Quantitative and qualitative study of spelt and wheat fibres in varying milling fractions

The fibre composition of four spelt genotypes and of three wheat genotypes was studied on three grindings: bran, whole bare grains flour for all genotypes, and whole hulled grains flour for spelt only. Insoluble fibre and soluble fibre contents were measured after removal of proteins, starch and ashes from the sample (Lee, Prosky, & De Vries, 1992). Cellulose, hemicellulose and lignin contents were measured according to the same principles with different chemical degradations of the sample (Van Soest & Wine, 1967). Spelt and wheat bran and whole grain flour displayed significant statistical differences for hemicellulose and cellulose contents. Variability amongst the spelt genotypes was much higher than amongst the wheat genotypes. The study also highlighted the special profile of the true baking variety Ressac and the richness in fibres of the landrace 140. Finally, various methods of measurement were compared and a combination of these methods was proposed for cereal grains dietary fibre analysis.     

The nutritional property of endosperm starch and its contribution to the health benefits of whole grain foods

Purported health benefits of whole grain foods in lowering risk of obesity, type 2 diabetes, cardiovascular disease, and cancer are supported by epidemiological studies and scientific researches. Bioactive components including dietary fibers, phytochemicals, and various micronutrients present in the bran and germ are commonly considered as the basis for such benefits. Endosperm starch, as the major constituent of whole grains providing glucose to the body, has been less investigated regarding its nutritional property and contribution to the value of whole grain foods. Nutritional quality of starch is associated with its rate of digestion and glucose absorption. In whole grain foods, starch digestion and glucose delivery may vary depending on the form in which the food is delivered, some with starch being rapidly and others slowly digested. Furthermore, there are other inherent factors in whole grain products, such as phenolic compounds and dietary fibers, that may moderate glycemic profiles. A good understanding of the nutritional properties of whole grain starch is important to the development of food processing technologies to maximize their health benefits.     

Wheat bran-based biorefinery 1: Composition of wheat bran and strategies of functionalization

Wheat, together with maize and rice, accounts to about 90% of the world's cereal production. During the milling process, wheat bran, besides other valuable compounds such as wheat germ and parts of the endosperm, remains as major by-product. Wheat bran is composed of various histological cell layers, called the pericarp, testa, hyaline and aleurone layer and its weight ratio to milled wheat is about 25%. Annually, over 650 million tons of wheat are produced in the world, of which more than 69% are used for food. The thereby accruing biomass of wheat bran can be estimated as 150 million tons, which are basically used in the feed industry. Even if numerous studies have investigated potential health benefits of consuming more whole grain foods, the addition of bran to existing food systems may confer difficulties in terms of processing, nutrition or sensory acceptance by consumers. This review will summarize state-of-the-art technological approaches such as mechanical, thermal or enzymatic treatment used to modify the functional properties of wheat bran and coincidently describe the impact on the food system.     

Total phenolic compounds and antioxidant capacity of wheat graded flours by polishing method

The graded flour fractions, which were milled from whole wheat grain from outer to inner parts without removal of germ and bran, are rich in dietary fibers and minerals, the sources of nutrition for human beings. In this study, the whole waxy wheat was milled into five fractions using the gradual milling method and the phenolic contents and antioxidant capacity of these flours were investigated. The total phenolic and flavonoid contents of free and bound phenolic extracts gradually increased in the order from the inner to the outer fractions. The flours milled from the outer parts of grain contained significantly higher amount of phenolics and exhibited significantly higher antioxidant capacity than did the whole grain. Likewise, the inner flour fractions milled from mostly endosperm part had significantly higher amount of phenolics and exhibited significantly higher antioxidant capacity than did the white flour, which was milled by a conventional milling method. Thus, the graded flours from whole waxy wheat should be encouraged to be used for processing whole-grain foods to improve both qualities of end-use products and health benefits.     

Wheat aleurone: separation, composition, health aspects, and potential food use

Over the last three decades substantial attention has been given to the role of dietary fiber in health and disease, in particular diabetes, cardiovascular disease, intestinal health, and some types of cancer. As a result the food industry started to add back fiber to refined foods and develop fiber rich foods. Scientists suggested that whole grain foods are superior to foods enriched with fibers obtained/synthesized using enzyme treatment, and thermal or chemical processing because the content of bioactive components and micronutrients in whole grain is more abundant. This triggered interest in how to isolate the micronutrient rich aleurone fiber fraction from wheat. Aleurone is a single cell layer at the inner site of the bran. It contains most of the minerals, vitamins, phenolic antioxidants, and lignans of the wheat grain. Novel milling and dry-fractionation techniques have recently allowed for full-scale separation of aleurone cells from the other layers of wheat bran, yielding a fiber rich concentrate which potentially contains many of the "whole grain kernel bioactives," which recently have been used in a variety of studies. The present review highlights available data on aleurone isolation, composition, intestinal physiology, and its metabolism and potential health benefits as well as its use in food.     

Pasting properties of starch and protein in selected cereals and quality of their food products

In an attempt to improve intake of dietary fibre and antioxidants and quality of whole grain products, whole grain meals from barley, millet, rye and sorghum were evaluated individually and in blends with wheat flour in terms of starch pasting properties and protein heat damage, during cycles of heating and cooling in RVA tests. The whole grain meals were blended with either hard or soft wheat flour and processed into bread, cake, cookie or snack products. The products were then evaluated with regard to physical properties and acceptability. Significant differences were observed between cereals in starch peak, breakdown and setback viscosities as well as in protein peak viscosity. The results showed that RVA could be used to help formulate cereal blends with certain pasting properties. Substitution of wheat flour, with 15% of barley, rye, millet or sorghum whole grain, did not have significant detrimental effects on physical properties or acceptability of pita bread. Additionally, replacement of wheat flour with up to 30% of barley, rye, millet or sorghum whole grain meal had no significant effects on quality of cakes or cookies. A multigrain snack-like food was also developed as a healthy product and was highly acceptable in a sensory test. The developed product would help enhance consumption of whole grain foods, resulting in improved intake of fibre and health-enhancing components.     

Effect of adding wheat bran and germ fractions on the chemical composition of high-fiber toast bread

The effect of the type of bran, level of addition, particle size and addition of wheat germ on the chemical composition of high-fiber toast bread was investigated. The bran and germ fractions were found to be high in ash, protein, fat and total dietary fiber contents. The wheat germ had a protein content of 27.88% compared with 11.35, 12.69 and 15.76% for white flour, whole wheat flour and red fine bran, respectively. The chemical composition of high-fiber breads, in terms of minerals, protein, fat and dietary fiber contents, was found to be far superior than that of the whole wheat flour (control) bread sample. Considering these results, it can be concluded that high-fiber toast bread, with lighter crumb color and improved sensory and nutritional qualities than the whole wheat flour bread, can be produced using white flour, and equal proportions of coarse and fine bran at 20%, germ at 7.5%, and sodium stearoyl-2-lactylate at 0.5% levels.     

A comprehensive review of wheat phytochemicals: From farm to fork and beyond

The health benefits of whole wheat consumption can be partially attributed to wheat's phytochemicals, including phenolic acids, flavonoids, alkylresorcinols, carotenoids, phytosterols, tocopherols, and tocotrienols. It is of increasing interest to produce whole wheat products that are rich in bioactive phytochemicals. This review provides the fundamentals of the chemistry, extraction, and occurrence of wheat phytochemicals and includes critical discussion of several long-lasting issues: (1) the commonly used nomenclature on distribution of wheat phenolic acids, namely, soluble-free, soluble-conjugated, and insoluble-bound phenolic acids; (2) different extraction protocols for wheat phytochemicals; and (3) the chemistry and application of in vitro antioxidant assays. This review further discusses recent advances on the effects of genotypes, environments, field management, and processing techniques including ultrafine grinding, germination, fermentation, enzymatic treatments, thermal treatments, and food processing. These results need to be interpreted with care due to varied sample preparation protocols and limitations of in vitro assays. The bioaccessibility, bioavailability, metabolism, and potential health benefits of wheat phytochemicals are also reviewed. This comprehensive and critical review will benefit scientific researchers in the field of bioactive compounds of cereal grains and also those in the cereal food industry to produce high-quality functional foods.     

Application of common wheat bran for the industrial production of high‐fibre pasta

The study was conducted on the effect of the addition of common wheat bran on the chemical composition, physical properties, cooking quality and sensory traits of durum wheat pasta. The pasta was produced on an industrial scale, applying an addition of common wheat bran at doses ranging from 20 to 40%. The products obtained were compared to the pasta from whole‐grain durum wheat flour, produced under identical conditions and with commercially available whole‐grain durum wheat pasta. The increase in the content of wheat bran in the pasta caused a significant increase (Duncan test, P ≤ 0.05) of the content of protein, lipids, ash and total dietary fibre (TDF). The application of 25–30% addition of common wheat bran allowed obtaining the products which are as rich in dietary fibre as the pasta prepared at the same technological parameters from whole‐grain durum flour. The pasta containing up to 30% of bran was characterised with lower losses of dry mass and higher resistance to overcooking, in comparison with the pasta made of whole‐grain durum. Simultaneously, the products had very good sensory quality.     

The Beneficial Use of Cereal and Cereal Components in Probiotic Foods

Cereals and cereal components can be used as fermentation substrates for probiotic organisms imparting prebiotic effects. Consumer interest in healthy functional foods has resulted in the need for food products with versatile health-benefiting properties. The conventional choice for probiotic food applications has been dairy-based products, but whole grain-based probiotic functional foods have debuted in Japan and Europe. In the US, pro- and prebiotics are mainly marketed as dietary supplements, but are moving towards inclusion in the diet as mainstream foods. Cereal constituents, such as wheat bran-based ingredients fermented with probiotics, would enhance consumer health with the benefits of probiotics, bran fiber, and healthful bioactive components.     

Composition and functionality of wheat bran and its application in some cereal food products

Production of wheat bran (WB) for human consumption is estimated to be about 90 million tonnes per year. WB is a cheap and abundant source of dietary fibre which has been linked to improved bowel health and possible prevention of some diseases such as colon cancer. It also contains minerals, vitamins and bioactive compounds such as phenolic acids, arabinoxylans, alkylresorcinol and phytosterols. These compounds have been suggested as an aid in prevention of noncommunicable diseases such as cardiovascular disease. This article discusses WB extraction, its nutritional properties, potential health benefits, effects on quality and sensory properties of some cereal foods, and its application in some baked products as well as in fried cereal snacks, as an additive for oil reduction and fibre enrichment.     

Dough properties and breadmaking qualities of whole waxy wheat flour and effects of additional enzymes

BACKGROUND: Waxy wheat, a new kind of genetically back‐crossed wheat, was applied to make whole bread in this study. Dough properties and bread quality of the whole waxy wheat flour, which was milled from 100% whole grains containing bran and germ, were determined. RESULTS: Whole waxy wheat had lower protein and lipid contents but higher dietary fiber content than whole regular wheat flour. Pasting temperature and viscosity of the whole waxy wheat flour were significantly lower than those of the whole regular wheat. However, the white wheat flour milled from wheat grains with 48% recovery had significantly higher peak viscosity than the whole waxy wheat. Bread made from the whole waxy wheat flour was significantly softer than that from the whole regular wheat flour during storage. However, bread made from whole waxy wheat had significantly lower specific volume than that from the white waxy flour because of the high amount of dietary fiber. Addition of cellulase increased paste viscosity, lowered dough mixing properties and reduced the firmness of the bread. The addition of pentosanase also increased paste viscosity, lowered dough mixing properties, improved loaf volume of bread but increased the firmness of breadcrumbs, while the addition of α‐amylase only increased final viscosity of flour and did not affect dough properties and bread qualities of whole waxy wheat flour. CONCLUSION: As a result, waxy wheat shows superior properties for making whole breads. Additional enzymes are also necessary to improve bread quality and nutritive values of whole waxy bread. Copyright © 2007 Society of Chemical Industry     

Investigation of α-glucosidase inhibitory activity of wheat bran and germ

Postprandial hyperglycaemia is a primary risk factor in the development of Type 2 diabetes. α-Glucosidase inhibitors that reduce postprandial hyperglycaemia have a key role in the treatment of Type 2 pre-diabetic states and also have the potential to reduce the progression to complications of diabetes. Epidemiological studies showed that risk for Type 2 diabetes mellitus was decreased with consumption of whole grains. The bran and germ of whole wheat are major components of whole grain consumption and are widely accepted as important ingredients in many low glycaemic index (GI) foods. In this study, the α-glucosidase inhibitory activity of wheat bran and germ was investigated. The active compounds were screened using an in vitro enzyme-inhibitory assay guided fractionation. Potent α-glucosidase inhibitory compounds from wheat germ were identified as phosphatidic acids, 1,2-dilinoleoylglycero-3-phosphate and 1-palmitoyl-2-linoleoyl-glycero-3-phosphate. The low GI property of whole grain wheat could be attributed to these α-glucosidase inhibitory phosphatidic acids, which have the potential to prevent or treat Type 2 diabetes.     

小麦胚和小麦麸皮的成分及其开发利用

小麦胚和小麦麸皮是小麦加工中的副产品,小麦胚中含有丰富的蛋白质,油脂,ＶＥ等成分,小麦麸皮中含有具生理活性的膳食纤维,低聚糖和酶。开发利用小麦胚和小麦麸皮具有较高的经济价值和社会意义。     

Microstructure and nutrient composition of hairless canary seed and its potential as a blending flour for food use

Canary seed is a true cereal with unique composition. The current study employed light and fluorescence microscopy to visualise starch, protein, phenolics and phytate in hairless canary seed (CDC Maria), a cultivar developed potentially for food use. Macronutrients, minerals and vitamins were evaluated in the developed cultivar and compared with a commercial hairy canary seed, cv. Keet. A control common wheat, cv. Katepwa, was grown adjacent to the canary seed varieties. The compositions of the two canary seed varieties were found to be similar with an average of 55.8 g/100 g of starch, 23.7% g/100 g of protein, 7.9% of crude fat, 7.3 g/100 g of total dietary fibre, 1.8 g/100 g of soluble sugar and 2.3 g/100 g of total ash in the whole grain. Regardless of the milling fraction (whole grain flour, white flour or bran), canary seed had more protein and crude fat and less starch, total dietary fibre and soluble sugar than had wheat. It also had higher concentrations of several minerals and vitamins than did wheat. The structure of the canary seed grain exhibited compound starch granules and protein bodies embedded in a protein matrix similar to that of the oat kernel. Baking tests showed that bread made with 100% hairless canary seed flour was significantly lower in loaf volume and crust and crumb colour than was wheat bread. However, bread with loaf volume, specific volume and crust colour comparable to those of the bread control was achieved by using up to 25% of hairless canary seed or 15% of roasted canary seed flour, thus demonstrating its potential for food applications.     

全麦面包的制作及其品质研究

参考美国FDA制定的全谷物食品标准,在小麦粉中添加不同数量的新鲜麦胚和麸皮制作全麦面包,通过对面包的体积、形态、口感等感官品质的评定分析,确定全谷物原料在全麦面包中的最适添加量。制作的全麦面包产品,香气和味道好于普通面包,内部结构和表面形态正常,口感稍有粗糙。     

Application of cereals and cereal components in functional foods: a review

The food industry is directing new product development towards the area of functional foods and functional food ingredients due to consumers' demand for healthier foods. In this respect, probiotic dairy foods containing human-derived Lactobacillus and Bifidobacterium species and prebiotic food formulations containing ingredients that cannot be digested by the human host in the upper gastrointestinal tract and can selectively stimulate the growth of one or a limited number of colonic bacteria have been recently introduced into the market. The aim of these products is to affect beneficially the gut microbial composition and activities. Cereals offer another alternative for the production of functional foods. The multiple beneficial effects of cereals can be exploited in different ways leading to the design of novel cereal foods or cereal ingredients that can target specific populations. Cereals can be used as fermentable substrates for the growth of probiotic microorganisms. The main parameters that have to be considered are the composition and processing of the cereal grains, the substrate formulation, the growth capability and productivity of the starter culture, the stability of the probiotic strain during storage, the organoleptic properties and the nutritional value of the final product. Additionally, cereals can be used as sources of nondigestible carbohydrates that besides promoting several beneficial physiological effects can also selectively stimulate the growth of lactobacilli and bifidobacteria present in the colon and act as prebiotics. Cereals contain water-soluble fibre, such as beta-glucan and arabinoxylan, oilgosaccharides, such as galacto- and fructo-oligosaccharides and resistant starch, which have been suggested to fulfil the prebiotic concept. Separation of specific fractions of fibre from different cereal varieties or cereal by-products, according to the knowledge of fibre distribution in cereal grains, could be achieved through processing technologies, such as milling, sieving, and debranning or pearling. Finally, cereal constituents, such as starch, can be used as encapsulation materials for probiotics in order to improve their stability during storage and enhance their viability during their passage through the adverse conditions of the gastrointestinal tract. It could be concluded that functional foods based on cereals is a challenging perspective, however, the development of new technologies of cereal processing that enhance their health potential and the acceptability of the food product are of primary importance.     

Stability of the mycotoxin deoxynivalenol (DON) during the production of flour-based foods and wheat flake cereal

Deoxynivalenol (DON) is a mycotoxin found in cereal grains and cereal-based foods. DON concentrations in finished products are reduced under some processing conditions, but not others. DON concentrations in flour, wheat and selected foods made from them under commercially relevant conditions were compared by GC with electron capture detection. Average concentrations (n = 9/item) in cookies, crackers and pretzels ranged from 61% (cookies) to 111% (pretzels) compared with flour (100% = 0.46 μg g?1). Lesser amounts were found in donuts and bread: their respective DON concentrations were 44% and 30% that of flour. Mass balance estimates for DON (μg g?1 flour equivalents) ranged from 50% (bread = 0.23 μg g?1 flour equivalents) to 120% (donuts), indicating that dilution by recipe ingredients contributed to DON reductions in bread and accounted for all of the apparent reduction in donuts. Mass balance estimates averaged 76% (crackers) to 107% (pretzels) for the other flour products. DON concentrations were higher in cereal flakes (0.55 μg g?1 in the finished product and 0.58 μmg g?1 on a mass balance basis) than in wheat (0.40 μg g?1), suggesting that DON concentrations might increase during processing of wheat cereals under some conditions. In summary, DON concentrations of finished food products were reduced ≥ 50% only in bread and donuts. Reduction in bread resulted from a combination of DON ‘loss’ and dilution by recipe ingredients whereas the reduction in donuts was due entirely to dilution. These results are further evidence of DON stability during the preparation of popular flour or wheat-based products.     

Improving storage property of wheat bran by steam explosion

Steam explosion (SE) was exploited for stabilizing wheat bran (WB), and its effects on nutrients retention of WB were investigated. Result showed that SE could effectively inactivate lipase and peroxidase of WB at 0.8 MPa (170 °C) for 5 min while lipid and protein were not loss. Total flavonoids, phenolics contents, soluble dietary fibre content and DPPH radical scavenging activity in WB after SE increased by 198%, 83%, 27% and 21% respectively compared with those after conventional thermal sterilization (0.1 MPa (121 °C) for 20 min), while fatty acid value and peroxide value and insoluble dietary fibre content deceased by 21%, 75% and 24%, respectively. SE inhibited hydrolysis rancidity of wheat bran and reconstituted whole wheat flour (wholemeal) in the accelerated storage test. Therefore, SE may be a new efficient technology that could stabilize cereal bran and further promote its products development.     

Changes in Particle Size Distribution of Bran and Flour Obtained from Vacuum Impregnated and Infra-red Heated Wheat Grain

This study aims to provide comprehensive information on the process of vacuum impregnation of wheat grains. Vacuum impregnation, saturating materials with additional liquid components, is a well-known process originally developed to ensure leak tightness or reduce the porosity of various materials. We describe its potential uses in the food processing industry relating to the impregnation of grains and leguminous plant seeds. The objective of the study was to determine the influence of impregnation and infrared heating of wheat grains on flour efficiency, moisture content and particle size distribution in the resulting flour and bran. The experimental material comprised three varieties of wheat. The results showed that the method of preparing the wheat grains for milling combined with impregnation had a significant impact on the particle size distribution of bran but not on the particle size distribution of flour. A more complete view of the process characteristics requires further investigation of factors related to the structural and textural properties of the impregnated material, factors which are highly varied in the case of food materials and food products.