Dehydrotriferulic and Dehydrodiferulic Acid Profiles of Cereal and Pseudocereal Flours

Dehydrooligomers of ferulic acid cross‐link polysaccharides such as arabinoxylans and pectic polysaccharides in cereal and certain pseudocereal grains, affecting physiological effects of these fiber components and their physicochemical properties during food processing. An HPLC‐MS method for the analysis of eight diferulic acids and five triferulic acids in low‐lignin samples such as cereal grains and pseudocereals was developed and validated. This method was applied to the analysis of ester‐linked diferulates and triferulates in maize, popcorn, wheat, rye, oats, barley, buckwheat, and amaranth, giving a complete profile of this set of diferulates and triferulates in cereals and pseudocereals. Triferulic acid contents of the cereal flours are roughly 1/10 of the diferulic acid contents, ranging between 23 (oats) and 161 (popcorn) μg/g of flour, with lower amounts for the pseudocereal flours (1–3 μg/g of flour). Dominating trimers are either the 5‐5/8‐O‐4‐ and/or the 8‐O‐4/8‐O‐4‐regioisomers with lower proportions of 8‐8cyclic/8‐O‐4‐, 8‐5noncyclic/8‐O‐4‐, and 8‐5noncyclic/5‐5‐triferulic acids. A unique diferulate pattern was found for buckwheat, with more than 90% of the dimers being 8‐5‐coupled. Amaranth contains an unusually high proportion of 8‐8cyclic‐diferulate, with 27% of the total dimers, whereas oats and barley show comparably high proportions (23%) of the 8‐8tetrahydrofuran diferulate.     

REVIEW: Effects of Germination on the Nutritional Profile of Gluten‐Free Cereals and Pseudocereals: A Review

There are a growing number of individuals diagnosed with food allergies and intolerances. Gluten, in particular, is avoided by many individuals because of celiac disease, gluten intolerance, and gluten ataxia. Individuals with allergies, intolerances, or both follow strict diets, but there is concern that these individuals may be at risk of several nutrient deficiencies, including decreased calcium, iron, B vitamins, and fiber. To prevent deficiencies, alternative sources of these nutrients must be provided. Gluten‐free cereals and pseudocereals such as amaranth, buckwheat, corn, millet, rice, sorghum, and quinoa can be excellent sources of vitamins, minerals, fiber, and other important nutrients. Germination of these edible seeds has been shown to further increase nutrient content and to reduce antinutrients. Their use to naturally fortify and enrich gluten‐free foods has great potential. Although there are many benefits to germinated seeds in food, more research must be done to improve texture and sensory properties to gain wider consumer acceptance. A review of germination of gluten‐free cereals and pseudocereals and its effect on their nutritional profile is presented.     

Identification and differences of total proteins and their soluble fractions in some pseudocereals based on electrophoretic patterns

Genetic diversity and relationships of 11 species and cultivars belonging to different Angiosperms families were examined using sodium dodecyl sulfate seed protein markers. The protein was resolved into 36 bands (for soybean), 41 (for quinoa), 35 (for buckwheat), and 28 to 39 bands of Amaranth species, respectively. All species and cultivars can be distinguished from each other. Soybean, quinoa, and buckwheat species had a characteristic protein pattern showing a high degree of polymorphism. The protein patterns of soybean were considerably different from other species. Amaranth species had similar seed protein electrophoretic profile. The similarity coefficients calculated on the basis of presence and absence of bands ranged from 0.08 to 0.97. Following the UPGMA algorithm of similarity coefficients, the examined species and varieties could be clustered into two similarity groups. Our results did not confirm the Tachtadzjan hypothesis that Polygonales (e.g., buckwheat) and Caryophyllales (e.g., quinoa and amaranth) are closely related. Our data rather indicate occurrence of significant genetic distance (similarity coefficients 0.05-0.10). Also, it is doubtful that amaranth and quinoa species are also closely related (similarity coefficients varied from 0.16 to 0.25). It seems that soybean, quinoa, buckwheat, and amaranth (as a genus) can be considered as phylogenetic distant taxa. Differences and similarities in the secondary structure were observed by circular dichroism spectra. Some similarity was found between these plants in their soluble protein fractions and amino acid composition. These plants can be a substitution of each other as well as for cereals.     

Genotypic Variation in Nutritional Composition of Buckwheat Groats and Husks

Buckwheat (Fagopyrum esculentum), a highly nutritious pseudocereal rich in bioactive compounds, is principally cultivated in central and eastern European countries. Buckwheat groats and husks of 10 cultivars were subjected to nutritional composition analysis and in vitro starch digestibility determination. Significant genetic variation was detected in buckwheat groats for 1,000‐kernel weight (16.5–39.8 g), protein content (10.2–17.9%), soluble dietary fiber (1.4–3.4%), insoluble dietary fiber (2.3–8.6%), total dietary fiber (3.6–10.6%), free phenolics (4.5–17.1 mg of gallic acid equivalent [GA]/g), and total phenolics content (6.8–20.7 mg of GA/g). The buckwheat husks exhibited large differences between cultivars in protein content (3.0–6.5%), bound phenolics (6.7–26.1 mg of GA/g), and total phenolics content (32.4–58.6 mg of GA/g), which was 1.5–8 times higher than in the groat. Cooked and cooled buckwheat groats exhibited lower starch digestibility and greater resistant starch content than raw buckwheat groats. Buckwheat cultivars with unique nutritional composition, such as Co901 and Ta‐1, were identified for future breeding.     

Tocopherol and Tocotrienol Content in Commercial Wheat Mill Streams

The content of tocopherols and tocotrienols, collectively known as vitamin E (tocols), was determined in fractions of roller‐milled wheat grains. The results showed that vitamin E components are present in all major flour fractions of wheat, but that the vitamin E content and composition differed significantly between fractions. The total content of vitamin E, calculated as alpha‐tocopherol equivalents, changed from 16.1 mg α‐TE/g in wheat grain to 12.2 mg α‐TE/g in roller‐milled wheat flour. The germ fraction had the highest content of tocopherols, and the content of α‐tocopherol (195.2 μg/g) was 16 times higher (on average) than in any other fraction. The content of tocotrienols was distributed more uniform in the wheat grain with the highest content in the bran fractions, and the content of β‐tocotrienol was higher than the content of α‐tocopherol in all milling fractions except the wheat germ. The content of β‐tocotrienol was 24.1 μg/g in wheat grain, 25.3–31.0 μg/g in the bran fractions, and 14.3–21.9 μg/g in the fractions of endosperm. Overall, germ and fine bran fractions represent good sources of vitamin E and might be used in breadmaking.     

Chemical and Physical Characteristics of Proso Millet (Panicum miliaceum)‐Based Products

Celiac disease and gluten sensitivities, as well as obesity and overweight‐related disorders, have led to the investigation of gluten‐free grains and development of new food products. To address this, refined proso millet and refined corn (control), both gluten‐free grains, were used to produce four different product types (muffin, couscous, extruded snack, and porridge). The products contained four different grain combinations (100% proso millet, 75% proso millet/25% corn, 25% proso millet/75% corn, and 100% corn). All products were evaluated for their nutritional composition, in vitro starch digestibility, and expected glycemic index (eGI). Products made with refined proso millet had increased protein (7.6–11.3%), lipid (1.2–6.1%), fiber (7.0–8.8%), and phenolic content (323.5–425 μg/g) compared with those incorporating corn flour (2.5–9.0%, 0.8–4.0%, 2.1–4.1%, and 213–315 μg/g, respectively). As the proso millet content increased, the eGI decreased significantly (P < 0.05). Products made from refined proso millet appear to be good candidates for producing low‐GI, gluten‐free foods.     

Aroma Compounds in Buckwheat (Fagopyrum esculentum Moench) Groats,Flour, Bran,and Husk

Buckwheat is a pseudocereal with a strong characteristic aroma. Compounds responsible for the aroma of buckwheat groats were recently identified, but the distribution of aromatic compounds between different fractions of the buckwheat kernel (flour, bran, and husk) is not yet known. In this study, the composition of aromatic compounds in buckwheat seed fractions was investigated and compared to the composition of aromatic compounds in groats produced from the same batch of buckwheat seeds. Volatiles from each sample were extracted with simultaneous distillation/extraction with a Likens‐Nickerson apparatus. Extracts were analyzed by gas chromatography coupled with mass spectrometry (GC‐MS) with electron ionization. Apart from the aroma molecules present in all fractions, compounds that are present only in flour or bran, but not in groats, were also found. Furthermore, some compounds were identified only in buckwheat groats but not in buckwheat flour or bran [octanal, (E,E)‐2,4‐heptadienal, (E)‐2‐decenal, and (E,E)‐2,4‐decadienal], others were identified only in husks [(E)‐2‐hexenal, heptanal, (E,E)‐2,4‐hexadienal, phenylacetaldehyde, and alpha‐bisabolol].     

Antioxidant activity of grains

Epidemiological studies have shown that consumption of whole grains and grain-based products is associated with reduced risk of chronic diseases. The health benefits of whole grains are attributed in part to their unique phytochemical composition. However, the phytochemical contents in grains have been commonly underestimated in the literature, because bound phytochemicals were not included. This study was designed to investigate the complete phytochemical profiles in free, soluble conjugated, and insoluble bound forms, as well as their antioxidant activities in uncooked whole grains. Corn had the highest total phenolic content (15.55 +/- 0.60 micromol of gallic acid equiv/g of grain) of the grains tested, followed by wheat (7.99 +/- 0.39 micromol of gallic acid equiv/g of grain), oats (6.53 +/- 0.19 micromol of gallic acid equiv/g of grain), and rice (5.56 +/- 0.17 micromol of gallic acid equiv/g of grain). The major portion of phenolics in grains existed in the bound form (85% in corn, 75% in oats and wheat, and 62% in rice), although free phenolics were frequently reported in the literature. Ferulic acid was the major phenolic compound in grains tested, with free, soluble-conjugated, and bound ferulic acids present in the ratio 0.1:1:100. Corn had the highest total antioxidant activity (181.42 +/- 0.86 micromol of vitamin C equiv/g of grain), followed by wheat (76.70 +/- 1.38 micromol of vitamin C equiv/g of grain), oats (74.67 +/- 1.49 micromol of vitamin C equiv/g of grain), and rice (55.77 +/- 1.62 micromol of vitamin C equiv/g of grain). Bound phytochemicals were the major contributors to the total antioxidant activity: 90% in wheat, 87% in corn, 71% in rice, and 58% in oats. Bound phytochemicals could survive stomach and intestinal digestion to reach the colon. This may partly explain the mechanism of grain consumption in the prevention of colon cancer, other digestive cancers, breast cancer, and prostate cancer, which is supported by epidemiological studies.     

REVIEW: Wild Rice: Both an Ancient Grain and a Whole Grain

Wild rice (Zizania spp.) grows in shallow waters of North America and is distinct from brown and white rice (Oryza spp.). The recent trends toward gluten‐free foods and ancient grains present an opportunity for increased interest in the health benefits of wild rice. Wild rice is classified as a whole grain and typically contains 75% carbohydrate, 6.2% dietary fiber, 14.7% protein, and 1.1% lipids. Wild rice is a good source of dietary fiber and has nearly double the amount of protein of white rice. The lipid content is low; however, most of the lipids are essential omega‐6 (35.0–37.8%) and omega‐3 (20.0–31.5%) fatty acids. In addition to macronutrient content, wild rice contains phytosterol levels several times higher than white rice. Furthermore, the antioxidant activity of wild rice is 10–15 times higher than white rice. A series of rat studies in which wild rice was added to a high fat, high cholesterol diet found significant attenuation of serum free fatty acids, total cholesterol, and triglyceride levels while maintaining higher high‐density lipoprotein levels compared with a control diet. The exact explanation of the protective mechanism of wild rice is uncertain, but the dietary fiber, phytosterol, or antioxidant capacity of wild rice may be the reason for it. Current interest in whole grains and gluten‐free diets, as well as antioxidants and phytochemicals, makes wild rice an attractive grain addition to the diet.     

不同种类及加工方式对杂粮酸奶体外抗氧化活性的比较

为探究杂粮品种及加工方式对杂粮酸奶体外抗氧化活性的影响,选择小米、黄米、燕麦、藜麦、糙米、荞麦、高粱米7种杂粮为原料,经过蒸制、煮制、打浆3种常见加工方式,比较其多酚含量及抗氧化活性,对特性较好的杂粮经恰当处理后与牛奶共发酵制备酸奶,研究该杂粮酸奶的多酚含量及抗氧化活性,开发具备抗氧化活性的杂粮酸奶。结果表明,7种杂粮的之间的抗氧化能力存在显著（P<0.05）差异,采用抗氧化综合（antioxidant potency composite,APC）指数法评定杂粮的抗氧化活性,发现抗氧化活性最高的杂粮为荞麦。进一步对荞麦进行加工处理,发现蒸制处理后其抗氧化活性优于煮制和打浆。将蒸制的荞麦与牛奶混合制备酸奶,制成的荞麦酸奶总酚含量为52.85 mg/100g,是普通酸奶的5.16倍;且其抗氧化能力显著高于普通酸奶（P<0.05）。该研究为功能性杂粮酸奶的开发提供借鉴。     

Formation of Oligosaccharides and Polysaccharides by Lactobacillus reuteri LTH5448 and Weissella cibaria 10M in Sorghum Sourdoughs

Gluten‐free breads, which are composed of gluten‐free flours, starch, and hydrocolloids, differ from wheat and rye breads in relation to texture, volume, and crumb structure. Moreover, the dietary fiber content is lower compared with wheat or rye breads. Cereal isolates of lactic acid bacteria frequently produce oligo‐ and homopolysaccharides from sucrose, which can improve the nutritional and technological properties of gluten‐free breads as prebiotic carbohydrates and hydrocolloids, respectively. Sorghum sourdough was fermented with Lactobacillus reuteri LTH5448 or Weissella cibaria 10M, which synthesize fructooligosaccharides (FOS) and levan, and isomaltooligosaccharides and dextran, respectively. The gluten‐free bread was produced with 14% sourdough addition. L. reuteri LTH5448 formed FOS and 1.5 g of levan/kg DM in quinoa sourdoughs. FOS were digested by the baker's yeast during proofing, and the levan could be qualitatively detected in the bread. W. cibaria 10M produced >60 g of isomaltooligosaccharides/kg DM and 0.6 g of dextran/kg DM, which could still be detected in the bread. Breads prepared with W. cibaria 10M were less firm compared with breads prepared with L. reuteri LTH5448 or a FOS and levan‐negative mutant of L. reuteri LTH5448. The addition of sourdoughs fermented with oligo‐ and polysaccharide forming starter cultures can increase the content of prebiotic oligosaccharides in gluten‐free breads.     

Accumulation of High‐Molecular‐Weight Glutenin Subunits in Superior and Inferior Grains of a Winter Wheat,Yangmai 158

The difference in accumulation of high‐molecular‐weight glutenin subunits (HMW‐GS) in superior (basal) and inferior (distal) grains results in the nonuniformity of grain quality in a winter wheat (Triticum aestivum L. ‘Yangmai 158’). The HMW‐GS accumulation and glutenin macropolymer (GMP) content were studied in superior and inferior grains during the grain‐filling period. Compared with inferior grains, HMW‐GS was formed earlier and total accumulation amount was higher in superior grains. The total HMW‐GS content was higher in superior grain than inferior grain, except at maturity. For individual HMW‐GS types, the accumulation and content of subunit 7 were the highest, followed by subunit 12, and those of subunit 8 were the lowest, followed by subunit 2 in superior grain. In contrast, the accumulation and content of subunit 7 at maturity were significantly higher than subunit 8 but similar between subunit 2 and subunit 12 in inferior grain. Moreover, the accumulation of subunit 7 and 12 in superior grain was significantly higher than in inferior grain. However, compared with the inferior grain, the GMP accumulation was higher but content was lower in superior grain at maturity.     

Comparison of protein quality and mineral element concentrations in grain of spelt (Triticum spelta L.) and common wheat (Triticum aestivum L.)

The cultivation of Triticum spelta (spelt) has no tradition in Hungary. In recent years the interest towards this old species renewed in many countries. This high‐nutritional cereal, which has a high ash and fibre content, can be used in many health‐oriented grain‐based food products. Therefore, field experiments have been conducted for some years to test the performance of this species under home growing conditions. Here we report the results of analyses for some important quality parameters of grain samples from the 1996/97 season in comparison with those of older and new home‐grown bread wheat cultivars. Three common wheat cultivars and one advanced spelt line were grown on small plots fertilised with an NPK dose necessary to reach the highest yield and quality. Spikes were sampled weekly from the time of 70–77% grain moisture to full ripening. The grains were analysed for ash, N, P and K content and amino acid composition. Concentrations of 16 other macro + micro elements and in the ripe grains, baking quality parameters were also assessed. The grain development of spelt showed a remarkable time‐lag compared to that of the common wheat cultivars. However, the highest thousand‐grain‐masses, ash, N, and P concentrations were measured in this cultivar after milk ripening. The grains of spelt contained the macro‐nutrient Mg and four micro‐nutrients (Zn, Mn, Fe, Cu) in higher concentrations compared to those of the common wheat varieties. The total and essential amino acid concentrations measured in the ripe grains of spelt were also remarkably higher.

Although its wet gluten content (47.5%) was considerably higher than that of the bread wheat cultivars, its breadmaking quality was poor.     

Textural Comparisons of Gluten‐Free and Wheat‐Based Doughs,Batters, and Breads

Studies were conducted with two newly developed gluten‐free bread recipes. One was based on corn starch (relative amount 54), brown rice (25), soya (12.5), and buckwheat flour (8.5), while the other contained brown rice flour (50), skim milk powder (37.5), whole egg (30), potato (25), and corn starch (12.5), and soya flour (12.5). The hydrocolloids used were xanthan gum (1.25) and xanthan (0.9) plus konjac gum (1.5), respectively. Wheat bread and gluten‐free bread made from commercial flour mix were included for comparison. Baking tests showed that wheat and the bread made from the commercial flour mix yielded significantly higher loaf volumes (P < 0.01). All the gluten‐free breads were brittle after two days of storage, detectable by the occurrence of fracture, and the decrease in springiness (P < 0.01), cohesiveness (P < 0.01), and resilience (P < 0.01) derived from texture profile analysis. However, these changes were generally less pronounced for the dairy‐based gluten‐free bread, indicating a better keeping quality. Confocal laser‐scanning microscopy showed that the dairy‐based gluten‐free bread crumb contained network‐like structures resembling the gluten network in wheat bread crumb. It was concluded that the formation of a continuous protein phase is critical for an improved keeping quality of gluten‐free bread.     

Free and Bound Phenolic Acids and Total Phenolics in Black,Blue, and Yellow Barley and Their Contribution to Free Radical Scavenging Capacity

Barley is considered a healthy food because of its high content of β‐glucan and phenolic antioxidants. In the current study, 28 black, blue, and yellow barleys were investigated in terms of their composition of free and bound phenolic acids and 2,2‐diphenyl‐1‐picrylhydrazyl radical scavenging capacity. Free phenolics were based on aqueous methanol extraction, whereas bound phenolics were extracted following alkaline hydrolysis. Phenolics were then separated and quantified by liquid chromatography and the Folin–Ciocalteu method. Significant differences were observed between the three barley color groups, and within each color group a wide range of phenolics concentrations existed. Ferulic acid was the predominant phenolic acid in free and bound extracts, followed by p‐coumaric acid in all the barleys investigated. Total phenols content and individual phenolic acids strongly correlated with free radical scavenging capacity of barley. Black and blue barley were found to be related and distinct from yellow barley. The results showed significant variations in phenolics among barleys, with a potential for the development of barley grains with high content of phenolic compounds as antioxidant potential.     

不同粒色藜麦挤压面条品质特性分析

为了探究不同粒色藜麦挤压面条品质特性的差异及机理,该研究对比分析了不同粒色藜麦粉的基础组分、糊化特性、挤压面条微观结构、蒸煮品质、活性成分及淀粉体外消化特性的差异。结果表明：白藜麦粉中淀粉含量最高,糊化后峰值黏度、最终黏度和回生值也最高。红、黑藜麦粉及挤压面条中的多酚、黄酮含量及抗氧化活性显著高于白藜麦粉和挤压面条。挤压后,淀粉结晶度均下降,白藜麦面条中淀粉的结晶度最高。红（2.25 min）、黑藜麦（2.75 min）面条的蒸煮时间短,但蒸煮品质显著低于白藜麦面条（P < 0.05）。扫描电镜显示白藜麦面条淀粉凝胶网络结构更加连续致密,导致其淀粉水解率和预计升糖指数显著低于红、黑藜麦面条（P < 0.05）。该研究为高品质藜麦面条的生产加工提供理论和技术参考。     

Compliance with Gluten‐Free Labelling Regulation in the Brazilian Food Industry

Gluten is an important protein complex for baking products found in wheat, rye, barley, and some oat varieties. However, some people need to avoid these grains and their products because they result in gluten‐related disorders. The only treatment for these individuals is to engage in a gluten‐free diet. The objective of this work was to verify if the gluten content of several commercial food products sold in Brazil complied with their labeling. The Méndez ELISA R5 sandwich method was used to analyze 437 samples, and of these, 70% were labeled as gluten‐free, 26% as containing gluten, and 4% not labeled in relation to gluten. The results indicated that 89% of the products labeled as gluten‐free were correctly labeled and 11% were not, which represented a risk for celiac people.     

Distribution of Vitamin E, squalene, epicatechin, and rutin in common buckwheat plants (Fagopyrum esculentum Moench)

Buckwheat leaves and young parts of the plant are consumed in some countries as a vegetable. Green flour, obtained by milling of the dried plants, is used as a natural food colorant. The distribution of vitamin E, squalene, epicatechin, and rutin (as the most important antioxidants) within buckwheat plants, as well as changes of their content within leaves during the growing season, were determined by GC-MS and HPLC analyses. alpha-Tocopherol was found as the main component of vitamin E in all parts of the plant; epicatechin and squalene were also detected. For the use of buckwheat as an antioxidant source in the human diet, the most suitable part of the plants seems to be the leaves and the flowers at the stage of full flowering due to the considerable amounts of rutin and epicatechin. alpha-Tocopherol content correlates positively with temperature, drought, and duration of solar radiation. Certain differences appear among varieties of buckwheat, especially in their squalene and rutin contents.