relationships (P < 0.05) between the hydrolytic release of inorganic P from various sources of phytate and the incubation time. The minimal incubation times required for the complete hydrolysis of phytate were estimated to be 4, 3, and 11 h for the purified phytate, the cereal grain samples, and the pig digesta and feces, respectively. It was concluded that multiple time point experiments need to be conducted to determine valid intrinsic phytase activity and phytate P content in samples through intrinsic and microbial phytase hydrolysis incubations.