Effect of baking on free and bound phenolic acids in wholegrain bakery products

Phenolic compounds, particularly ferulic acid the most abundant phenolic in wheat, are the major contributors to the in vitro antioxidant capacity. They are present in wheat in free and bound forms which affect their bioavailability. Thus the current study aims to investigate changes in free and bound phenolic acids occurred during baking in wholegrain bread, cookie and muffin. The products were also fortified with lutein due to its proved health benefits, and were previously evaluated with regard to lutein stability and bioavailability and antioxidant properties. The control and fortified wholegrain bakery products contained reasonable amounts of free and bound phenolic acids with bread products exhibiting the highest level per serving (0.6 and 11.7 mg, respectively). Ferulic acid was the principal phenolic both in the free or bound extracts of the three products followed by p-coumaric acid in the bound extracts. Baking resulted in an increase in free phenolic acids in the three products, while bound phenolic acids decreased in bread and slightly changed in cookie and muffin products. Though the effect of baking appeared to be dependent on type of baked product, type of phenolic, recipe and baking conditions, the wholegrain products should be considered good sources of phenolic antioxidants.     

Comparative analysis of dough rheology and quality of bread baked from fortified and high-in-fiber flours

The research, evaluated the rheological properties of dough and final bread quality production, in function of time, made from wheat refined flour that was enriched with an oat dietary fiber in two dosages (WOF 6% and WOF 12%), spelt flour and two types of wholegrain flour: wholegrain (full milling) and wholemeal (one-step milling). The rheological measurements revealed that the highest instantaneous compliance (J₀) was observed in the wholemeal sample and the lowest was in the WOF 6%. The lowest specific volume was observed in the wholegrain bread (0.82 cm³/g), while the highest was observed in the control white bread sample (1.60 cm³/g). The most rapid loss of moisture appeared in white bread. The moisture content was significantly influenced by the type of flour, day of storage and the interaction of these two variables (p ≤ 0.01). The hardest was the sample of wholegrain bread on the first and third day. The smallest pores were noticed in WOF 12% sample. In water extraction, white bread and WOF 12% were comparable and there were no significant differences between spelt bread and wholegrain bread. THE WOF 12% sample had the optimal ratio of health benefits and technological properties.     

HealthBread: Wholegrain and high fibre breads with optimised textural quality

The aim of this study was to develop healthy wholegrain and high fibre bread products with sensory attributes similar to white bread by applying a combination of technological steps: the use in addition to flour of a specific wheat fraction with high levels of fibre and micronutrients, bioprocessing of this fraction with enzymes and yeast (pre-fermentation) and by the optimisation of dough formulation. The pre-fermentation can be modelled and optimised to improve the bioavailability of nutrients without major fibre degradation, including a +200% increased soluble free ferulic acid level, and to improve its technical functionality in the dough mixing process. It also had a positive effect on the textural quality of bread.An experimental design approach was used to achieve optimal dough formulation based on the use of pre-fermentation, vital gluten and enzymes in the dough.Commercial bread products with optimised sensory product quality were developed with high nutritional quality - being high in fibre, and a source of important micronutrients such as iron, magnesium, zinc and folate. The study shows that it is possible to develop nutritionally improved bread products with textural quality similar to white bread.     

Low moisture milling of wheat for quality testing of wholegrain flour

The objective of this study was to produce wholegrain wheat flour on a laboratory-scale with particle size distributions similar to commercially-milled samples without re-milling the bran. The moisture contents of four hard winter wheat cultivars were adjusted to 7.29–7.98% (by drying), 9.00–10.6% (“as is”), and 15.6% (by tempering) prior to milling into wholegrain flour. The moisture treatments appeared to affect the partitioning of wholegrain flour particles into each of three categories: fine (<600 μm), medium (600–849 μm) and coarse (≥850 μm). When the distributions of particles were grouped into these categories, wholegrain flours made from dried and “as is” wheat fell within the values for commercial wholegrain flours, while that from tempered wheat contained more coarse particles than even the coarsest commercial wholegrain flour. Loaf volumes and crumb firmness were not significantly different between bread made from wholegrain flour that had been produced from dried or “as is” wheat, but loaf volume was significantly lower and bread crumb firmness was significantly higher when wholegrain flour from tempered wheat was used. These results show that wheat may be milled without tempering to produce wholegrain flour with particle size similar to some commercially-milled flours without needing to re-grind the bran.     

Low moisture milling of wheat for quality testing of wholegrain flour

The objective of this study was to produce wholegrain wheat flour on a laboratory-scale with particle size distributions similar to commercially-milled samples without re-milling the bran. The moisture contents of four hard winter wheat cultivars were adjusted to 7.29–7.98% (by drying), 9.00–10.6% (“as is”), and 15.6% (by tempering) prior to milling into wholegrain flour. The moisture treatments appeared to affect the partitioning of wholegrain flour particles into each of three categories: fine (<600 μm), medium (600–849 μm) and coarse (≥850 μm). When the distributions of particles were grouped into these categories, wholegrain flours made from dried and “as is” wheat fell within the values for commercial wholegrain flours, while that from tempered wheat contained more coarse particles than even the coarsest commercial wholegrain flour. Loaf volumes and crumb firmness were not significantly different between bread made from wholegrain flour that had been produced from dried or “as is” wheat, but loaf volume was significantly lower and bread crumb firmness was significantly higher when wholegrain flour from tempered wheat was used. These results show that wheat may be milled without tempering to produce wholegrain flour with particle size similar to some commercially-milled flours without needing to re-grind the bran.     

The influence of fermentation processes and cereal grains in wholegrain bread on reducing phytate content

Wholegrain bread is generally thought of as being more healthy than white bread due to it having a higher content of dietary fibre, vitamins (especially vitamin B and E) and many important minerals. However, wholegrain bread also contains high levels of phytate (myo-inositolhexakisphosphate, InsP-6) which may bind desirable nutrients, preventing their absorption in the gut and thereby reducing the nutritional value of the end product. In order to evaluate factors influencing phytate levels, the effects of fermentation and selected wholemeal flours from rye, oats and wheat were investigated. Phytate levels were assessed using a spectrophotometric assay based on the measurement of iron with 2,2′-bipyridine. Phytate decreased in freshly ground wholegrain flour dough during the fermentation process with time of fermentation being the most important factor. Fermentation temperature was found to make only a small difference to the process of phytate reduction. Since the potential benefits of wholemeal breads incorporating various grains (e.g. oats and rye) are increasingly evident, this research has important implications for human health.     

Effect of genetic variation on phenolic acid and policosanol contents of Pegaso wheat lines

Total phenolic acid and policosanol contents and compositions of bran from an Italian bread wheat variety Pegaso and its 11 near-isogenic lines were measured. The near-isogenic wheat lines differed at one or more loci coding for storage proteins. The genetic variation included deletions, additions and/or combinations of variations. Almost 95% or more of phenolic acids were in the bound form. Ferulic acid was the predominant bound phenolic acid present in wheat bran samples. Other phenolic acids were p-coumaric, vanillic and syringic acids. Tetracosanol, docosanol, hexacosanol, octacosanol, tricosanol and heneicosanol were found as major policosanol compounds in their decreasing order. Highly significant genotypic differences were observed in total phenolic acid and policosanol concentrations. None of the genetic lines had higher phenolic acid contents than the parent line Pegaso, whereas some of the lines had more policosanol levels. In general, both total phenolic acid composition and contents were higher with genetic lines that varied at Glu-1 loci with 2+Dy high molecular weight glutenin subunit (HMW-GS) (Pegaso 184), variation at Gli-D2 loci (Pegaso 219) and single null A1 (variation at Gli-1/Glu-3 loci; Pegaso 30). Highest total policosanol content was observed with the double null at Glu-A1/Glu-D1 loci (Pegaso 236). These findings may lead to new opportunities for wheat breeders and eventually commercial wheat growers to promote the production of wheat with enhanced levels of health beneficial compounds.     

Determination of phenolic acid concentrations in wheat flours produced at different extraction rates

High-performance liquid chromatography (HPLC) was used to determine the distribution of phenolic acids in wheat flours produced from five milling extraction rates ranging from 60% to 100% in four cultivars sown in two locations in the 2008–2009 season. Considerable variation was observed in free and bound phenolic acids, and their components in flours with different extraction rates. Most phenolic acids, including the component ferulic, were present in the bound form (94.0%). Ferulic (51.0%) was the predominant phenolic acid in wheat grain, and caffeic (22.8%) and p-coumaric (17.6%) acids were abundant. The phenolic acids and their components were all significantly influenced by effects of cultivar, milling, location, and cultivar × milling interaction, with milling effect being the predominant. The proportions of phenolic compounds varied considerably among milling extractions and cultivars, and their levels depended on both initial grain concentrations and on selection of milling extraction that was incorporated into the final product. The grain phenolic acid concentrations determined ranged from 54 μg g⁻¹ in flour produced at 60% extraction rate to 695 μg g⁻¹ in flour produced at 100% extraction rate, indicating their higher concentrations in bran associated with cell wall materials. Therefore, wholemeal wheat products maximize health benefits and are strongly recommended for use in food processing.     

Phenolic acids composition,total polyphenols content and antioxidant activity of Triticum monococcum, Triticum turgidum and Triticum aestivum: A two-years evaluation

Wheat is a good source of polyphenols, plant metabolytes with beneficial effects on human health. However, little information is available on phenolic acid composition and concentration in different Triticum species, as well as on possible environmental effects. To shed some light on this issue, thirty-nine wheat accessions cropped for two years and belonging to different Triticum species (Triticum monococcum, Triticum turgidum ssp. dicoccum, turanicum and durum, Triticum aestivum ssp. spelta and aestivum) were assessed for phenolic acids (ferulic, p-coumaric, vanillic, syringic, p-hydroxybenzoic, caffeic acids and syringaldehyde), total polyphenols and antioxidant activity in soluble conjugated and insoluble bound extracts. Ferulic acid was the most abundant compound in both extracts. Insoluble bound phenolic acids represented >90% of total phenolic acids. Einkorn showed the maximum concentration of conjugated phenolic acids (50.5 mg/kg DM), while durum and bread wheats presented the highest content of bound phenolic acids (651.8 and 629.2 mg/kg DM, respectively). Cropping year influenced the concentration of conjugated but not of bound phenolic acids. A survey of phenolic acid distribution in the kernel showed that they are rare in endosperm, but abundant in germ and bran. Total polyphenols and antioxidant activity were highly correlated to phenolic acid content.     

Antioxidant activity of small grain cereals caused by phenolics and lipid soluble antioxidants

In this study, the content of soluble, free forms of phenolic compounds (total phenolics, flavonoids, PVPP (polyvinylpolypyrrolidone) bound phenolics, proanthocyanidins and phenolic acids), as well as the content of carotenoids and tocopherols, were determined in whole grains of bread and durum wheat, rye, hull-less barley and hull-less oat, each represented with four genotypes. Antioxidant activity was evaluated as radical scavenging activity with DPPH (2,2-diphenyl-1-picrylhydrazyl) reagent, as well as by hydrogen transfer reaction (reduction power) based on the reduction of Fe³⁺. Generally, a considerable variation in antioxidant activities and phytochemical contents was observed between the cereals. Remarkably higher DPPH radical scavenging ability and reducing power were detected in hull-less barley, followed by rye and hull-less oat and durum and bread wheat, indicating that small grain species have different major antioxidants with different properties. Hull-less barley had the highest content of total free phenols, flavonoids, PVPP bound phenolics and contained flavan-3-ols, not found in other species. Hull-less oat had the highest content of tocopherols, very high content of yellow pigments and PVPP bound phenolics. Ferulic acid was the major free phenolic acid in small grain cereals tested. The relationship between the content of soluble phenols, as well as reducing power and DPPH^• scavenging activity are also considered.     

Improving the quality of nutrient-rich Teff (Eragrostis tef) breads by combination of enzymes in straight dough and sourdough breadmaking

The growing interest in the benefits of wholegrain products has resulted in the development of baked products incorporating less utilised and ancient grains such as, millet, quinoa, sorghum and teff. However, addition of wholegrains can have detrimental effects on textural and sensory bread product qualities.Enzymes can be utilised to improve breadmaking performance of wholegrain flours, which do not possess the same visco-elastic properties as refined wheat flour, in order to produce a healthy and consumer acceptable cereal product.The effects of Teff grain on dough and bread quality, selected nutritional properties and the impact of enzymes on physical, textural and sensory properties of straight dough and sourdough Teff breads were investigated.Teff breads were prepared with the replacement of white wheat flour with Teff flour at various levels (0%, 10%, 20%, and 30%) using straight dough and sourdough breadmaking. Different combinations of enzymes, including xylanase and amylase (X + A), amylase and glucose oxidase (A + GO), glucose oxidase and xylanase (GO + X), lipase and amylase (L + A) were used to improve the quality of the highest level Teff breads. A number of physical, textural and sensory properties of the finished products were studied. The nutritional value of breads was determined by measuring chemical composition for iron, total antioxidant capacity, protein, fibre and fat. The obtained results were used to estimates intakes of nutrients and to compare them with DRIs.The incorporation of Teff significantly (P < 0.05) improved dietary iron levels as 30% Teff breads contained more than double the amount of iron when compared to corresponding wheat bread (6 mg/100 g v 2 mg/100 g). Addition of Teff also significantly (P < 0.05) improved total antioxidant capacity from 1.4 mM TEAC/100 g to 2.4 mM TEAC/100 g. It was estimated that an average daily allowance of 200 g of Teff enriched bread would contribute to DRIs in the range of 42-81% for iron in females, 72-138% for iron in males; 38-39% for protein in males, 46-48% for protein in females; and 47-50% of fibre in adults.The major challenge was encountered in producing the highest level of Teff bread with good textural and sensory attributes. Increasing the level of Teff significantly (P < 0.05) increased dough development time, degree of softening, crumb firmness and bitter flavour whilst decreasing the dough stability, specific loaf volume and overall acceptability of the bread. Teff breads produced with the addition of enzyme combinations showed significant improvements (P < 0.05) in terms of loaf volume, crumb firmness, crumb structure, flavour and overall acceptability in both straight dough and sourdough breadmaking.     

Low molecular phytochemicals of Indian dwarf (Triticum sphaerococcum Percival) and Persian wheat (T. carthlicum Nevski) grain

Ancient wheat grain is considered by consumers to be more natural, pro-healthy and better tolerated, so these genotypes are being steadily reintroduced to cultivation. This study presents the content and composition of phenolic acids, alkylresorcinols, sterols, tocols and carotenoids in the grain of Indian dwarf and Persian wheats, extended by characteristics of their kernels (weight, dimensions and colour). To compare these features, four other wheat species (bread, spelt, durum and einkorn wheats) were used. It was found that the grain of Indian dwarf and Persian wheat is similar in weight and dimensions to grain of einkorn wheat, while in colour to bread wheat. Among the tested samples, grain of both new genotypes was the richest source of total low molecular phytochemicals, especially phenolic acids and alkylresorcinols, while being the weakest source of carotenoids. For these wheats, an enhanced share of ferulic acid (93–95%) was found, accompanied by higher quantitative and qualitative variability of homologues within sterols, tocols and carotenoids. In turn, the alkylresorcinol composition was related to wheat ploidy level.     

Phenolic acid profiles of Chinese wheat cultivars

Phenolic acid concentrations were determined in 37 Chinese commercial winter wheat cultivars grown at a single site over two seasons, and fractions comprising free and bound types were analyzed using HPLC with measurements of individual phenolic acids in each fraction. Most of the parameters were significantly influenced by cultivar, season, and their interaction effects, with cultivar variance being predominant. Wide ranges of concentration among the 37 cultivars were observed. The average concentration of bound type was 661 μg g⁻¹ of dm, making up 97.5% of the phenolic acid determined with ferulic accounting for 70.7% of it, while free type made up only 2.5% of the phenolic acid determined with syringic accounting for 44.7% of it. Bound type was the predominant source to the grain phenolic acid concentrations determined. There were highly significant and positive correlations between bound ferulic concentration and total bound phenolic acid concentration, and between free syringic concentration and total free phenolic acid concentration. Cultivars Liangxing 66 and Zhongmai 895 were stable in concentration of components of phenolic acids across seasons, with high values of free and bound phenolic acids indicating they could be selected as parents in wheat breeding for health beneficial phenolic acid.     

Phenolic acid profiles of Chinese wheat cultivars

Phenolic acid concentrations were determined in 37 Chinese commercial winter wheat cultivars grown at a single site over two seasons, and fractions comprising free and bound types were analyzed using HPLC with measurements of individual phenolic acids in each fraction. Most of the parameters were significantly influenced by cultivar, season, and their interaction effects, with cultivar variance being predominant. Wide ranges of concentration among the 37 cultivars were observed. The average concentration of bound type was 661 μg g⁻¹ of dm, making up 97.5% of the phenolic acid determined with ferulic accounting for 70.7% of it, while free type made up only 2.5% of the phenolic acid determined with syringic accounting for 44.7% of it. Bound type was the predominant source to the grain phenolic acid concentrations determined. There were highly significant and positive correlations between bound ferulic concentration and total bound phenolic acid concentration, and between free syringic concentration and total free phenolic acid concentration. Cultivars Liangxing 66 and Zhongmai 895 were stable in concentration of components of phenolic acids across seasons, with high values of free and bound phenolic acids indicating they could be selected as parents in wheat breeding for health beneficial phenolic acid.     

Milling efficiency of triticale grain for commercial flour production

Triticale is a high yielding cereal grain, however low milling yields have discouraged its utilisation as a wheat alternative in processed flour products. This research investigated the role of hardness, grain size and tempering moisture on milling yields in modern triticale genotypes which do not exhibit shrivelled grain morphology. Replicate samples of three triticale varieties grown in two environments with a bread wheat standard were milled at five moisture contents. Both milling yield and ash content increased with decreasing tempering moisture in all genotypes. Triticale milling yield was between 7.1% and 10.1% less than wheat when tempered between 11% and 15% moisture respectively. The very hard textured triticale exhibited extremely low milling yield, similar to durum wheat. The ratio of ash in flour compared to bran was greater in triticale and the ash content of triticale flour could not be reduced to the level of wheat by alteration of tempering moisture. Surface area of larger triticale grain may also influence ideal tempering moisture, however further investigation is required. Milling yields and flour protein content in triticale can be improved by tempering triticale to lower moisture content, provided high ash content is not considered unfavourable in the final product.     

Phenolics in the bran of waxy wheat and triticale lines

The present study was designed to determine total phenolic acid contents (TPC) and compositions of bran from newly developed near-isogenic waxy wheat and triticale translocation lines. Two waxy wheat sets, Svevo (durum) and N11 (bread wheat), consisting of partial and waxy null lines and four sets of triticales (GDS7, Trim, Rhino and Rigel) having translocations at 1A.1D and 1R.1D with high molecular weight glutenin subunits (HMW-GS) 5 + 10 and 2 + 12 were investigated. Similar to non-waxy wheat, ferulic acid was the predominant phenolic acid found in waxy wheats analyzed. Two other major phenolics include p-coumaric and vanillic acids followed by lesser quantities of syringic acid. Waxy lines had higher TPC than the parent line in the N11 set, whereas the Svevo set showed the opposite trend. TPC of waxy bread wheats were correlated with amylose fractions in which the order was complete waxy < double waxy nulls < single waxy nulls. Lines with HMW-GS 2 + 12 have lower TPC than other lines in each group of triticales, except the Trim set. TPC was negatively correlated (r = −0.41; p > 0.1) with bran yields in triticale lines studied, indicating that variation in phenolics was not only due to bran yields but also to genotypic differences.     

Effects of different milling methods on flour quality and performance in steamed breadmaking

Three types of wheat: 8901 (hard wheat), Nanyang white wheat, NYWW (medium wheat), and Australian white wheat, AWW (soft wheat) were milled after debranning by abrasion and friction, and by conventional milling. The quality of flours produced by the two procedures and their performance in steamed breadmaking were evaluated. The results showed that debranning affected both the quality of flour and the steamed bread, especially for 8901 and NYWW. Debranning lowered the gluten index, maximum resistance and starch damage; whereas, it increased pericarp content, ash content, L* value, falling number and particle size distribution. The pasting properties such as peak viscosity and final viscosity of NYWWDII and 8901DII were higher than those of NYWWCII and 8901CII. Debranning had positive effects on the quality scores, volume, volume/weight, height and structure of steamed bread from second flour, except for those from soft wheat. For the two other samples, the quality scores for steamed bread were lower than that for the conventional flour. The shape and structure of steamed bread from the top flours of AWWCII and 8901CII were better than from debranned flour. The milling methods did not affect the texture of steamed bread, except in the case of second flour of NYWW.     

Effects of fermentation and heat treatments on bound-ferulic acid content and total antioxidant capacity of bread crust-like systems made of different whole grain flours

In this study, bread crust-like systems were prepared by heating (5, 15 and 30 min at 200 °C) freeze-dried fermented doughs obtained using different cereal grains. The flours of whole wheat, refined wheat, whole einkorn, whole rye, whole oat and whole maize were used. The effects of fermentation and heating on bound ferulic acid concentration and total antioxidant capacity were determined. Besides, high molecular weight fractions, containing also melanoidins formed in bread crust-like systems during heating were analyzed for their bound ferulic acid content and total antioxidant capacity. Increasing heating time at 200 °C also increased the amounts of high molecular weight fractions in the bread crust-like systems for all cereals. The total antioxidant capacity of bread crust-like samples increased significantly with heating time (p < 0.05). However, the opposite was true for the high molecular weight fractions of bread crust-like samples. Mean bound ferulic acid concentrations of different cereal flours were found to range between 78.3 mg/kg (for refined wheat) and 667.7 mg/kg (for whole einkorn). Heating had no significant effect on bound ferulic acid contents of bread crust-like systems. For all cereals, the highest concentrations of bound ferulic acid were detected in the high molecular weight fractions of bread crust-like systems heated at 200 °C for 5 min. However, bound ferulic acid concentrations significantly decreased in high molecular weight fractions as heating time increased (p < 0.05).     

Effects of wheat tempering and stone rotational speed on particle size,dough rheology and bread characteristics for a stone-milled weak flour

The poor technological performance of weak wheat flours means that they are usually considered difficult to be transformed into satisfactory bread. During milling, there are several settings that can affect flour characteristics. In this study, we tested two operative parameters that have the potential to affect flour quality – stone rotational speed and wheat tempering. Tempering moistures were set at 11%, 13%, 15%, and 17%, while stone rotational speeds were set at 173, 260, and 346 rpm. Both factors were found to affect operative milling parameters, notably flour yield, process productivity and specific energy consumption. Grain moisture had a significant effect on both dough rheology and bread characteristics (dough stability, tenacity, and extensibility). Dough stability was maximum at 13% moisture. Dough tenacity decreased as moisture increased, while extensibility increased as moisture increased. Bread specific volume and crumb specific volume were improved at 13% and 15% moisture. In conclusion, wheat tempering can be used to improve the potential of a weak flour and bread characteristics, while stone rotational speed affects operative parameters and white flour yield.     

A comparative study of physicochemical tests for quality prediction of Argentine wheat flours used as corrector flours and for cookie production

Several physicochemical tests are employed in quality evaluation of wheat. Most of the exported Argentinean wheat flour is used as corrector flour in breadmaking. A small percentage is actually used in cookie production. No study has determined which predictive tests are most suitable for the quality prediction of bread (using flour as corrector) and cookies made from Argentinean wheat. The objectives of this study were to compare the suitability of predictive tests in the assessment of wheat flour attributes in the production of bread and cookies and to establish the relationship between the tests and flour components. Several expected associations were found between the SRC test and the composition parameters. Moreover, various flour components influencing the SDS sedimentation index (SDS-SI), the Zeleny index and the alkaline water retention capacity (AWRC) were established. The cookie factor (CF) was negatively correlated with sucrose, carbonate and water SRC and with AWRC. In addition, the bread loaf specific volume (LV) was correlated with the SDS-SI, the Zeleny index and the lactic acid SRC. In conclusion, several components of Argentine wheat affecting predictive tests were found. The SRC test allowed straight assessment of the bread and cookie quality of Argentinean wheat.