Nutritional Components of Wheat Based Food: Composition, Properties, and Uses.

Wheats (bread and durum wheats) and their main end-use products (particularly bread and pasta) have an important role in the Mediterranean diet as they substantially contribute to nutrient intake [...].

Antioxidants and Phenolic Acid Composition of Wholemeal and Refined-Flour, and Related Biscuits in Old and Modern Cultivars Belonging to Three Cereal Species.

Cereals are a good source of phenolics and carotenoids with beneficial effects on human health. In this study, a 2-year evaluation was undertaken on grain, wholemeal and refined-flour of two cultivars, one old and one modern, belonging to three cereal species. Wholemeal of selected cultivars for each species was used for biscuit making. In the grain, some yield-related traits and proteins (PC) were evaluated. In the flours and biscuits, total polyphenols (TPC), flavonoids (TFC), proanthocyanidins (TPAC), carotenoids (TYPC) and antioxidant activities (DPPH and TEAC) were spectrophotometrically determined, whereas HPLC was used for the composition of soluble free and conjugated, and insoluble bound phenolic acids. Species (S), genotype (G) and 'SxG' were highly significant for yield-related and all antioxidant traits, whereas cropping year (Y) significantly affected yield-related traits, PC, TPC, TPAC, TEAC and 'SxGxY' interaction was significant for yield-related traits, TPAC, TYPC, TEAC, DPPH and all phenolic acid fractions. Apart from the TYPC that prevailed in durum wheat together with yield-related traits, barley was found to have significantly higher values for all the other parameters. Generally, the modern cultivars are richest in antioxidant compounds. The free and conjugated fractions were more representative in emmer, while the bound fraction was prevalent in barley and durum wheat. Insoluble bound phenolic acids represented 86.0% of the total, and ferulic acid was the most abundant in all species. A consistent loss of antioxidants was observed in all refined flours. The experimental biscuits were highest in phytochemicals than commercial control. Although barley biscuits were nutritionally superior, their lower consumer acceptance could limit their diffusion. New insights are required to find optimal formulations for better nutritional, sensorial and health biscuits.

Comparative Analysis of Qualitative and Bioactive Compounds of Whole and Refined Flours in Durum Wheat Grains with Different Year of Release and Yield Potential.

Durum wheat varieties are important sources of nutrients and provide remarkable amounts of phytochemicals. Especially, phenolics, which are mostly located in external layers of grains, have recently gained increased interest due to their high antioxidant power. This study aimed to evaluate the differences in the quality traits and phenolic compounds' concentration (e.g., phenolic acids) of different durum wheat genotypes, namely four Italian durum wheat cultivars and a USA elite variety, in relation to their yield potential and year of release. Phenolic acids were extracted both from wholemeal flour and semolina and analysed through HPLC-DAD analysis. Ferulic acid was the most represented phenolic acid, both in the wholemeal flour (438.3 µg g-1 dry matter) and in semolina (57.6 µg g-1 dry matter) across all cultivars, followed by p-coumaric acid, sinapic acid, vanillin, vanillic acid, syringic acid, and p-hydroxybenzoic acid. Among the cultivars, Cappelli showed the highest phenolic acid content, whilst Kronos had the lowest one. Negative correlations occurred between some phenolic acids and morphological and yield-related traits, especially for Nadif and Sfinge varieties. On the contrary, durum wheat genotypes with low yield potential such as Cappelli accumulated higher concentrations of phenolic acids under the same growing conditions, thereby significantly contributing to the health-promoting purposes.

Durum Wheat Bread with a Potentially High Health Value through the Addition of Durum Wheat Thin Bran or Barley Flour.

The enrichment of semolina bread with prebiotic ingredients such as ß-glucans may exert health-promoting effects. This work presents the results of a general recipe development aimed at improving the nutritional value of bakery products. In this study, increasing amounts (0%, 2%, 5%, 7%, and 10%) of thin bran or barley flour were added into re-milled durum wheat semolina to prepare breads. The technological quality of doughs and breads was investigated. In general, the Farinograph water absorption of flour and dough stability increased with increasing inclusion levels of barley flour or thin bran (up to 73.23% and 18.75 min, respectively), contrarily to the increase of dough development time only in barley inclusion (4.55 min). At the same time, the softening index decreased for almost all of these, except for 2% of thin bran or barley flour inclusion. At Mixograph, mixing time increased (up to 5.13 min) whilst the peak height decreased. The specific volume and hardness of loaf differently decreased for almost all thesis (ranges 12.6-24.0% and 39.4-45.5%, respectively). The other quality parameters remained unchanged compared with semolina bread. After baking, ß-glucan levels increased differently at all the inclusion levels (2.35-fold, on average). The breadcrumb color was deep brown, while the crust became lighter in color. The breads contain ß-glucans even at low percentages of barley/bran inclusions while maintaining their technological performance. In conclusion, the results show an interesting potential of barley flour or thin bran as ingredients in breadmaking to increase the ß-glucans daily intake, but further investigations are needed to achieve improved quality features.

Unlocking the molecular basis of wheat straw composition and morphological traits through multi-locus GWAS.

BACKGROUND: Rapid reductions in emissions from fossil fuel burning are needed to curb global climate change. Biofuel production from crop residues can contribute to reducing the energy crisis and environmental deterioration. Wheat is a renewable source for biofuels owing to the low cost and high availability of its residues. Thus, identifying candidate genes controlling these traits is pivotal for efficient biofuel production. Here, six multi-locus genome-wide association (ML-GWAS) models were applied using 185 tetraploid wheat accessions to detect quantitative trait nucleotides (QTNs) for fifteen traits associated with biomass composition. RESULTS: Among the 470 QTNs, only 72 identified by at least two models were considered as reliable. Among these latter, 16 also showed a significant effect on the corresponding trait (p.value < 0.05). Candidate genes survey carried out within 4 Mb flanking the QTNs, revealed putative biological functions associated with lipid transfer and metabolism, cell wall modifications, cell cycle, and photosynthesis. Four genes encoded as Cellulose Synthase (CeSa), Anaphase promoting complex (APC/C), Glucoronoxylan 4-O Methyltransferase (GXM) and HYPONASTIC LEAVES1 (HYL1) might be responsible for an increase in cellulose, and natural and acid detergent fiber (NDF and ADF) content in tetraploid wheat. In addition, the SNP marker RFL_Contig3228_2154 associated with the variation in stem solidness (Q.Scsb-3B) was validated through two molecular methods (High resolution melting; HRM and RNase H2-dependent PCR; rhAMP). CONCLUSIONS: The study provides new insights into the genetic basis of biomass composition traits on tetraploid wheat. The application of six ML-GWAS models on a panel of diverse wheat genotypes represents an efficient approach to dissect complex traits with low heritability such as wheat straw composition. The discovery of genes/genomic regions associated with biomass production and straw quality parameters is expected to accelerate the development of high-yielding wheat varieties useful for biofuel production.

Specialized metabolites: Physiological and biochemical role in stress resistance, strategies to improve their accumulation, and new applications in crop breeding and management.

Specialized plant metabolites (SPMs), traditionally referred to as 'secondary metabolites', are chemical compounds involved in a broad range of biological functions, including plant responses to abiotic and biotic stresses. Moreover, some of them have a role in end-product quality with potential health benefits in humans. For this reason, they became an important target of studies focusing on their mechanisms of action and use in crop breeding and management. In this review we summarize the specific role of SPMs in physiological processes and in plant resistance to abiotic and biotic stresses, and the different strategies to enhance their production/accumulation in plant tissues under stress, including genetic approaches (marker-assisted selection and biotechnological tools) and agronomic management (fertilizer applications, cultivation method and beneficial microorganisms). New crop management strategies based on the direct application of the most promising compounds in form of plant residuals or liquid formulations are also described.

Comparison of gluten peptides and potential prebiotic carbohydrates in old and modern Triticum turgidum ssp. genotypes.

Old wheat genotypes are perceived by consumers as healthier than modern ones. The release of gluten peptides with in vitro digestion and the content of potentially prebiotic carbohydrates (i.e. resistant fraction of starch and cell-wall associated dietary fiber) were evaluated in tetraploid wheats, namely 9 old and 3 modern Triticum turgidum ssp. genotypes. Simulated digestion of wholemeal flours yielded 152 major peptides, 59 of which were attributed a sequence. Principal component analysis revealed that peptide profiles were variable in old genotypes, unlike in modern ones. Digestion of old genotypes generally yielded peptides in greater concentration. In particular, 5 peptides of γ-gliadin, known to trigger the adaptive immune reaction, and two peptides of α-gliadin, known to be toxic to celiac patients, were particularly abundant in some old varieties. Resistant starch (RS) was negligible in modern genotypes (<0.6%), but it was remarkably abundant in some old varieties, reaching the highest value in Dauno III (8.5%, P < 0.05). Dauno III also presented the highest amount of soluble fiber (4.2%, P < 0.05). Pasta was made with an old and a modern genotype (Dauno III and PR22D89, respectively) with opposite RS content. Pasta making and cooking affected starch digestibility, overtaking differences between genotypes and yielding the same amount of RS for both the varieties (approx. 1.7%). The data herein presented suggest that the wholemeal flours of old tetraploid wheat genotypes could not boast particular claims associated to a lower exposure to gluten peptides and, if cooked, to a prebiotic potential.

Durum wheat breads 'high in fibre' and with reduced in vitro glycaemic response obtained by partial semolina replacement with minor cereals and pulses.

The aim of this study was to develop fortified breads of durum wheat semolina (DW) partially substituted at 10%, 15%, 20% and 30% with white sorghum or yellow pea wholemeal flours (WS, YP, respectively) or using wholemeal flour from a natural mixture of rye and durum wheat (RDW). The physico-chemical composition of the raw materials, rheological properties of dough, the bread quality characteristics, glycaemic index and sensory quality of bread were examined. Compared to 100% DW, 100% YP had twice the protein levels, RDW had almost three times the dietary fibre, while the colorimetric indices for WS and YP flour addition showed increased redness (for RDW) and similar yellowness (for YP). With respect to the control dough (100% DW), RDW and addition of WS or YP produced showed negative impact on water absorption (RDW, WS), stability (RDW, YP), dough strength (RDW, WS, YP), tenacity and extensibility ratio (RDW, YP), loaf volume (RDW, WS, YP), yellowness (RDW, WS) and sensory acceptance of bread (RDW, WS). However, these changes were counterbalanced by higher dietary fibre and lower glycaemic index of the breads, especially for RDW and at high additions of WS and YP (20-30%). Moreover, breads fortified with YP were better in terms of colour and overall acceptability scores.

Milling overrides cultivar, leavening agent and baking mode on chemical and rheological traits and sensory perception of durum wheat breads.

Smell and aroma are important determinants of consumer acceptance, so gaining deeper insight into bread smell and aroma perception is a research goal. Sixteen combinations of four variables were investigated, to evaluate the contributions of bread chemical and rheological properties and volatile organic compounds (VOCs) towards sensory acceptability of breads: genotypes (landrace vs. modern); types of flour (wholemeal vs. semolina); leavening agents (brewing yeast vs. sourdough starter); and baking modes (gas-fired vs. wood-fired). Milling had the greatest impact over the other treatments for the rheological and chemical properties, including for VOCs, with great impact on the sensory traits of the flours and breads. The processing phases had great impact on smell and aroma, as defined through formation of alcohols, aldehydes, terpenes, and other compounds (e.g., ethylbenzene, 2-pentylfuran, methoxyphenyl oxime). Leavening agent had great impact on sensory perception, although breads from the sourdough starter were perceived as with lower taste and colour than the brewing yeast. Baking mode had no relevant role on sensory perception. These data strongly undermine the belief of a 'better product' that is frequently attributed to old genotypes versus modern cultivars, and indicate that the milling and the bread-making processes determine the quality of the end product.

Selenium-enriched durum wheat improves the nutritional profile of pasta without altering its organoleptic properties.

Two field experiments were conducted over three growing seasons (2006-07, 2008-09 and 2009-10) to evaluate Se-enriched pasta through foliar fertilization at various rates and timing of application on 4 durum wheat varieties. Our findings confirm the effectiveness of foliar Se fertilization to increase Se concentrations in durum wheat grain, even at high Se rates (120gSeha(-1)). Se fortification was significant across different genotypes, with greater Se accumulation in landraces ('Timilia') and obsolete varieties ('Cappelli'), with respect to modern varieties. The Se content in the grain was increased by up to 35-fold that of the untreated control. The Se concentration decreased during milling (11%), while processing and cooking of pasta did not show significant decreases. This biofortification stategy had no effects on grain quality parameters, except for reduced gluten index in the high-gluten variety PR22D89, as well as for the sensorial properties of the spaghetti.

Optimization of durum wheat bread from a selenium-rich cultivar fortified with bran.

In this work the effect of bran addition (5 %, 10 %, 15 %, 20 %, 25 %, 30 %) on sensory, nutritional and mechanical properties of bread made from a durum wheat semolina enriched with selenium (cultivar PR22D89) was addressed; traditional and whole-meal bread from the same cultivar PR22D89, without any further bran addition, were also investigated for comparative purpose. In order to improve the durum wheat functional bread, different structuring agents (agar agar, gellan gum, guar seed flour, hydroxy-propyl-cellulose, modified food starch-CAPSUL® and tapioca starch) were firstly screened and then optimized. Sensory, textural and nutritional properties of bread were studied in each step. Results showed that bread from PR22D89 cultivar with addition of bran up to 30 % was completely accepted from the textural, nutritional and sensory points of view with proper utilization of guar seed flour or modified food-starch (2 %).

Use of purple durum wheat to produce naturally functional fresh and dry pasta.

In this study, the effects of different milling procedures (roller-milling vs. stone-milling) and pasta processing (fresh vs. dried spaghetti), and cooking on the antioxidant components and sensory properties of purple durum wheat were investigated. Milling and pasta processing were performed using one purple and one conventional non-pigmented durum wheat genotypes, and the end-products were compared with commercial pasta. The results show that the stone milling process preserved more compounds with high health value (total fibre and carotenoids, and in the purple genotype, also anthocyanins) compared to roller-milling. The drying process significantly (p<0.05) reduced the content of anthocyanins (21.42 µg/g vs. 46.32 µg/g) and carotenoids (3.77 µg/g vs. 4.04 µg/g) with respect to the pasteurisation process involved in fresh pasta production. The sensory properties of pasta from the purple genotype did not significantly differ from commercial wholemeal pasta, and its in vitro glycemic index was even lower. Thus, it is possible to consider this genetic material as a good ingredient for the production of functional foods from cereals naturally rich in bioactive compounds.

Effects of Heat Stress on Metabolite Accumulation and Composition, and Nutritional Properties of Durum Wheat Grain.

Durum wheat (Triticum turgidum (L.) subsp. turgidum (L.) convar. durum (Desf.)) is momentous for human nutrition, and environmental stresses can strongly limit the expression of yield potential and affect the qualitative characteristics of the grain. The aim of this study was to determine how heat stress (five days at 37 °C) applied five days after flowering affects the nutritional composition, antioxidant capacity and metabolic profile of the grain of two durum wheat genotypes: "Primadur", an elite cultivar with high yellow index, and "T1303", an anthocyanin-rich purple cultivar. Qualitative traits and metabolite evaluation (by gas chromatography linked to mass spectrometry) were carried out on immature (14 days after flowering) and mature seeds. The effects of heat stress were genotype-dependent. Although some metabolites (e.g., sucrose, glycerol) increased in response to heat stress in both genotypes, clear differences were observed. Following the heat stress, there was a general increase in most of the analyzed metabolites in "Primadur", with a general decrease in "T1303". Heat shock applied early during seed development produced changes that were observed in immature seeds and also long-term effects that changed the qualitative and quantitative parameters of the mature grain. Therefore, short heat-stress treatments can affect the nutritional value of grain of different genotypes of durum wheat in different ways.

Impact of domestication on the phenotypic architecture of durum wheat under contrasting nitrogen fertilization.

The process of domestication has led to dramatic morphological and physiological changes in crop species due to adaptation to cultivation and to the needs of farmers. To investigate the phenotypic architecture of shoot- and root-related traits and quantify the impact of primary and secondary domestication, we examined a collection of 36 wheat genotypes under optimal and nitrogen-starvation conditions. These represented three taxa that correspond to key steps in the recent evolution of tetraploid wheat (i.e. wild emmer, emmer, and durum wheat). Overall, nitrogen starvation reduced the shoot growth of all genotypes, while it induced the opposite effect on root traits, quantified using the automated phenotyping platform GROWSCREEN-Rhizo. We observed an overall increase in all of the shoot and root growth traits from wild emmer to durum wheat, while emmer was generally very similar to wild emmer but intermediate between these two subspecies. While the differences in phenotypic diversity due to the effects of primary domestication were not significant, the secondary domestication transition from emmer to durum wheat was marked by a large and significant decrease in the coefficient of additive genetic variation. In particular, this reduction was very strong under the optimal condition and less intense under nitrogen starvation. Moreover, although under the optimal condition both root and shoot traits showed significantly reduced diversity due to secondary domestication, under nitrogen starvation the reduced diversity was significant only for shoot traits. Overall, a considerable amount of phenotypic variation was observed in wild emmer and emmer, which could be exploited for the development of pre-breeding strategies.