Improved normal-phase high-performance liquid chromatography procedure for the determination of carotenoids in cereals

Besides the health benefits associated with whole-grain consumption, cereals are recognized sources of health-enhancing bioactive components such as carotenoids, which are a group of yellow pigments involved in the prevention of many degenerative diseases and which have been used for a long time as indicators of the color quality of durum wheat and pasta products. This work reports a fast, sensitive, and selective procedure for the extraction and determination of carotenoids from cereals and cereal byproducts. The method involves sample saponification and extraction followed by normal-phase high-performance liquid chromatography, allowing the separation of the main carotenoids pigments of cereals, especially lutein and zeaxanthin. An application of the established method to various species of cereals and cereal byproducts is also shown. The highest carotenoid levels were found in maize (approximately 11.14 mg/kg of dry weight), which contains high amounts of beta-cryptoxanthin (2.40 mg/kg of dry weight), and, among the cereals considered, has the highest content of zeaxanthin (6.43 mg/kg of dry weight) and alpha+beta-carotene (1.44 mg/kg of dry weight). With the exception of maize, lutein is the main compound found (from 0.23 to 2.65 mg/kg of dry weight in oat and durum wheat, respectively). Moreover, whereas alpha+beta-carotene and zeaxanthin are principally localized in the germ, lutein is equally distributed along the kernel.     

Composition of Functional Lipids in Hulled and Hulless Barley in Fractions Obtained by Scarification and in Barley Oil

Two cultivars of hulled barley (Thoroughbred and Nomini) and two cultivars of hulless barley (Doyce and Merlin) were scarified to abrade the outer layers of hull and pericarp. The resulting scarification fines fractions were evaluated as potential sources of functional lipids (phyto‐sterols, tocopherols, and tocotrienols). The levels of total phytosterols and total tocotrienols in the barley scarification fine fractions were probably not high enough to justify their use as functional foods. However, the levels of total phytosterols and total tocotrienols in the oils extracted from both whole kernels and scarified fines were both sufficiently high to make it reasonable to consider their potential use as new functional oils. Indeed, the levels of total tocotrienols in barley oils (2,911–6,126 mg/kg of oil) are several‐fold higher than those reported in two other oils that are being marketed as high in tocotrienols: palm oil (530 mg/kg) and rice bran oil (770 mg/kg). The levels of total phytosterols in barley oils range from 1.20 to 9.60 g/100 g of oil.     

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.     

Effects of different origins and harvesting time on vitamin C,tocopherols, and tocotrienols in sea buckthorn (Hippophaë rhamnoides) berries

Vitamin C, tocopherols, and tocotrienols in berries of wild and cultivated sea buckthorn (Hippopha? rhamnoides L.) of different origins and harvesting dates were determined with HPLC. Wild berries of subsp. sinensis, native to China, contained 5-10 times more vitamin C in the juice fraction than the berries of subsp. rhamnoides from Europe and subsp. mongolica from Russia (4-13 vs 0.02-2 g/L juice). Genetic background and berry-harvesting date were two primary factors determining the vitamin C content in the berries. Crossing different subspecies influenced the vitamin C content to some extent. For bushes cultivated in southwest Finland, the best berry-harvesting date for high vitamin C content was the end of August. The seeds of subsp. sinensis contained less tocopherols and tocotrienols (average 130 mg/kg) compared with seeds of subsp. rhamnoides (average 290 mg/kg) and mongolica (average 250 mg/kg). The fruit flesh of sinensis berries had contents of tocopherols and tocotrienols 2-3 times higher than those found in the other two subspecies (120 mg/kg vs 40 mg/kg in rhamnoides and 50 mg/kg in mongolica). The fresh whole berries of subsp. sinensis were clearly the best source of total tocopherols and tocotrienols. The total content of tocopherols and tocotrienols in the soft parts of the berries reached the maximum level around early- to mid-September, whereas the content in seeds continued to increase until the end of November. The excellent combination of the highest content of vitamin C and tocopherols and tocotrienols makes the berries of subsp. sinensis an optimal raw material for nutritional investigation as a candidate for functional foods with special antioxidative properties.     

Sterol oxidation in ready-to-eat infant foods during storage

The effect of storage on sterol oxidation of ready-to-eat infant foods was evaluated. Two different liquid infant foods (honey or fruits flavors), prepared with milk and cereals, were stored for 0, 2, 4, 7 and 9 months at 25 degrees C. Sterol oxidation products (SOP) were isolated by cold saponification, purified by silica solid-phase extraction, and analyzed by gas chromatography (GC) and GC-mass spectrometry. beta-Sitosterol was the most representative sterol, followed by cholesterol and campesterol. No significant differences in the total and single SOP content (0.8-1 mg/kg of product) were observed with respect to storage time and type of sample; the main SOP found was 7-ketositosterol (<0.2 mg/kg of product). The extent of stigmasterol oxidation (2.9%) was higher than that of cholesterol (1.9%) and beta-sitosterol (1.4%). The type and quality of raw materials, as well as the processing conditions, seem to greatly influence SOP formation and accumulation in infant foods.     

Optimization and validation of the reversed-phase high-performance liquid chromatography with fluorescence detection method for the separation of tocopherol and tocotrienol isomers in cereals, employing a novel sorbent material

The separation and determination of tocopherols (Ts) and tocotrienols (T3s) by reversed-phase high-performance liquid chromatography with fluorescence detection has been developed and validated after optimization of various chromatographic conditions and other experimental parameters. Analytes were separated on a PerfectSil Target ODS-3 (250 × 4.6 mm, 3 μm) column filled with a novel sorbent material of ultrapure silica gel. The separation of Ts and T3s was optimized in terms of mobile-phase composition and column temperature on the basis of the best compromise among efficiency, resolution, and analysis time. Using a gradient elution of mobile phase composed of isopropanol/water and 7 °C column temperature, a satisfactory resolution was achieved within 62 min. For the quantitative determination, α-T acetate (50 μg/mL) was used as the internal standard. Detection limits ranged from 0.27 μg/mL (γ-T) to 0.76 μg/mL (γ-T3). The validation of the method was examined performing intraday (n = 5) and interday (n = 3) assays and was found to be satisfactory, with high accuracy and precision results. Solid-phase extraction provided high relative extraction recoveries from cereal samples: 87.0% for γ-T3 and 115.5% for δ-T. The method was successfully applied to cereals, such as durum wheat, bread wheat, rice, barley, oat, rye, and corn.     

Contents of phenolic acids, alkyl- and alkenylresorcinols, and avenanthramides in commercial grain products

The contents of free and total phenolic acids and alk(en)ylresorcinols were analyzed in commercial products of eight grains: oat (Avena sativa), wheat (Triticum spp.), rye (Secale cerale), barley (Hordeum vulgare), buckwheat (Fagopyrum esculentum), millet (Panicum miliaceum), rice (Oryza sativa), and corn (Zea mays). Avenanthramides were determined in three oat products. Free phenolic acids, alk(en)ylresorcinols, and avenanthramides were extracted with methanolic acetic acid, 100% methanol, and 80% methanol, respectively, and quantified by HPLC. The contents of total phenolic acids were quantified by HPLC analysis after alkaline and acid hydrolyses. The highest contents of total phenolic acids were in brans of wheat (4527 mg/kg) and rye (4190 mg/kg) and in whole-grain flours of these grains (1342 and 1366 mg/kg, respectively). In other products, the contents varied from 111 mg/kg (white wheat bread) to 765 mg/kg (whole-grain rye bread). Common phenolic acids found in the grain products were ferulic acid (most abundant), ferulic acid dehydrodimers, sinapic acid, and p-coumaric acid. The grain products were found to contain either none or only low amounts of free phenolic acids. The content of avenanthramides in oat flakes (26-27 mg/kg) was about double that found in oat bran (13 mg/kg). The highest contents of alk(en)ylresorcinols were observed in brans of rye (4108 mg/kg) and wheat (3225 mg/kg). In addition, whole-grain rye products (rye bread, rye flour, and whole-wheat flour) contained considerable levels of alk(en)ylresorcinols (524, 927, and 759 mg/kg, respectively).     

Reduced-Oxidized Glutathione Status as a Potential Index of Oxidative Stress in Mature Cereal Grain

The purpose of this study was to examine the reduced and oxidized glutathione status of selected cereal grains as a potential index of balance between oxidative stress and antioxidant systems, and the contribution of reduced glutathione to the total antioxidant status in cereal grain extracts. Wheat cultivars Almari and Henika, barley cultivars Gregor and Mobek, rye cultivar Dañkowskie Złote, oat cultivar Sławko, and buckwheat cultivar Kora were used. Total antioxidant status (TAS) was measured by the ABTS (2,2'-azinobis(3-ethyl-benzothiazoline-6-sulphonate)) method. Contents of total phenolic compounds were also determined. Reduced (GSH) and oxidized glutathione (GSSG) (γ-glutamyl-cysteinyl-glycine) were assayed using the spectrofluorimetric method, and results were confirmed by the enzyme recycling method. Correlation coefficient for the GSH/GSSG ratio was r = 0.79. Correlation between TAS and the total phenolic compound content was r = 0.81. Correlation between GSH/GSSG ratio and TAS values was r= 0.46, depending on the extraction system used. The GSH/GSSG ratio may indicate a hierarchy among different cultivars and variance of cereal grains against damage caused by reactive oxygen species. For the main water-soluble antioxidants, our data indicate a potential hierarchy of resistance in investigated cereals against oxidative stress (buckwheat > wheat > barley ≈ rye > oat). This hierarchy was confirmed by the ability of investigated cereal extracts to scavenge superoxide anion radicals in vitro. The reduced-oxidized glutathione status in different cereal grains can be applied as a potential index of balance between oxidative stress and antioxidant systems.     

Nitrogen effects on yield,beta‐glucan content,and other quality factors of oat and waxy hulless barley

Abstract

Oat (Avena sativa L.) and waxy hulless barley (Hordeum vulgare L.) are important sources of water soluble plant fiber (ß‐glucan) needed in human diets to lower serum cholesterol. Recent studies have shown grain ß‐glucan content is influenced by soil type and environment, however, nitrogen (N) response data for oat and waxy hulless barley are lacking. In this study, we evaluated N effects on grain ß‐glucan content and yield; grain yield, protein content, and test weight; and total dry matter production and N utilization of oat and waxy hulless barley. Rates of applied N were 0, 34, 67, and 101 kg N/ha at three field environments in central Montana during 1989 and 1990. Nitrogen increased all variables except test weight and ß‐glucan content. Waxy hulless barley grain yields fluctuated from 0.82 to 4.11 Mg/ha, ß‐glucan content from 62 to 76 g/kg, and ß‐glucan yields from 51 to 354 kg/ha. Oat yields ranged from 0.85 to 3.83 Mg/ha, ß‐glucan content from 37 to 51 g/kg, and ß‐glucan yields from 35 to 178 kg/ha. Oat ß‐glucan content was positively related to grain protein content, and waxy hulless barley ß‐glucan content was positively related to test weight. ß‐glucan content appeared more related to environmental factors other than N.     

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.     

Quantification of a broad spectrum of lignans in cereals, oilseeds, and nuts

Twenty-four plant lignans were analyzed by high-performance liquid chromatography-tandem mass spectrometry in bran extracts of 16 cereal species, in four nut species, and in two oilseed species (sesame seeds and linseeds). Eighteen of these were lignans previously unidentified in these species, and of these, 16 were identified in the analyzed samples. Four different extraction methods were applied as follows: alkaline extraction, mild acid extraction, a combination of alkaline and mild acid extraction, or accelerated solvent extraction. The extraction method was of great importance for the lignan yield. 7-Hydroxymatairesinol, which has not previously been detected in cereals because of destructive extraction methods, was the dominant lignan in wheat, triticale, oat, barley, millet, corn bran, and amaranth whole grain. Syringaresinol was the other dominant cereal lignan. Wheat and rye bran had the highest lignan content of all cereals; however, linseeds and sesame seeds were by far the most lignan-rich of the studied species.     

Molecular Weight Distribution and (1→3)(1→4)-β-d-Glucan Content of Consecutive Extracts of Various Oat and Barley Cultivars

The content and molecular weight (MW) of β-glucan in extracts from a selection of oat and barley cultivars were compared using flow-injection analysis and high-performance size-exclusion chromatography. From 60 to 75% of the β-glucan was extracted from oat and waxy barley by hot water (90°C) containing heat-stable α-amylase, whereas just 50–55% was extracted from nonwaxy barley. Consecutive extractions with hot water and dimethylsulfoxide (DMSO) extracted 65% (nonwaxy barley) or 75–80% (oat and waxy barley) of the total β-glucan. An extraction with sodium hydroxide and sodium borohydride (NaOH/NaBH₄) increased the percentage of β-glucan extracted to 86–100% but decreased the MW. The MW of β-glucan in the oat cultivars selected was significantly higher than those in the barley cultivars. The β-glucan extracted from the nonwaxy barley cultivars showed significantly higher peak MW than that from the waxy barley cultivars.     

Physiological Responses of Men and Women to Barley and Oat Extracts (Nu‐trimX). I. Breath Hydrogen,Methane, and Gastrointestinal Symptoms

While consumption of diets high in fiber is perceived to result in undesirable gastrointestinal symptoms, the fermentation of undigested carbohydrate in the large intestine may, in fact, have beneficial health effects. In this study, we compared the effects of oats, barley, and their extracts with a glucose control for 24 hr on breath hydrogen and methane production as a marker of colonic fermentation and also assessed gastrointestinal symptoms. Nine men and 11 women (35–57 yr) consumed 1 g/kg of body weight of carbohydrate as glucose or 0.66 g/kg of body weight sugar and 0.33 g/kg of body weight as oat bran, barley flour, oat extract, or barley extract (Nu‐trimX) in a Latin square design. Expired alveolar breath samples were collected after instruction at fasting, 2, 4, 5, 6, 7, 8, 9, 10, and 24 hr after consumption of the test meals. All test meals increased breath hydrogen and methane (both P < 0.0001). Hydrogen, but not methane, responses to barley, oats, and extracts of each were higher (barley > oats, P < 0.05) than responses to glucose (P < 0.0001). Reported gastrointestinal symptoms were not related to specific test meals. Oats and barley, as well as their extracts, can be consumed in greater amounts by Americans to increase soluble fiber and lower fat intake, and thus lower risk factors for chronic disease.     

The effect of zinc (Zn) application on uptake of cadmium (Cd) in some cereal species

It is widely accepted that plants absorb more Cd when they suffer from Zn deficiency, as the Zn deficiency is a critical problem in the world. The effect of increased Cadmium (Cd) application (0 and 15 mg kg^-1 Cd) on growing and Cd concentration in some cereal species was investigated at the increasing rate of Zinc (Zn) applications (0 and 15 mg kg^-1 Zn). The experiment was carried out under greenhouse conditions using a Zn deficient soil. According to the results, that increased Cd applications severely reduced dry matter production of plants. Dry matter production decreased in the following order: bread wheat > oat > maize > barley. These decreases were determined to be statistically significant (P < 0.01). Cd concentration of cereal species increased with the application of increasing rate of Cd, with a similar trend to that of the dry matter. Dry matter production of plants increased and Cd concentrations of plants decreased with the application of increasing rate of Zn. These results show that Cd accumulation of plant increase in Zn deficient soils. Cd accumulation in plants is hindered with the application of Zn.     

Alkylresorcinols in selected Polish rye and wheat cereals and whole-grain cereal products

The alkylresorcinol content and homologue composition in selected Polish rye and wheat cultivars and selected whole-grain cereal products were determined in this study. Cereal grains and whole-grain cereal products were extracted with acetone, whereas bread types were extracted with hot 1-propanol. The average alkylresorcinol content in tested rye (approximately 1100 mg/kg DM) and wheat (approximately 800 mg/kg DM) grains harvested in Poland was within the range previously reported in Swedish and Finnish samples. The total alkylresorcinol content in tested cereal products available on the Polish market varied from very low levels in barley grain-based foods up to 3000 mg/kg DM in wheat bran. The total alkylresorcinol content in 14 bread samples extracted with hot 1-propanol varied from approximately 100 mg/kg DM in whole bread made with honey up to approximately 650 mg/kg DM in whole-rye bread. Calculated ratios of C17:0 to C21:0 homologues, a useful parameter previously used to distinguish between rye and wheat cereals and their derived products, was about 1.2-1.4 in rye products, about 0.2 in wheat products, and varied between 0.2 and 0.6 in cereal-derived products containing a mixture of whole rye and/or wheat. The data set obtained were subsequently compared using cluster and principal component analysis, which allowed the tested cereal products to be classified into two major groups consisting of whole-rye or whole-wheat products, respectively. On the basis of that approach, mixed cereal products containing rye and wheat bran or whole rye and wheat flour were grouped between those two well-defined clusters. Our work not only provides a detailed examination of alkylresorcinols in selected Polish rye and wheat cultivars and selected whole-grain cereal products, but also demonstrates that this type of analysis accompanied by the use of proper statistical algorithms offers an objective way to evaluate the quality of whole-grain rye and/or wheat and their derived products.     

Comparisons of β-Glucan Content of Barley and Oat

The cholesterol-lowering effect of cereal grains has been associated with the soluble fiber component of dietary fiber. β-Glucan is the major soluble fiber component of barley (Hordeum vulgare L.) and oat (Avena sativa L.). Much research has been conducted to determine the β-glucan content of barley and oat genotypes from many different countries. However, genotypes of both crops always were grown in separate experiments, making direct comparisons between the two crops difficult. This study compares in the same experiment the β-glucan content of nine barley and 10 oat genotypes grown at two locations in each of two years (i.e., four environments) in North Dakota. Averaged across genotypes, total β-glucan content of barley and oat groat was similar. Soluble β-glucan content of oat groat was greater than barley, and oat groat had a greater ratio of soluble-to-total β-glucan than barley. The soluble β-glucan content and ratio of soluble to total β-glucan content of the “best” barley genotypes were less than that of oat genotypes with the highest levels of these two traits.     

Physiological Responses of Men and Women to Barley and Oat Extracts (Nu‐trimX). II. Comparison of Glucose and Insulin Responses

This study was designed to compare the glucose, insulin, and glucagon responses to consumption of high‐soluble β‐glucan compounds from oats and barley. After an initial medical evaluation that included blood and urine testing, 11 men and 11 women, nondiabetics, 35–57 years, were selected. Subjects consumed a controlled diet for three days. On the third day of five successive periods, subjects consumed 1 g/kg of body weight of carbohydrate as glucose or 0.66 g/kg of body weight pudding (predominantly sucrose) and 0.33 g/kg of body weight as oat bran, barley flour, oat or barley extract (Nu‐trimX) in a Latin square design. Order of treatment was randomly assigned. Glycemic responses were calculated using the trapezoid method. Data were analyzed using mixed procedure analysis of variance program. Glucose responses to oats, barley, and both extracts, and areas under the curve were significantly lower than responses to the glucose solution (P < 0.0001). Insulin responses for the barley extract were lowest and were significantly lower than for glucose solution. Oat and barley extracts retain the beneficial effects of the grains from which they are extracted. High‐soluble fiber barley is more effective than standard oats. Oat and barley carbohydrate‐based fat substitutes can provide a useful addition to menus to control plasma glucose responses.     

Whole Grains and Digestive Health

Whole grains contain all parts of the grain: the endosperm, germ, and bran. Whole grains are rich in fermentable carbohydrates that reach the gut: dietary fiber, resistant starch, and oligosaccharides. Most research that supports the importance of grains to gut health was conducted with isolated fiber fractions, rather than whole grains. Whole grains are an important source of dietary fiber and grain fibers such as wheat, oats, barley, and rye increase stool weight, speed intestinal transit, get fermented to short chain fatty acids, and modify the gut microflora. Wheat bran is particularly effective in increasing stool weight; wheat bran increases stool weight by a ratio of 5:1. In contrast, many novel fibers that are easily incorporated into beverages and foods increase stool weight only on a ratio of 1:1. In vitro fermentation studies with whole grains have been published. Carbohydrates of oat bran (rich in β‐glucan) were consumed by bacteria faster than those of rye and wheat brans (rich in arabinoxylan). Grain fibers were fermented more slowly than inulin, causing less gas production. Wheat is particularly high in fructo‐oligosaccharides, while wheat germ is high in raffinose oligosaccharides. Some in vivo studies show the prebiotic potential of whole grains. Whole grain breakfast cereal was more effective than wheat bran breakfast cereal as a prebiotic, increasing fecal bifidobacteria and lactobacilli in human subjects. Wheat bran consumption increased stool frequency. Thus, the gut enhancing effects of cereal fibers are well known. Limited data exist that whole grains alter gut health.     

Sap analysis for diagnosis of nitrate accumulation in cereal forages

Abstract

Development of a quantitative, preharvest quiektest for NO₃ levels in cereal forages would improve crop management options to avoid NO₃ toxicity in livestock. Our objective was to determine if concentrations of NO₃ in sap expressed from oat (Avenasativa) and barley (Hordeum vulgare) are correlated with those in dry tissue of simultaneously harvested hay, and to test the reliability of the Cardy portable NO₃ meter for sap analysis in these species. In 1993, whole plant samples were gathered from plots fertilized with variable nitrogen (N) rates at four environments in Montana, and were analyzed for NO₃ concentration in lower‐internode sap and in whole plant dry matter. In 1994 and 1995, the study was repeated at two environments. The sampling technique included three subsamples from each plot for sap analysis, followed immediately by harvest of the entire plot for hay, and further subsampling for dry matter NO₃ analysis after drying. Linear correlations between dry matter and sap NO₃ concentrations were found across species at each environment in 1993 with r values of 0.64 to 0.81. No relationship was established for oat at one environment. Locations differed in the coefficient of correlation, indicating environmental influences on the relationship and/ or variability due to sampling technique. In 1994 and 1995, each species fit a separate linear correlation across site‐years with r values of 0.89 (oat) and 0.87 (barley). The consistency across site‐years (1994–1995) indicates that the variability in preliminary results was overcome with sampling technique. We propose a quantitative quiektest for NO₃ levels in cereal forages using conditional predictions of dry matter NO₃ based on observed values of sap NO₃. Since sap NO₃ readings with the Cardy portable nitrate meter were well correlated (r=0.93) with Accumet ISE readings across critical ranges, quiektest procedures are practical.     

Rapid High‐Performance Liquid Chromatography Determination of Tocopherols and Tocotrienols in Cereals

A rapid normal‐phase high‐performance liquid chromatography (NP‐HPLC) method has been developed for rapid determination of the total content of tocopherols (T) and tocotrienols (T3) in cereals. The new method uses a one‐step extraction followed by NP‐HPLC coupled with a fluorescence detector. The new method provides a baseline separation of the critical peaks of beta‐tocotrienol (β‐T3) and gamma‐tocopherol (γ‐T) within a short time of analysis. The extraction step requires no saponification step or addition of antioxidant. Addition of butylated hydroxytoluene (BHT) had no effect on the stability of vitamin E during sampling. The recovery was 96–100%. The method is demonstrated by successful quantification of vitamin E in barley, wheat, and spelt grains, as well as wheat germ and flours from wheat, spelt, and rye.