Influence of steaming treatment on chemical and technological characteristics of einkorn (Triticum monococcum L. ssp. monococcum) wholemeal flour

Einkorn (Triticum monococcum ssp. monococcum) is an underutilised wheat with high protein, lutein and tocols content, particularly suited for baby and specialty foods. To study the influence of kernel steaming treatments on chemical and technological properties, seeds of five einkorn accessions and one bread wheat control (cv. Blasco) underwent different steaming conditions, and their wholemeal flours were compared for ash, protein, lutein, tocols and α-amylase content, SDS sedimentation volume and gelatinisation parameters. Furosine, a heat damage marker, was measured as well. The treatments significantly influenced most of the parameters. In particular, lutein, tocols and α-amylase diminished after steaming; SDS sedimentation volumes and most gelatinisation parameters also decreased, whereas gelatinisation temperatures and furosine contents increased. The changes were stronger under more drastic steaming conditions, although treatment × genotype influence was sometimes detected. Steaming induced migration of lutein and tocopherols from the bran and germ fractions to the kernel endosperm.     

Tocols of selected spring wheat (Triticum aestivum L.), einkorn wheat (Triticum monococcum L.) and wild emmer (Triticum dicoccum Schuebl [Schrank]) varieties

Wheat contributes significantly worldwide to antioxidant income with beneficial healthy effects. Two varieties of einkorn wheat (Triticum monococcum L. – Escana and Schwedisches Einkorn), two varieties of wild emmer [Triticum dicoccum Schuebl (Schrank)] (Rudico and Kahler Emmer) and three varieties of spring wheat (Triticum aestivum L. – Granny, Kärtner Früher and SW Kadrilj) were evaluated for tocols – tocopherols and tocotrienols by high performance liquid chromatography – electrospray ionisation tandem mass spectrometry (HPLC–ESI/MS/MS). Investigated emmer and einkorn wheat varieties have shown minor lower total tocols content in comparison with spring varieties, however significant typical levels of tocopherols and tocotrienols were found in these groups. In einkorn wheat varieties the major abundance of total tocols is represented by tocotrienols (Schwedisches Einkorn 65.0%, Escana 54.9%), in emmer wheat varieties the abundance of tocotrienols and tocopherols were similar (Rudico 48.9% of tocotrienols, Kahler Emmer 47.6%), whereas in spring bread wheat higher tocopherols (SW Kadrilj 54.5%, Kärtner Früher 60.2%, Granny 55.0%) were recorded.     

Bread from common cereal cultivars contains an important array of neglected bioactive benzoxazinoids

Bread is consumed in large quantities all over the world, and rye bread is especially popular throughout the Nordic countries. Wholemeal bread is highly recommended as a basic ingredient in daily food, because wholemeal food products generally promote good health due to their vitamin, mineral and fibre content. The literature suggests that wholemeal products have other health-promoting effects even if the ingredients responsible have not been identified. Benzoxazinoids are a group of natural products that have not previously been reported in mature grains. Here, we report for the first time the identity and quantity of 10 compounds of the benzoxazinoid family in mature grains, hydrothermally processed grains of durum wheat (Triticum durum, cv. Kamut), a commercial variety of rye (Secale cereale cv. Picasso) and an old Nordic rye landrace (S. cereale, Svedjerug), as well as in bread baked with flour milled from those grains. Concentrations of the 10 benzoxanoids were determined using LC–MS/MS and ranged from 0 to 348 nmol g⁻¹ for conventional flour, to 772–1177 nmol g⁻¹ in bread baked with flour from hydrothermally processed grains and to 3116–5570 nmol g⁻¹ in flour from hydrothermally processed grains. Benzoxazinoids possess documented physiological effects, and research into the importance of these compounds in the daily diet is therefore needed. Ongoing studies in our lab on the uptake and transformation of benzoxazinoids in mammals will be reported in the near future.     

Protein,ash, lutein and tocols distribution in einkorn (Triticum monococcum L. subsp. monococcum) seed fractions

The distribution of protein, ash, lutein, tocopherols and tocotrienols in the germ, bran and endosperm portions was studied in seeds of two einkorn accessions and one bread wheat. The two einkorns showed a higher content of most compounds, but the distribution within the kernel was similar in both species. The germ fraction showed the highest concentration of protein, lutein, α-tocopherol, β-tocopherol and total tocols. Ash, α-tocotrienol and β-tocotrienol levels were highest in the bran fraction, although significant quantities were detected also in the germ and, for tocotrienols, in the flour.     

Lipoxygenase activity in wholemeal flours from Triticum monococcum, Triticum turgidum and Triticum aestivum

To minimise lipid oxidation and maintain high carotenoid and tocol concentrations in wheat flours and products, fifty-seven accessions, belonging to different Triticum species (Triticum monococcum, Triticum turgidum and Triticum aestivum), were assessed for lipoxygenase activity. The highest enzymatic activity was observed in T. aestivum (8.02 ± 0.492 μmol/min/g DM), followed by T. turgidum (3.48 ± 0.701) and by T. monococcum (0.45 ± 0.072). While the lipoxygenase was consistently high amongst T. aestivum and steadily low amongst T. monococcum samples, the T. turgidum accessions clustered in three different groups, with low (0.12-0.91 μmol/min/g DM), medium (3.10-4.17) and high (5.57-9.51) activity. Enzymatic activity was maximum in the pH range 5-6. LOX activity was higher in the germ (206 μmol/min/g DM), than in the bran (13.4) or in the endosperm (3.1).The results demonstrate that the selection of genotypes with low LOX, a factor limiting oxidative degradation, is feasible.     

Use of low-temperature extrusion for reducing phytohemagglutinin activity (PHA) and oligosaccharides in beans (Phaseolus vulgaris L.) cv. Navy and Pinto

Bean (Phaseolus vulgaris L.) lectins and oligosaccharides are the anti-nutrients that limit dry bean consumption. The objective of this study was to study the effects of low temperature (85 °C) extrusion and steam-cooking (82 °C) on the fate of lectin, analysed as phytohemagglutinin activity (PHA), and the oligosaccharides, raffinose and stachyose. Both extrusion processing and steam-cooking significantly (p ? 0.05) reduced the lectin in bean flour by 85–95% over raw bean flours (control). The stachyose content in extruded navy bean flours was comparable to that in raw and steam-cooked flours while extruded pinto bean flour had significantly lower stachyose content than that found in raw and steam-cooked flour. The raffinose content of both navy and pinto extruded flours, though lower than raw bean flours, was significantly higher than that in steam-cooked flours. The results of this study demonstrated that extrusion processing at relatively lower temperature can be effective in eliminating lectins and reducing oligosaccharides.     

Optimization of ingredients and baking process for improved wholemeal oat bread quality

Baking technology for tasty bread with high wholemeal oat content and good texture was developed. Bread was baked with a straight baking process using whole grain oat (51/100 g flour) and white wheat (49/100 g four). The effects of gluten and water content, dough mixing time, proofing temperature and time, and baking conditions on bread quality were investigated using response surface methodology with a central composite design. Response variables measured were specific volume, instrumental crumb hardness, and sensory texture, mouthfeel, and flavour. The concentration and molecular weight distribution of β-glucan were analysed both from the flours and the bread. Light microscopy was used to locate β-glucan in the bread. Proofing conditions, gluten, and water content had a major effect on specific volume and hardness of the oat bread. The sensory crumb properties were mainly affected by ingredients, whereas processing conditions exhibited their main effects on crust properties and richness of the crumb flavour. β-glucan content of oat bread was 1.3/100 g bread. The proportion of the highest molecular weight fraction of β-glucan was decreased as compared with the original β-glucan content of oat/wheat flour. A great part of β-glucan in bread was located in the large bran pieces.     

Utilization of germinated ancient wheat (Emmer and Einkorn) flours to improve functional and nutritional properties of bread

Germinated and untreated ancient (Einkorn and Emmer) and modern (Esperia) wheat flours (0, 5, 10, 15 and 20%) were used in bread dough to improve functional and nutritional properties of bread according to (3 × 2 × 5) x 2 factorial design. Utilization of wheat varieties in the germinated form increased the ash, total dietary fiber (TDF), total yellow pigment (TYP), total phenolic content (TPC), antioxidant activities, Ca, Fe and Mg content of bread, and also the most increments in those values (except TYP) were observed in Emmer flour usage. Germinated wheat flour decreased the mean phytic acid contents of bread samples from 313.32 mg/100 g to 291.81 mg/100 g compared to untreated wheat flour. The use of ancient wheat flour (einkorn and emmer) gave lower bread volume compared to modern bread wheat flour. The use of germinated wheat flour decreased the crust and crumb L* values of the breads but increased the a* and b* values. As a result, increasing ratios of germinated ancient wheat flour increased the functional component and nutritional value of the bread, and at the same time, its usage at low ratio contributed positively to the technological quality of the bread.     

Selenium concentration and speciation in biofortified flour and bread: Retention of selenium during grain biofortification,processing and production of Se-enriched food

The retention and speciation of selenium in flour and bread was determined following experimental applications of selenium fertilisers to a high-yielding UK wheat crop. Flour and bread were produced using standard commercial practices. Total selenium was measured using inductively coupled plasma-mass spectrometry (ICP-MS) and the profile of selenium species in the flour and bread were determined using high performance liquid chromatography (HPLC) ICP-MS. The selenium concentration of flour ranged from 30 ng/g in white flour and 35 ng/g in wholemeal flour from untreated plots up to >1800 ng/g in white and >2200 ng/g in wholemeal flour processed from grain treated with selenium (as selenate) at the highest application rate of 100 g/ha. The relationship between the amount of selenium applied to the crop and the amount of selenium in flour and bread was approximately linear, indicating minimal loss of Se during grain processing and bread production. On average, application of selenium at 10 g/ha increased total selenium in white and wholemeal bread by 155 and 185 ng/g, respectively, equivalent to 6.4 and 7.1 μg selenium per average slice of white and wholemeal bread, respectively. Selenomethionine accounted for 65–87% of total extractable selenium species in Se-enriched flour and bread; selenocysteine, Se-methylselenocysteine selenite and selenate were also detected. Controlled agronomic biofortification of wheat crops for flour and bread production could provide an appropriate strategy to increase the intake of bioavailable selenium.     

Thermal properties and resistant starch content of green banana flour (Musa cavendishii) produced at different drying conditions

The objective of this research was to verify the effect of drying conditions on thermal properties and resistant starch content of green banana flour (Musa cavendishii). The green banana flour is a complex-carbohydrates source, mainly of resistant starch, and quantifying its gelatinization is important to understand how it affects food processing and the functional properties of the flour. The green banana flour was obtained by drying unripe peeled bananas (first stage of ripening) in a dryer tunnel at 52 °C, 55 °C and 58 °C and air velocity at 0.6 m s⁻¹, 1.0 m s⁻¹ and 1.4 m s⁻¹. The results obtained from differential scanning calorimetry (DSC) curves show a single endothermic transition and a flow of maximum heating at peak temperatures from (67.95 ± 0.31) °C to (68.63 ± 0.28) °C. ANOVA shows that only drying temperature influenced significantly (P < 0.05) the gelatinization peak temperature (Tp). Gelatinization enthalpy (ΔH) varied from 9.04 J g⁻¹ to 11.63 J g⁻¹ and no significant difference was observed for either temperature or air velocity. The resistant starch content of the flour produced varied from (40.9 ± 0.4) g/100 g to (58.5 ± 5.4) g/100 g, on dry basis (d. b.), and was influenced by the combination of drying conditions: flour produced at 55 °C/1.4 m s⁻¹ and 55 °C/1.0 m s⁻¹ presented higher content of resistant starch.     

Effect of damaged starch on acrylamide formation in whole wheat flour based Indian traditional staples, chapattis and pooris

Variation in acrylamide content of two Indian traditional products, chapatti and poori was observed with respect to the damaged starch content in whole wheat flour of different wheat varieties from which these products were prepared. Wheat cultivar ‘lokwan’ was milled by altering mill aperture, feed rate and moisture content to obtain whole wheat flour with damaged starch contents ranging from 6.23% to 28.12%. Acrylamide content of the chapatti and pooris prepared from such flours ranged from 12.5 to 65.5 μg/kg in chapatti, and 25.5 to 130.5 μg/kg in pooris. Impact of several additives showed 10 μmol/g flour citric acid, and 100 μmol/g flour calcium chloride to reduce acrylamide in pooris by approximately 54% and 72%, respectively, without altering the sensory analysis of the products.     

Exploitation of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours: Chemical characterization and their use for sourdough fermentation

This study aimed at characterizing the chemical and microbiological composition of Acha (Digitaria exiliis) and Iburu (Digitaria iburua) flours and at exploiting their potential for sourdough fermentation. Both the flours had a gross composition similar to other cereals. As shown by two-dimensional electrophoresis analysis, Acha flour had a higher number of prolamins with respect to Iburu flour. The opposite was found for the number of glutelin spots. The concentration of total free amino acids of Iburu flour was higher than that of Acha flour (1348 ± 34 vs. 100 ± 20 mg/kg). Pediococcus pentosaceus was the dominant species in both the flours. Several isolates were used to ferment Acha or Iburu flours. After 8 h fermentation at 30 °C, pH ranged from 3.41 to 3.83 and from 4.20 to 4.66 for Acha and Iburu sourdoughs, respectively. The highest values of TTA and concentration of lactic acid were found in almost all Iburu sourdoughs. The synthesis of acetoin and γ-amino butyric acid (GABA) was only found in Iburu sourdoughs. Data from the kinetics of acidification, synthesis of lactic and acetic acids, acetoin, and liberation of total free amino acids were elaborated by Principal Component Analysis. Sourdoughs from Acha and Iburu flour were clearly differentiated.     

In vitro starch hydrolysis and estimated glycaemic index of bread substituted with different percentage of chempedak (Artocarpus integer) seed flour

Chempedak (Artocarpus integer) seed flour (CSF) was substituted for wheat flour at different levels (0%, 10%, 20%, 30% w/w) in bread. Assessment on the in vitro starch hydrolysis was carried out to evaluate the hydrolysis index (HI) and estimated glycaemic index (EGI) of bread substituted with different levels of CSF. Kinetics of in vitro starch hydrolysis in all bread samples (with the exception for white bread) indicated a gradual increase with respect to time intervals. Bread of 30% CSF exhibited significantly lower (p < 0.05) in vitro starch hydrolysis, as compared with the other samples. Results showed that HI value decreased significantly (p < 0.05) as the levels of CSF substitution increased. Resistant starch (RS) content in bread samples was inversely related with HI value as CSF substitution levels increased, thus lowering the EGI value.     

Biochemical characterization and process stability of polyphenoloxidase extracted from Victoria grape (Vitis vinifera ssp. Sativa)

Polyphenol oxidase (PPO) was isolated from Victoria grapes (Vitis vinifera ssp. Sativa) grown in South Africa and its biochemical characteristics were studied. Optimum pH and temperature for grape PPO activity were pH 5.0 and T = 25 °C with 10 mM catechol in McIlvaine buffer as substrate. PPO showed activity using the following substances: catechol, 4 methyl catechol, d, l-DOPA, (+) catechin and chlorogenic acid. K_m and V_max values were 52.6 ± 0.00436 mM and 653 ± 24.0 OD_400 nm/min in the case of 10 mM catechol as a substrate. Eight inhibitors were tested in this study and the most effective inhibitors were found to be ascorbic acid, l-cysteine and sodium metabisulfite. Kinetic studies showed that the thermal inactivation of Victoria grape PPO followed first-order kinetics, with an activation energy, E_a = 225 ± 13.5 of kJ/mol. Both in semipurified extract and in grape juice, PPO showed a pronounced high pressure stability.     

Evaluation of the performance of flours from cross- and self-pollinating Canadian common buckwheat (Fagopyrum esculentum Moench) cultivars in soba noodles

Two Canadian cross-pollinating common buckwheat (Fagopyrum esculentum Moench) varieties, Koban and Koto, and two self-pollinating lines, BR01 and BR06, were dehulled and roller milled on a pilot mill to produce three distinct milled products, white flour, dark flour and whole groat flour. The white flours contained mostly starch (79.2–87.2%), whereas the dark flours were rich in proteins (37.1–38.7%), dietary fibre (15.2–22.0%), ash (5.49–5.99%), and fagopyritols (1420–2220 mg/100 g). The buckwheat flours were blended with wheat flour (Canada Western Red Spring straight grade flour) at 60:40 ratios and evaluated for soba noodle properties. Significant differences in milling properties, and in raw noodle colour and texture were detected among cultivars, although the impact of flour type on noodle properties was far greater. The self-pollinating lines exhibited comparable milling and soba noodle properties to Koban. Koto exhibited slightly higher white flour yield and generally firmer noodle texture compared to the other lines. White flours produced the brightest noodles, followed by whole groat and dark flours. Dark flours yielded the thickest cooked noodles with the largest maximum cutting stress and greatest resistance to compression. Noodles prepared with white flour offered the best chewiness, springiness and recovery parameters. Soba noodles prepared with dark flours contained considerably higher amounts of minerals, proteins, dietary fibre, and fagopyritols than noodles prepared with white flour.     

Thermophysical properties of mango pulp (Mangifera indica L. cv. Tommy Atkins)

The density, heat capacity and thermal conductivity of mango pulp (Mangifera indica L. cv. Tommy Atkins) were determined at moisture contents of between 0.9 and 0.52 kg kg⁻¹ (w.b.) and temperatures of between 20 and 80 °C. The experimental data were satisfactorily fitted (explained variation values >99.1%) as functions of the moisture content and temperature by using multivariate linear models. In the range of conditions considered, the moisture content exhibits a greater influence on the studied properties than temperature.     

Production of acidic extruded rice flour and its influence on the qualities of gluten-free bread

One of the greatest technological challenges in the production of gluten-free bread (GFB) is to find a low-cost ingredient capable of retaining gas during fermentation and the baking process. The use of gelatinized starch appears to show promise for this purpose. In this study, GFB was made using raw rice flour (100 g) with the addition of 10 g acidic extruded rice flour (AERF). The AERF was produced in a single-screw extruder, varying the extrusion temperature and lactic acid concentration. Response surface methodology (RSM) and the principle components analysis (PCA) were used to analyze the results. The results of RSM showed no significant difference, but the mean volume obtained with the AERF (1.95 mL g⁻¹) was still low when compared with that of wheat bread (6 mL g⁻¹). The crust and crumb colors and the texture (hardness = 173 g; chewiness = 90.5 and fracturability = 178) presented results similar to those of wheat bread and better than other GFB found in the literature. When analyzed by PCA the AERF obtained at 150 °C-0.5 mol L⁻¹ lactic acid, showed the best results for the GFB obtained. IR spectroscopy showed that no bands were found for esters (1740 cm⁻¹) in the AERFs, which could indicate that no new bonds were formed between the rice flour and the lactic acid.     

Nutritional and quality aspects of wheat sourdough bread using L. luteus and L. angustifolius flours fermented by Pedioccocus acidilactici

Lupine has the potential to be a new domestic source of vegetable protein due to its comparable quality to the commonly used soy proteins. However, the bioprocessing that take place in the production of wheat bread with non‐conventional flours could play an important role. The wholemeal Lupinus angustifolius and Lupinus luteus flours were fermented by bacteriocin‐producing strain of Pediococcus acidilactici. The effect of lupine flour supplementation on wheat bread quality, sensory and safety criteria was studied. The lupine additives significantly decreased the quality of bread. The fermented L. luteus flour (10% of flour basis) had a slightly higher positive effect on the specific volume and crumb porosity (5.4%) and lowering of crumb hardness (9.5%) than those of L. angustifolius. In contrary, consumers rated higher for bread with L. angustifolius sourdough, which contributed to a stronger taste score. The levels of tyramine, histamine and putrescine (32.6–215.8, 20.8–96.7 and 33.7–195.2 mg kg^?1, respectively) do not present a health risk for consumers due to their relatively low levels in lupine fermented products. Bioprocessing used for wheat bread production with lupine flour additives could improve the nutritional profile of bread without increasing the risk of biogenic amine formation.     

Tempeh flour from chickpea (Cicer arietinum L.) nutritional and physicochemical properties

The effects of solid state fermentation (SSF) on physicochemical and nutritional properties of chickpea flour were studied. Fermented (tempeh) flour showed higher particle size index, gelatinization temperature, dispersability and resistant starch content, and lower gelatinization enthalpy and water solubility than unfermented flour. SSF increased the content of the essential amino acids (EAA) Ile, total sulphur (Met + Cys), total aromatic (Phe + Tyr), and Thr in 37, 41, 107, and 39 g kg⁻¹ protein, respectively; Trp content decreased 8 g kg⁻¹ protein. Total sulphur (EAA score = 0.87) was limiting in unfermented flour and Trp (0.93) in tempeh flour. SSP improved the in vitro and true protein digestibility (72.2–83.2% and 83.7–88.8%, respectively), protein efficiency ratio (PER, 1.59–2.31), cPER (1.54–2.21), and corrected protein digestibility (0.73–0.89). Chickpea tempeh flour may be considered for the fortification of widely consumed legume-based food products.     

Physical and functional characteristics of selected dry bean (Phaseolus vulgaris L.) flours

Many varieties of dry beans (Phaseolus vulgaris L.) are available with entirely different physico-chemical and sensory characteristics. Selected dry bean varieties (red kidney, small red kidney, cranberry and black) were processed into flour and analyzed for the physico-chemical and functional characteristics. The bulk density of the beans flours varied significantly (p < 0.05) from 0.515 g/ml for black bean flour to 0.556 g/ml for red kidney bean flour. The small red kidney bean flour had the highest water absorption capacity (2.65 g/g flour) while black bean flour showed the lowest at 2.23 g/g flour. Significant differences were observed for oil absorption capacities of bean flours, which ranged from 1.23 g/g for small red kidney bean flour to 1.52 g/g for red kidney bean flour. The bean flours emulsion capacity and stability and foaming capacity and stability also varied significantly and was variety-dependent. The highest apparent viscosity, 0.462 Pa.s, was recorded for small red kidney bean flour whereas black bean flour exhibited the lowest value of 0.073 Pa.s at 30 g/100 ml water content in the flour dispersions. The force-deformation curves for doughs from different bean flours showed that black bean flour had the highest peak force or hardness value of 90.7 N followed by doughs from cranberry, small red kidney and red kidney bean flours. The results of this study offer useful data on bean flours' potential uses in different food products.