Zearalenone in cereal grains

Zearalenone, a secondary metabolite with estrogenic properties, is produced by severalFusarium species that colonize cereal grains in the field and in storage. Recently, there have been reports of zearalenone contamination in corn, oats, barley, wheat, and grain sorghum. Corn and grain sorghum were examined for contamination due to obvious mold damage. Wheat, corn, and sorghum have been examined to determine the incidence of zearalenone in grains moving through commercial channels and stored on farms and at country elevators. Other grains such as oats and barley were analyzed because of associated estrogenic disturbances in farm animals. Stepsin procedures for the determination of zearalenone are extraction of a representative sample, partial purification of the extract by column chromatography, alkali treatment, or liquid-liquid partitioning, and subsequent measurement of the isolated toxin. Zearalenone is measured in partially purified extracts by thin layer chromatography (TLC), gas liquid chromatography (GLC), and high pressure liquid chromatography (HPLC). Confirmation of zearalenone contamination can be accomplished by gas chromatography-mass spectroscopy (GC-MS). Multitoxin screening procedures have been deveoped for zearalenone in combination with one or more of the following mycotoxins: aflatoxin, T-2 toxin, diacetoxyscirpenol, patulin, ochratoxin, penicillic acid, citrinin, penitrem A, and sterigmatocystin.     

Fatty acid compositions of lipids from corn and grain sorghum kernels

Summary Characteristics and fatty acid compositions of the lipid components of the main fractions (germ, starch, gluten, and fiber) obtained in the wet milling of corn and grain sorghum kernels have been determined. The various lipids exhibited differences in chemical characteristics and fatty acid composition. These differences were found to be similar in both grains. Germ fats were the most unsaturated, contained the least free fatty acids and the least unsaponifiable matter. Starch fats were 70 to 90% free fatty acids and contained large amounts of palmitic acid. Gluten and fiber fats contained up to 32% unsaponifiables and about 20% free fatty acids.     

Nutritional quality of pigeon pea protein, immature and ripe, and its supplementary value for cereals

The purpose of the present research was to determine the differences which could exist between immature and mature pigeon pea in gross chemical composition and protein quality, raw and cooked, as well as their respective supplementary value to rice, and to mature and immature corn and sorghum. The chemical composition data showed only small differences in proximate composition between the mature and immature grain. The cooking process did not affect chemical composition. Based on the FAO/WHO amino acid reference pattern, immature pigeon pea was more deficient in threonine than mature pigeon pea, which was limiting in valine. Both grains were limiting in sulfur amino acids. The protein quality of the immature grain was higher than that of the mature grain, and both responded positively to cooking, suggesting the presence of antiphysiological substances in both. Amino acid supplementation studies demonstrated that both the immature and mature grain responded to methionine addition, the first limiting amino acid, and to tryptophan, the second limiting amino acid. The effects were more marked when samples were cooked. Both types of grains were good supplements to rice, when added in amounts of 10-20%. Mature pigeon peas supplemented relatively well the proteins of sorghum, immature and mature corn, at the 20, 30 and 20% levels, respectively. The differences found could be explained on the basis of the amino acids limiting cereal grains and pigeon peas protein.     

Fatty acids in lipids of maturing wheat

Two varieties of hard red winter wheat were sampled at various stages of maturity. The lipids in those samples were fractionated into free polar, free nonpolar and bound lipids. Fatty acids of those fractions were determined. Major acids present were palmitic, oleic, linoleic and linolenic. Both wheat samples showed similar qualitative, but not quantitative patterns in distribution of fatty acids during maturation. In the free polar lipid fraction, the palmitic acid content decreased with maturation while the linoleic acid content increased. The free nonpolar fractions showed a slight increase in linoleic acid; the concentration of other acids decreased slightly as the wheat matured. The bound lipid fraction showed a marked increase in linoleic acid, accompanied by decreases in the other major fatty acids, especially linolenic. Cooperative investigations of Kansas Agricultural Experiment Station and Crops Research Div., ARS, USDA.     

Lipids of six cultivated barley (Hordeum vulgare L.) varieties

The lipids of representative varieties of 2-row spring, 6-row spring, and 6-row winter-type barleys were studied. Total barley lipids were classified by silicic acid gel column chromatography and separated by thin layer chromatography, and the fatty acid composition was determined by gas liquid chromatography. Total lipid content of the 6 barley varieties ranged from 3.12%–3.56% (dry wt basis). The average values for neutral lipids, glycolipids, and phospholipids were 71, 9, and 20%, respectively. The fatty acid composition of barley was rather typical of plant tissue. The neutral lipids and glycolipids from all the varieties contained a higher percent of linoleic and linolenic (C 18∶2 and C 18∶3) acids than the phospholipid fraction. South Dakota Experiment Station Paper 1248.     

Plant Sterol and Policosanol Characterization of Hexane Extracts from Grain Sorghum, Corn and their DDGS

Plant sterols (PS) and policosanols (PC) have been attributed with plasma cholesterol-lowering properties in humans. Hexane extracts from grain sorghum, corn and their distillers dried grain with solubles (DDGS), an important co-product of ethanol production, contain these health promoting compounds, which could be used to develop health promoting dietary products. However, limited information is currently available regarding optimal methods of extraction and their influence on plant sterol or PC levels and compositions. Therefore, the objective of this study was to quantify lipids, particularly PS and PC extracted from grain sorghum and its DDGS using reflux and Soxtec methods. Corn and its DDGS were also extracted to compare lipid yields and PS/PC compositional profiles in these two related cereals. Intact grains were extracted either as whole or ground kernels. Lipid yields from all the corn sources were typically greater than those obtained from grain sorghum. Lipid yields from DDGS were the highest among all the forms of the grains used whereas corn/sorghum DDGS contained the highest levels of PS and PC, respectively. Additional study demonstrated that hydrolysis (acidic and alkaline) of ground sorghum or sorghum DDGS increased the levels of total extractable plant sterols. Overall, the Soxtec method extracted higher amounts of lipids than the reflux method.     

Proteins in dried distillers' grains with solubles: A review of animal feed value and potential non-food uses

Dried distillers' grains with solubles (DDGS) are the main byproduct from bioethanol production and are commonly used as livestock feed. This work aims to provide an overview of animal feed value (protein and amino acid profiles and protein fractionation approaches) and potential non-food uses of DDGS proteins, particularly those from corn, sorghum, and wheat. Crude protein and amino acids (essential and nonessential) composition vary among different DDGS due to the variation in chemical composition of parent feedstock and processing condition. Extraction or fractionation approaches such as physical/mechanical (sieving and winnowing), chemical (ethanol, acid, and alkaline), and enzymatic (protease) treatments have been explored to isolate specific proteins of corn (zein), sorghum (kafirin), and wheat (gluten protein) from respective DDGS. In addition, valorization of DDGS proteins for biomaterials (biodegradable films and bioadhesives) was evaluated. Due to the heterogeneous nature of DDGS, multi-stream processes with economic and environmental benefits should be taken into consideration before the commercialization of DDGS proteins. This review will benefit future research and development activities on value-added and more specific utilizations of DDGS.     

Lipid composition of oats (Avena sativa L.)

Compositions of lipids extracted from a sample of Hinoat oat by seven solvent systems and that extracted with chloroform/methanol (2:1 v/v) from six selected cultivars representing high and low lipid contents are reported. Lipid components (steryl esters, triglycerides, partial glycerides, free fatty acids, glycolipids and phospholipids) were separated by silicic acid column chromatography and thin layer chromatography and quantitated by GLC analysis of fatty acids and phosphorus determinations. Twelve oat cultivars were examined for the fatty acid composition of lipid extracted with n-hexane. Lipids extracted from Hinoat by different solvent systems ranged from 5.6 to 8.8%. Quantitative distribution of lipid components extracted with chloroform/methanol from six cultivars containing 4.6 to 11.6% lipid showed a significant correlation (γ=0.99) between the total lipid and the neutral lipid content. Phospholipid content was similar in all cultivars, but glycolipids showed a two-fold increase in high lipid oats. Triglycerides contained less palmitic and more oleic acid than the glycolipids or phospholipids. Nine glycolipids and 11 phospholipids have been identified, and the polar lipid composition of Hinoat oat is presented.     

A Comparison of the Levels of Oil,Carotenoids, and Lipolytic Enzyme Activities in Modern Lines and Hybrids of Grain Sorghum

Carotenoids are potentially valuable components in grain sorghum and there is a need to better understand their concentration, composition, and value. Thirteen modern commercial grain sorghum hybrids and five sorghum lines were extracted and analyzed and the levels of oil and carotenoids were compared. The same samples were also evaluated for lipolytic enzyme activity. The oil content in all eighteen samples ranged from 3.21 to 4.29 wt%. Lutein and zeaxanthin were the predominant carotenoids and the levels of total carotenoids ranged from 3.82 to 19.5 ppm in the oil, which was much lower than the levels of total carotenoids in two yellow corn samples (70.8 and 103 ppm). Lipolytic enzyme activity was estimated by storing milled kernel samples for 2 weeks at 25 °C and measuring the levels of total free fatty acids. After 2 weeks, the levels of free fatty acids in the oil of the eighteen sorghum samples ranged from 11.49 and 52.17 wt%, compared to 10.29 and 17.54 wt% in oil from the two corn samples. This new data will be useful for persons using grain sorghum for food, biofuels and other industrial applications. Examples of sorghum genotypes with high and low levels of carotenoids and high and low levels of lipolytic enzymes were both identified.     

Lipid content and fatty acid profiles of various deep-fat fried foods

Forty-one brands of nine different types of snack and convenience foods were purchased from food stores and fast service restaurants in the Sacramento area of California. All samples had been prepared by deep-fat frying. They included potato chips, corn chips, tortilla chips, cheese chips, cheese puffs, cake donuts, french fries, chicken pieces and fish pieces. These samples were analyzed in duplicate for total fat and fatty acid composition. The total lipid content of each type of food varied among different commercial sources; the average percentages were as follows: potato chips, 40; cheese puffs, 38; corn chips, 35; cheese chips, 25; tortilla chips, 24; cake donuts, 22; chicken thighs, 14; french fried potatoes, 14, and fish pieces, 10. The fatty acid profiles of the total lipids in several brands of potato chips were relatively constant. The fatty acid profiles of the total lipids in the corn and cheese snack foods varied widely. Fatty acid compositions of donuts, chicken and fish pieces and french fries were influenced by the amount and fatty acid profile of the lipids in each uncooked food, as well as by the composition of the cooking fat.     

Chemical composition and mineral content of legumes and cereals produced in Northwestern Argentina

Different varieties of bean (Phaseolus vulgaris), corn (Zea mayz), lentil (Lens sp), soya (Glycine max) and wheat (Tricticum sp) were analyzed in order to obtaining data of chemical composition and content of minerals to contribute to the International Food Data System INFOODS in the elaboration of Regional Food Composition Tables and to evaluate the quality of grains. The selected varieties were the ones produced in the northwestern region of Argentina. The beans were divided in five groups, according to their statistical similarity. The pallares variety is the one that presents bigger content of Cu (2.42 mg/100 g), Fe (76.03 mg/100 g) and Zn (6.08 mg/100 g). The samples of corn were divided in three groups, according to their statistical similarity. The leales yellow corn has bigger content of Zn (3.16 mg/100 g) that the other varieties of the region. The 8 rayas white corn is the one that presents bigger content of Fe (11.48 mg/100 g), while the pisingallo yellow corn is that of bigger content of Cu (1.21 mg/100 g).     

Impact of Phenolic Compounds and Related Enzymes in Sorghum Varieties for Resistance and Susceptibility to Biotic and Abiotic Stresses

Contents of phenolic compounds and related enzymes before and after sorghum grain germination were compared between varieties either resistant or susceptible to biotic (sooty stripe, sorghum midge, leaf anthracnose, striga, and grain molds) and abiotic (lodging, drought resistance, and photoperiod sensitivity) stresses. Independent of grain germination, sorghum varieties resistant to biotic and abiotic stresses had on average higher contents of proanthocyanidins (PAs), 3-deoxyanthocyanidins (3-DAs), and flavan-4-ols than susceptible varieties. Results show that content of 3-DAs is a good marker for sorghum resistance to both biotic and abiotic stresses because it correlates with resistance to all stresses except for photoperiod sensitivity. The second good marker for stress resistance is content of PAs. Total phenolic compounds and the activities of related enzymes are not good markers for stress resistance in sorghum grains.     

Quantitative extraction of pecan oil from small samples with supercritical carbon dioxide

A procedure to determine total oil content of pecan was developed for samples weighing 500 and 10 mg by supercritical fluid extraction (SFE) with carbon dioxide as the extraction solvent, and chilled hexane as the trapping solvent. Fatty acid methyl esters (FAMEs) were prepared from the total lipid fraction by using either an aliquot (500 mg starting weight) or the entire extract (10 mg starting weight). Total oil content obtained for either sample size with SFE was similar to that obtained with an organic solvent extraction technique. The fatty acid composition for the total lipid fraction of oils extracted with SFE was the same as for oils extracted with organic solvents, and oil composition did not change during SFE. Both oil yield and fatty acid composition were similar to those reported previously for pecan. Samples could be extracted and placed into FAME-derivatizing reagents in one day, and fatty acid composition of the total lipid fraction could be determined by gas-liquid chromatography the next day. The procedure, as demonstrated for pecan, should be suitable for other oilseeds, especially those containing low amounts of water.     

Changes in Lipid Composition During Dry Grind Ethanol Processing of Corn

During the dry grind ethanol process, ground corn is fermented and the major co-product is a feed called distillers dried grains with solubles (DDGS). This study investigated the changes that occur in the composition of corn oil that can be extracted from various process fractions during the dry grind ethanol process. In the first part of this study, samples of distillers dried grains, thin stillage, condensed distillers solubles (also known as syrup), and DDGS were obtained from 7 dry grind ethanol plants. The levels of deleterious free fatty acids were high (>7%) and those of valuable total phytosterols were also high in all fractions (>2%). In the second part of this study, changes in the content and composition of the fatty acids, phytosterols, tocopherols and tocotrienols were quantitatively analyzed in crude oil samples extracted from nine dry grind process fractions from three commercial ethanol plants. Fatty acid and phytosterol composition remained nearly constant in all nine fractions, although some significant variations in phytosterol composition existed among the fractions. Examination of the tocopherols and tocotrienols revealed that γ-tocopherol was the most abundant tocol in ground corn but an unknown tocol became the predominant tocol after fermentation and persisted in the remaining processing fractions and in the final DDGS product. Overall, the remaining majority of tocols remained relatively unchanged.     

Study of mechanisms of grain dust explosion as affected by particle size and composition.: Part 2. Characterization of particle size and composition of grain dust

Three types of grain dust (corn, wheat, and grain sorghum) and cornstarch (used as a reference) were each divided into varying size fractions (6 to 11) utilizing air and sieve classifications. The particle size distribution and the composition (content of moisture, ash, protein, and starch and fiber) of each size fraction were determined. Dust particles consisting almost entirely of ash material were found to concentrate in specific air-classified size fractions. The total external surface area, the total volume, and the coefficient of variability were calculated from the experimental particle size distribution for each size fraction by utilizing a piecewise log normal approximation. These values were compared with those calculated from the least-squares fitted log normal approximation of the actual distribution.     

Novel soybean oil products for a healthier nutrition – Recent developments,market introduction and targeted commercialization

In recent years, several soybean varieties have been developed with healthier or more functional fatty acid lipid profile. The first of its kind was the high oleic soybean oil developed by ‘DuPont’ using biotechnology enhanced breeding technology. With the increased understanding of the biosynthesis pathways leading to specific fatty acid profiles the development of new varieties was speeded up considerably. Currently, several varieties are going into production in the U.S.A. These varieties have an oil composition, which is considerably reduced in linolenic and/or in saturated fatty acid content, or enhanced in saturated fatty acid composition. The valorisation of these novel varieties requires a full channelling or Identity Preservation throughout the production system. Major processors such as ADM, ‘Bunge’, and ‘Cargill’ have developed specific value chains to capture the extra value of these products. Marketing happens in close cooperation with the seed production site, as well as with main users from the food industry complex.     

Fatty acid composition of rat hearts as influenced by age and dietary fatty acids

Fatty acid composition of neutral and polar lipid fractions from rat hearts was determined in rats of different ages as their diet source changed. Piebald rats were weaned at 21 days and were fed standard lab chow. Lipids from rat hearts, mothers milk and lab chow were purified on a Sephadex G-25 fine column and separated into neutral and polar lipid fractions by silicic acid column chromatography. These lipid fractions were then hydrolyzed and methylated with BF₃ in methanol, prior to gas liquid chromatographic separation on a 1/8 in. × 10 ft aluminum column of 15% EGS on 80–100 mesh acid-washed Chromosorb W. Three major fatty acids in the neutral lipid fraction comprised 72% of total neutral lipid fatty acids from young hearts. At sexual maturity (at least 74 days old) C_18∶1 was the major fatty acid, followed by C_16∶0 and C_18∶0. The same three fatty acids comprised 83% of total polar lipid fatty acids, but C_18∶0 was the major fatty acid, followed by C_16∶0 and C_18∶1. The fatty acid composition of dietary lipids influenced the total neutral lipid fatty acid composition of the rat heart, but had little influence on the fatty acid composition of the polar lipid fraction. Presented in part at the AOCS Meeting, New Orleans, April 1970.     

The structural analysis of wheat flour glycerolipids

The compositions of the fatty acids in the 1, 2 and 3 positions of the principal glycerolipids and their various stereoisomers were determined. Fatty acids in the 1 and 3 positions of triglycerides were similar in composition and less unsaturated than those in the 2 position. Fatty acids in the 1,2-, 1,3- and 2,3-diglycerides were distributed in a pattern which indicated isomerization ofsn-1,2-diacylglycerol. Lysophosphatidyl choline (the principal monoacyl lipid) consisted of about 80% 1-acyl and 20% 2-acyl isomers. The fatty acid compositions indicated that most of the 2-lysophosphatidyl choline was formed by isomerization of 1-lysophosphatidyl choline. Most of the digly cerides and lysophosphatidyl choline were synthesized in the ripening wheat grain. However a small proportion of these partial glycerides and all of the other minor partial glycerides (monoglycerides, digalactosyl monoglycerides) appeared to be the result of limited lipolysis of the corresponding diacyl lipids in the wheat or in the freshly-milled flour. Fatty acids in the 2 position of all the fully acylated glycerides were very similar in composition, but there were considerable differences in the 1 position fatty acids.     

Effects of dietary peanut oil on serum lipoprotein patterns of rats

Oils prepared from two varieties of peanuts and from a hybrid corn having linoleic acid concentrations substantially different from the respective commercial oils were compared with commercial oils for their effects on serum lipids of weanling female rats. In the first experiment, serum lipid patterns appeared to reflect linoleic acid content of the dietary oil. However, with a longer feeding period in the second experiment, serum lipid patterns were determined by the plant source of the dietary oil rather than its linoleic acid content; all peanut oils differed from both corn oils in their physiological effects. Diets containing triglyceride, hydrocarbon and sterol fractions obtained by liquid chromatography of peanut and corn oils were fed to female rats. The data provide no evidence that the hydrocarbon or sterol fractions of peanut oil are responsible for its unusual atherogenicity when fed as the sole fat source or that similar fractions from corn oil are protective against the effects of peanut oil.     

Die Aktivität von Lipoxigenasen in Getreide sowie Möglichkeiten der Enzymhemmung

Activity of Lipoxygenase in Cereals and Possibilities of Enzyme Inhibition In different feed components the activity of the enzyme lipoxigenase was determined. In cereals the enzyme activity predominantly decreases in the following order: barley, wheat, corn, oats and rye. During the malt process the activity of barley lipoxigenases increases to a very high level. During storage ungerminated grains are showing increasing (barley) or decreasing (wheat) variations in enzyme activity. The addition of propionic acid decreases the activity of lipoxigenases in cereals. The peroxide value of added fat in mixed feed was not influenced by lipoxigenases. For wheat products positive relations between the content of crude protein as well as crude fat and the enzyme activity were ascertained. Heat treaments with temperatures exceeding 100% C lowered the lipoxigenase activity to values below 10% of the untreated sample. The usual temperatures during feed processing, e.g. after conditioning and pelleting, are sufficient to inhibit the enzyme activity almost completely.