Rye Samples Research Articles

On ochratoxin A and fungal flora in Polish cereals from conventional and ecological farms - Part 1: Occurrence of ochratoxin A and fungi in cereals in 1997

Over 200 samples of Polish cereal grain from the 1997 harvest obtained from conventional and ecological farms were tested for the presence of ochratoxin A as well as for contamination by microscopic fungi. Ochratoxin A contamination of rye from ecological farms was over six times more frequent than that from conventional cultivation. The ochratoxin A content in wheat and barley samples from ecological farms was also higher. No wheat sample from conventional farms contained the mycotoxin. In the group of ecological farms, there were differences in the percentage of cereal samples containing ochratoxin A. The ochratoxin A levels ranged from 0.2 to 57 µg kg−1. The mean concentration of ochratoxin A in investigated cereal grain was 5.7 µg kg−1. From samples containing detectable amounts of ochratoxin A, fungi producing ochratoxin A under laboratory conditions were isolated. They were classified as belonging to the species Penicillium cyclopium, P. viridicatum, P. chrysogenum and also Aspergillus alliaceus, A. versicolor, A. glaucus and A. flavus. Penicillium strains—producers of ochratoxin A—were isolated from 93% of the samples; in 7% of samples, only Aspergillus strains producing this mycotoxin were noted. Rye samples mainly from one farm with an ecological type of cultivation and from one conventional farm were contaminated with both Aspergillus and Penicillium mycotoxigenic strains.

Monitoring of fusarium toxins in cereals and feed-stuffs from thuringia (1998 - 2001)

From 1998 to 2001 a total of about 1172 conventionally and organically produced samples of wheat, rye, barley and triticale were examined for the presence of deoxynivalenol (DON) and zearalenone (ZON). Furthermore, feedstuffs for pigs were included in the monitoring of Fusarium toxins. DON and ZON analyses were performed using ELISA or HPLC. The incidences and levels of toxins varied from year to year. Overall contamination levels were highest in wheat and triticale, followed by rye and barley. The highest DON contaminations were found in 1998. The probes of the years 1999-2001 showed lower incidences of Fusarium toxins. The second examined mycotoxin ZON was detected at lower levels in cereals. Similar results were observed in the monitoring of feedstuffs.

Transfer of137Cs and90Sr from finnish soils to cereal grains

The transfer of 137 Cs and 90 Sr from soil to cereal grains in various regions in Finland was studied in 1994-1997. The samples of cereal grains were collected from private farms and combined to represent different soil types and regions in Finland. Altogether 318 composite regional samples of rye, wheat, oats and barley were analysed for 137 Cs, and 45 for 90 Sr. The aggregated transfer factors from the mean regional 137 Cs deposition (kBq m-2 ) to cereal grains were calculated. The soils were classified in three main types: organic, sand and silt, and clay soils. The mean transfer factors (m2 kg-1 (dw)*10-3 ) of 137 Cs for cereal grains were highest in organic soils ranging from 0.013 to 0.12, lowest in clay soils, ranging from 0.015 to 0.061, and decreased in the order : oats > rye > barley on wheat. The concentrations of 90 Sr were higher in the cereal grains from sand and silt soils than from the clay and organic soils. The regional 137 Cs transfer factors from soil to cereal grains found in this study were compared with data for the nuclear weapons fallout period and for a few post-Chernobyl years.

Alternations in phenolic acids content in developing rye grains in normal environment and during enforced dehydration

A series of high pressure liquid chroamtography analyses revealed the presence of five phenolic acids in rye caryopses (vanillic, caffeic, p-coumaric, ferulic and sinapic), three of which (p-coumaric, ferulic and sinapic) were found in the free phenolic fraction. Ferulic acid was predominant, both among free acids and total phenolic acids (i.e. free, liberated from soluble esters and glycosides). The highest content of the free phenolic acids in rye caryopses was observed at the beginning of development, when on 22 DAF it was estimated at 11.55 µg·g−1 DW. During dehydratation the total level of free phenolic acids in rye caryopses decreased in all investigated samples. Although total phenolic acids contents in all samples of unripe rye caryopses always decreased after dehydration, in rye sample collected in full ripeness (57 DAF), the amount of these compounds increased after the enforced dehydration. It should be added that in ester-bound-soluble phenolic acids fraction (the largest part in the total phenolic acids fraction), irrespective of the total amount decrease, much increase of sinapic acid content in this fraction was observed after dehydratation treatment in all investigated samples of caryopses of various ripeness. During the development and ripening of rye caryopses, a gradual increase in the precocious germination ability of the grain was observed. The enforced dehydration stimulated the process of precocious germination of developing and ripening rye caryopses. A possible role of phenolics in preventing precocious germination and acclimation to dehydration of developing and ripening rye grains is discussed.

Structural and Enzymic Changes in Germinated Barley and Rye

Germination of barley and rye grains at 15°C and 56% moisture content resulted in the production of α-amylase, β-glucanase, endo-β-xylanase and α-arabinosidase, During germination of rye, enzyme activity increased significantly after the first day, whereas in the case of barley a rapid increase was not observed until after the third or fourth day. Rye varieties produced more xylanase, whereas barley produced more α-amylase and β-glucanase. Of the barley samples, germinated Pokko had the highest activities of β-glucanase, xylanase and α-amylase, and at 46% moisture content highest degradation of cell walls on the basis of image analysis. Arve had the highest a-arabinofuranosidase activity. Of the rye samples, Amando produced more xylanase and α-arabinosidase than Anna. The M w of barley and rye β-glucan decreased significantly during germination. In rye samples, residual high molecular weight arabinoxylans were still present after 4 days of germination. The mass average molecular weight (M w ) of this fraction was 3 x 10 6 .

Structure and Potential Allergenic Character of Cereal Proteins II. Potential Allergens in Cereal Samples

Protein electrophoretic patterns and immunblot analysis were investigated in 30 grain samples: different cultivars of 12 cereal species (samples of einkorn, durum wheat, bread wheat, spelt wheat, barley, naked barley, rye, triticale, oat, naked oat, millet and corn) and one buckwheat and one amaranth variety. The gliadin fractions in all wheat, barley, rye, triticale and oat samples show intense reactivity against the rabbit anti-gliadin (wheat) antibodies. The bands are extremely strong in the case of the spelt wheat samples, consequently the consumption of bread and pasta made from the flour of this spelt wheat (Oko 10) species can not be recommended to the patients suffering from gluten sensitivity. However, there are immunreactive zones not in the protein range corresponding to the gliadin fractions with corn and millet samples, whereas no reactivity is observed against the buckwheat and amaranth samples, which do not belong to the cereal species. Electrophoretic methods and immunblot techniques can be used as a tool for detection and identification of prolamin fractions in different cereals or foods in the interest of knowledge of the potential allergenic character and the technological characteristics of flour proteins.

Fusarium mycotoxins in conventionally and organically grown grain from Thuringia/Germany

Thefusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZON) were determined in conventionally and organically grown grain harvested 1998 in Thuringia/Germany. A total of 196 wheat samples and 69 rye samples was analysed.In this year with heavy rainfalls during the summer months, high concentrations offusarium mycotoxins were typical in grain grown in Germany, as the DON concentrations found here. DON concentrations in conventionally grown wheat were found to be significantly higher than in organically grown wheat. 69% of the conventionally grown wheat were tested positive, containing a mean concentration of 1540 µg/kg DM. In 54% of the organically grown wheat samples DON was detected with a mean value of 760 µg/kg DM. DON concentration in rye and ZON concentration in wheat showed similar tendencies.The different cultivars of conventionally grown wheat showed large differences in DON contamination.

The Occurrence of Type A and B Trichothecenes in Lithuanian Cereals

Samples of winter wheat (n =84), winter rye (46) and barley (29) were collected from the larger family farms and from partnerships in Lithuania just after the 1998 harvest. The number of samples collected from each region was proportional to the amount of grain produced in it. The levels of the Fusarium toxins deoxynivalenol (DON), 3-acetyl-DON, 15-acetyl-DON, nivalenol (NIV), fusarenon-X (4-acetyl-NIV), T-2 toxin, HT-2 toxin, 4,5-diacetoxyscirpenol (DAS), 1,5-monoacetoxyscirpenol (MAS) and scirpentriol in the grain were determined by gas chromatography with mass-selective detection (GC-MS). DON was most often detected in the wheat and rye samples and NIV in the barley samples. The concentrations found were lower than those causing acute or chronic toxic effects in livestock or humans. No fusarenon-X or 15-acetyl-DON was detected, and only small amounts of other trichothecenes were present. Climatic conditions in Lithuania in the summer of 1998 were slightly cooler and wetter than the average for the 1992-1996 but were close to the norm. Because the samples analysed were representative of grain produced for the market in seasons with normal weather, trichothecene contamination of grain from large family farms and partnerships would not be expected to be a problem in most years.

Aflatoxin production in three selected samples of triticale, wheat and rye grown in Argentina

Little is known about mycotoxin contamination of triticale, a hybrid resulting from crossing wheat and rye. The purpose of the present work was to evaluate triticale as a substrate for aflatoxin accumulation in comparison with its parents. Aflatoxin (B1, B2, G1 and G2) accumulation curves were obtained for the three substrates inoculated with Aspergillus parasiticus NRRL 2999 and incubated at 25 °C and water activity 0.925 for 10 weeks. Wheat and triticale were poor substrates for aflatoxin production. Rye was more prone than the other substrates to fast colonisation by A parasiticus and accumulated larger aflatoxin quantities over the whole incubation period. The maximum aflatoxin concentration in rye (11 840 µg kg−1) was significantly larger (p < 0.05) than those obtained in wheat (2150 µg kg−1) and triticale (2850 µg kg−1). © 2000 Society of Chemical Industry

Heterogeneity in a water-extractable rye arabinoxylan with a low degree of disubstitution

From rye grain samples, water extractable arabinoxylan with a low degree of disubstitution (AX I) was isolated by fractionation on a DEAE-cellulose column. AX I of all rye samples had a similar relative composition of un- and monosubstituted xylose residues and with less than 5% disubstitution. It showed a shear thinning behaviour and the viscosity was related to molecular weight. AX I isolated from different rye varieties had different viscosities at the same concentration. One rye sample had a weight average molecular weight of 125 000 (polydispersity 2) according to calculations from both light scattering and viscosity data. Signals from un- and monosubstituted xylose residues in 13C NMR spectra were assigned using 13C-HSQC-DEPT and COSY techniques. AX I probably consisted of blocks or different molecules with sparsely and more densely substituted regions.

Residues of Chlormequat and Mepiquat in Grain—Results from the Danish National Pesticide Survey

The objective of the present work was to establish information on chlormequat and mepiquat residues in grain for human consumption. Chlormequat (2-chloro-N,N,N-trimethylethylammonium, CAS RN 7003-89-6) and mepiquat (1,1-dimethylpiperidinium, CAS RN 15302-91-7) are plant growth regulators used to stabilize stalks in cereals. The study was part of the Danish National Pesticide Survey, managed by the Danish Veterinary and Food Administration. Samples were collected in autumn 1997. Residue contents were determined with a newly developed liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method for chlormequat analysis. The method was extended to include mepiquat in the present study. Quantitation was done by the internal standards method, using mass chromatograms of the most intense daughter ions of mepiquat (m/z 98), chlormequat (m/z 58), and [13C]-chlormequat (m/z 61, internal standard). For chlormequat, the overall limit of detection (LD) was 6 micrograms/kg and the limit of determination (LOD) was 10 micrograms/kg. For mepiquat, LD was 2 micrograms/kg and LOD was 3 micrograms/kg. Of 77 samples analyzed, 51 contained chlormequat and 11 contained mepiquat. The highest levels of chlormequat were found in samples of oatmeal (3.76 mg/kg) and rye (1.08 mg/kg). In 9 rye grain samples containing chlormequat, 5 also contained mepiquat. However, in all samples analyzed, the residues of chlormequat and mepiquat were below maximum residue limits.

Use of various clean-up procedures for the analysis of ochratoxin A in cereals

A rapid and reliable procedure has been developed for the determination of ochratoxin A in wheat and oats. The method consists of extraction of the sample with acidic chloroform, followed by defatting with n-hexane and finally, HPLC determination with fluorometric detection. Mean recoveries for wheat and oats spiked at levels between 1 and 100 μg/kg ranged from 80 to 104%. The limit of determination (field blank +6 σ) was 0.8 μg/kg and the precision (within-laboratory relative standard deviation) ranged from 3 to 7%. The method was tested on 34 wheat and 34 oats samples. Ochratoxin A was confirmed in some positive samples by methyl ester formation and/or by clean-up of the extracts with immunoaffinity columns. The method was not appropriate for the analysis of barley (45 tested samples), rye (69 samples) or trout feed (13 samples). A false positive was recorded within the four positive barley samples and 18 false positives were recorded within the 21 positive rye samples whereas trout feed samples could not be analysed due to insufficient clean-up. The use of immunoaffinity columns made the analysis of trout feed and rye samples possible, providing excellent clean-up of the extracts with no false positive results and a good limit of determination (0.2 μg/kg).

Distribution and Some Properties of Cell Wall Polysaccharides in Rye Milling Fractions

A rye sample (cv. Voima) was fractionated by a laboratory scale roller mill into eight fractions: six flour fractions and bran and short fractions originating from the outer kernel layers. The extractabilities of dietary fibre and pentosan were clearly higher in the flour fractions than in the outer fractions. Pentosan and β-glucan were present throughout the kernel in different proportions, although in much higher amounts in the outer parts. The pentosan present in the outer layers was less branched (arabinose:xylose 0·63–0·75) than that in the flour fractions (arabinose:xylose 1·1–1·2). The outer fractions showed the highest water absorption capacities. When extracted with water the fractions yielded solutions with different viscosities, and the shorts extract had clearly the highest viscosity. Extract viscosity was shown to correlate with the content of water-extractable pentosan in the particular fraction. The molecular mass of the solubilised pentosans varied from 150 000 to 800 000 as revealed by size exclusion-HPLC with laser light-scattering detection. The pentosan with lower molecular mass was shown to be less branched than the larger polymers.

Nutrient and lignan content, dough properties and baking performance of rye samples used in Scandinavia

Seven samples of rye with a wide variation in origin were collected from Finland and Sweden. Starch (57–66%), dietary fibre (15–17%) and crude protein (7–13%) were found to be the principal chemical constituents. The arabinoxylan content varied between 8 and 10%, of which 20–38% was water‐extractable. Of the chemical constituents analysed the highest coefficients of variation were found for crude protein, water‐extractable xylose residues and lignan (matairesinol and secoisolariciresinol) content. No correlation was found between the two lignans but a negative correlation was found between mixed‐linked ß‐glucans and secoisolariciresinol. Large variations were also found in the flour, dough and bread parameters measured, especially for parameters which could be related to the arabinoxylan content and arabinoxylan degrading enzymes. Correlations were found between the falling number of the flours, viscosity decrease during the swelling curve test, softening factor of the doughs and percentage decrease of the dough storage modulus, all related to the activity of endogenous hydrolytic enzymes. Notable differences in crumb properties (firmness, elasticity and stickiness) were found in the breads baked from five different whole‐meal flours. No correlation could be found between the dough and bread parameters and the content of lignans measured.

Identification of Cereals using the Polymerase Chain Reaction

Methods based upon the polymerase chain reaction (PCR) have been developed for distinguishing cereal species and cultivars. DNA isolated from the leaves of germinating seedlings or grain gave similar results. Primers designed to amplify the spacers between 5S ribosomal RNA genes were able to identify samples of maize, barley, sorghum, rye, rice, oat and wheat without any significant variation within these species. Arbitrary 10-mers allowed distinction between cultivars of the same species, although some variation was found within cultivars, and some primers gave products characteristic of the cereal species. These methods have potential for application in the analysis of the species and cultivars composition of cereal grain lots and cereal products.

Distribution of α-tocopherol in early foliage samples in several forage crops

Concentrations of α-tocopherol in foliage samples of the forages annual rye, winter rye, red fescue, Kentucky blue-grass and white clover were determined. Concentrations of α-tocopherol increased with age in all four of the grasses tested during the six-week experimental period to values of 70.9, 80.9, 94.0 and 146.7 μg g −1 dry wt in annual rye, winter rye, red fescue and Kentucky blue-grass, respectively. White clover, the only legume forage tested, did not increase α-tocopherol concentrations with age, remaining at about 20 μg g −1 dry wt for each time sample. These results support the hypothesis that concentrations of α-tocopherol may act as indicators of biological age, although exceptions to this concept are likely to exist.

A survey of the occurrence of the mycotoxin moniliformin in cereal samples from sources worldwide

A method is reported for the determination of the Fusarium mycotoxin moniliformin in cereals. The samples after extraction with acetonitrile/water are cleaned-up on a combination of reverse-phase and strong-anion exchange disposable cartridge columns. The extract is then analysed by ion-pair HPLC with UV detection. The method gave recoveries from 81 to 96% and a limit of detection of 0.05 mg/kg. A UK survey of 36 samples of maize products (principally meal and flour) generally showed detectable but low levels of contamination ranging from 0.05 to 0.25 mg/kg (with the exception of three samples where moniliformin levels were less than 0.05 mg/kg). Sixty-four samples of maize from ten different countries showed generally higher levels of moniliformin contamination, with samples from Gambia and South Africa containing 3.16 and 2.73 mg/kg respectively. Field samples of maize, oats, wheat, rye and tricticale that were hand-selected as showing signs of visible fungal damage were obtained from Poland. Moniliformin was consistently present at high levels with amounts ranging from 0.5 to 38.3 mg/kg being associated with F. avenaceum contamination and amounts ranging from 4.2 to 399.3 mg/kg being associated with the presence of F. subglutinans.

Effects of variety and environment on dietary fibre content of winter rye in Finland

The water-insoluble (WISDF) and water-soluble (WSDF) dietary fibre (DF) contents of five winter rye varieties at three locations in two years in Finland as well as those of 10 imported winter rye samples from Canada, the Federal Republic of Germany, Hungary, Sweden, the U.S.A. and the U.S.S.R. were studied in the present work. There was no significant difference between the Finnish and imported rye samples with regard to total dietary fibre content (TDF). Finnish rye was significantly higher in WISDF content and significantly lower in WSDF content compared to imported rye samples. When results from all of the Finnish rye varieties, locations and years were analysed, WISDF had a significant positive correlation with growing time ( r = 0·655***) and with protein content ( r = 0·733***). Significant positive correlations were also found between TDF content and growing time ( r = 0·542***) as well as protein content ( r = 0·681***). On the contrary, the Falling Number showed a negative correlation with WISDF content ( r = −0·590**) and with TDF content ( r = −0·652**). There was also a negative correlation between Falling Number and WSDF content ( r = −0·429*). Environmental factors had an influence on TDF. High precipitation increased TDF content while the mean temperature of the growing period had a negative correlation with it.

Pentosan and β-glucan content of finnish winter rye varieties as compared with rye of six other countries

Pentosan and β-glucan contents of five winter rye varieties were studied at three locations during two years in Finland. The values were compared to values obtained from imported rye samples from Canada, the Federal Republic of Germany, Hungary, Sweden, the U.S.A. and the U.S.S.R. The average pentosan content for different trials (three sites, two years) varied from 9·2 to 11·5 % and β-glucan content from 1·2 to 1·6%. The pentosan content of imported rye samples varied from 6·5 to 8·8 % and β-glucan content from 1·0 to 2·0 %. No significant differences were found in either pentosan or β-glucan contents between different varieties. However, pentosan content correlated highly negatively with thousand grain weight (r = −0·970; P

Natural occurrence ofAlternaria mycotoxins in the grain and chaff of cereals

Samples of wheat and rye heads with evident black discoloration were collected in 1986 and 1987. Four fungal genera colonized such heads:Alternaria, Cladosporium, Drechslera, andEpicoccum. In chaff of wheat (19%) and rye (10%) samples alternariol was present in amounts up to 1.8mg/kg, and alternariol methyl ether up to 0.51 mg/kg. In 1 out of 21 wheat samples alternariol was also present in kernels (0.59mg/kg).