Proximate Composition and Functional Properties of Fullfat and Defatted Beniseed (Sesamum Indicum L.) Flour

The proximate composition and functional properties of fullfat and defatted beniseed (Sesamum indicum L.) flour were evaluated. Functional properties studied were foam capacity and stability, water and oil absorption, bulk density, emulsion capacity and nitrogen solubility. Defatting increased the crude protein, ash, crude fiber, carbohydrate and mineral contents. Defatted flour showed comparatively better foam capacity and stability, water absorption and emulsion capacities but diminished bulk density and oil absorption capacity. Nitrogen solubility was pH dependent with a minimum at pH 4 and maximum at pH 8. Maximum nitrogen solubility (95%) was recorded for defatted flour while that for the fullfat flour was 60%. The proximate composition and functional properties of the samples suggest that beniseed flour would have useful application in fabricated foods.     

Influence of pH and sodium chloride on selected functional and physical properties of African breadfruit (Treculia africana Decne) kernel flour

African breadfruit seeds were cleaned, parboiled (98 ^°C) for 15min, drained and dehulled. The kernels were sun-dried, then milled andsieved into flour. Nitrogen solubility (NS), water absorption capacity(WAC), emulsion activity (EA), viscosity, foaming and emulsifyingproperties of the flour were determined as functions of pH and NaClconcentration. The NS was pH dependent with a minimum at pH 4 andmaximum at pH 10. The flour also exhibited minimum and maximum foamcapacity at pH 4 and 10, respectively. The minimum emulsion activity wasat pH 4, a value which increased from 7–16% at pH 12. The addition ofNaCl at concentrations of 0.2 to 0.4 M improved WAC, NS, foamingand emulsion properties of the flour. Sodium chloride enhanced NS of theflour at pH 4–6 and EA at pH 2–8.The EA at pH 2, 10 and 12 correlated negatively (r = –0.30) with NaClconcentration levels; however, the correlation was not significant (p> 0.05). The flour dispersions had lower viscosities at acid pH and in thepresence of NaCl than at neutral and alkaline pH values. Results indicatedthe flour could be used in food product supplementation.     

Proximate composition and selected functional properties of fermented and unfermented African oil bean (Pentaclethra macrophylla) seed flour

Flour samples were prepared from fermented and unfermentedAfrican oil bean (Pentaclethra macrophylla) seeds (AOBS). The flour samples were evaluated for proximate composition and certain functional properties. The influenceof defatting on these properties was also determined. Fermentation significantly increased (p<0.05) the proteinand decreased the crude fiber, ash, fat and carbohydrate contents of the AOBS flours. The nitrogen solubility of both fermented and unfermented flours was pH dependent withminimum and maximum solubility at pH 4.0 and pH 8.0, respectively, and with increased nitrogen solubility in the fermented sample. The fermented and unfermented flour sampleshad least gelation concentrations of 14 and 16% (w/v), respectively. The water absorption capacity and foam capacitiesof the fermented flour were 36 and 34%, respectively, over the unfermented seed flour. On the other hand, fermentation decreased the fat absorption capacity, emulsion activity and emulsion and foam stabilities. Fermentation decreased (p<0.05) the bulk density of AOBS flour by 15%. Defattingimproved all the functional properties evaluated except emulsion activity. These results indicate potential food usesof fermented and unfermented AOBS flour samples as protein supplements in diets and as functional ingredients in formulated foods.     

Certain functional properties of defatted pumpkin seed flour

Defatted pumpkin (C. pepo andC. maxima) seed flour has potential food uses because of its high protein content, 61.4±2.56%. The functional and electrophoretic properties of the defatted flour were investigated. Polyacrylamide gel electrophoresis and electrofocusing indicated 14 bands of water-soluble protein subunits with isoelectric points between 3.81–8.08 and apparent molecular weights between 19,200 and 97,000 daltons. Minimum nitrogen solubility was observed at pH values between 3.0–7.0 and exceeded 90% at pH above 9.0. Solubility was a function of ionic strength. It appeared that, even at the pH of minimum solubility, the pumpkin seed proteins could be dissolved up to high concentrations by increasing NaCl molarity. The viscosity of flour-water dispersion was affected by flour and salt concentrations, and temperature. The least gelation concentration was 8% (w/v) and the water and oil absorption 24.8±2.03 and 84.4±4.05 g/100 g respectively. Sorption isotherms, BET monolayer moisture and binding energy of sorption were also calculated. Both foam capacity and stability were pH dependent.     

Changes in the concentration of avenanthramides in response to salinity stress in CBF3 transgenic oat

Oat avenanthramides have long been known to possess potential nutraceutical and therapeutical properties. The change in avenanthramides 2p, 2c and 2f concentration in four salinity tolerant transgenic oat plants containing CBF₃ gene and non-transgenic control exposed to different levels of salinity stress was investigated. Determination of oat avenanthramides at the nano-scale level was performed using a well-optimized and highly sensitive sequential injection chemiluminescence (SIA-CL) method enhanced by eco-friendly gold nanoparticles biosynthesized from oat biomass extract. Under the conditions of this study, the predominant avenanthramide, which also exhibited the strongest scavenging capacity, was 2c followed by 2p and 2f. At no stress, there was no significant (p ≤ 0.05) difference between the transgenic lines and control regarding the concentrations of the three determined avenanthramides. After exposure to 250 mmol L⁻¹ NaCl, avenanthramide 2c dramatically increased by 170.9%, 580%, 353.6%, 457.6% and 229.1% in the control and the four transgenic lines, respectively. Among the transgenic lines, Agrogle-1 maintained the highest avenanthramides concentration under all salinity levels with maximum values of 71.5 mg kg⁻¹ for 2p, 221.0 mg kg⁻¹ for 2c and 62.0 mg kg⁻¹ for 2f detected at 250 mmol L⁻¹NaCl. The results of this study demonstrated that oat avenanthramides might have a potential role in enhancing abiotic stress tolerance in oats.     

Effects of debittering methods on the proximate composition,organoleptic and functional properties of sesame (Sesamum indicum L.) seed flour

Sesame seeds were boiled and allowed to sprout under ambient condition (30±2 °C) with an objective to reduce or eliminate the bitter taste associated with them. The untreated seeds were used as a control. The proximate composition, functional and organoleptic properties of defatted sesame flour were assessed at room temperature. There was a slight increase (about 10%) in protein content of sprouted seeds. The foaming capacity of flours from untreated, sprouted and boiled seeds were 34.6, 38.5 and 11.5%, respectively. The flour from the boiled seeds had the highest foam stability. Flours from untreated or sprouted seeds, gelation started at the least concentration of 6% whereas that from boiled seed was 11%. The emulsion capacity of flours from the untreated or sprouted seeds was the same (27.6 g oil/g sample) while that from boiled seeds was 12.9 g oil/g sample. Emulsion stability with prolonged storage appeared to be more with flours from the sprouted or boiled seeds than that from the untreated ones. The water absorption properties of flours from the untreated, sprouted and boiled seeds were 8.0, 5.9 and 6.5 g H₂O/g sample, respectively whereas the oil absorption capacity same (5.9 g oil/g sample). The bitter taste in flours from the untreated or sprouted was high. The bitter taste was not detected in flour from boiled seeds and the functional properties of the flour were not deleteriously affected except foaming and emulsion capacity. Therefore, this boiling method of debittering sesame seed could be practised. The quality of sesame flour obtained with this boiling method could still serve its role in traditional dishes and in the formulation of some other conventional food products.     

Extrusion process improves the functionality of soluble dietary fiber in oat bran

Extrusion processing is a thermal process applied to food preparation. However, its effects on food ingredients are ambiguous. The aim of this study was to elucidate the effects of extrusion processing on soluble dietary fiber (SDF) in oat bran. The yield, composition, thermal properties, rheological behavior and functionality of SDF in extruded oat bran were compared with those of SDF in untreated oat bran. The results showed that SDF in extrude oat bran had higher yields (14.2%), mean particle diameter (1718.1 nm), peak temperature (T_p = 69.0 °C), solubility, swelling capacity, solvent retention capacity, foam ability, apparent viscosity and consistency coefficient, and lower flow behavior index than those of SDF in untreated oat bran. The extrusion process improves some properties of SDF from oat bran.     

Changes of β-glucan physicochemical characteristics in frozen and freeze dried oat bran bread and porridge

The ability of oat foods to lower serum cholesterol and post-prandial blood glucose concentrations has been linked to the physicochemical properties of the bioactive component, mixed linkage β-glucan. Oat foods frequently need to be shipped or stored prior to analysis and β-glucan characteristics may change over time. Reductions in β-glucan solubility or molecular weight lead to lower viscosity development which decreases bioactivity. Impact of freezing and freeze drying conditions on the β-glucan physicochemical characteristics in oat bran bread and porridge were studied. Two in vitro digestibility methods were used to produce physiological extracts and the results were compared. The β-glucan molecular weight, solubility and viscosity for oat bread stored at room temperature were unchanged for 3 days, followed by a gradual decline in these parameters. The extract viscosity for bread decreased significantly after freezing at −80 °C and freeze drying after freezing at −18 and −80 °C, whereas freezing in liquid nitrogen did not significantly influence viscosity. Freezing of oat bran porridge did not affect extract viscosity, but freeze drying resulted in reduction of extract viscosity compared to the fresh porridge. Freezing and freeze drying did not dramatically affect the molecular weight or solubility of β-glucan in either product. The rapid visco analyzer was more effective and reliable for sample digestion than when physiological extraction was conducted in the shaking water bath. Generally, freezing at −18 °C or by submersion in liquid nitrogen maintained the physicochemical characteristics of β-glucan in food products either for commercial products or subsequent analysis.     

Functional properties of protein from Lesquerella fendleri seed and press cake from oil processing

This investigation determined the functional properties of protein in Lesquerella fendleri seed and press cake from oil processing. L. fendleri seeds were heat-treated at 82 °C (180 °F) during 120 min residence time in the seed conditioner, and then screw-pressed to extract the oil. Unprocessed ground, defatted lesquerella seeds and press cakes were analyzed for proximate composition and protein functional properties. Protein from unprocessed lesquerella seed showed the greatest solubility (≥60%) at pH 2 and 10 and was least soluble (25%) at pH 5.5–7. Unprocessed lesquerella protein also had high surface hydrophobicity index (S_o), as well as, excellent foaming capacity and stability, emulsifying properties, and water-holding capacity (WHC) at pH 7. Protein solubility profile of the press cake showed up to 50% reduction in soluble proteins at nearly all pH levels, indicating heat denaturation during cooking and screw-pressing. Foaming capacity of the press cake protein decreased slightly, but foam stability was completely lost. Press cake protein also had markedly reduced values for S_o, emulsifying properties and WHC, further confirming lesquerella protein’s sensitivity to heat treatment.     

Improvement on functional properties of wheat gluten by enzymatic hydrolysis and ultrafiltration

Four fractions (100-, 50-, 20-K and permeate) from a proteolytic hydrolysate (DH=2.8%) of wheat gluten were separated using size fractionation on ultrafiltration membranes with molecular weight cut-offs of 100, 50 and 20 kDa and their functional properties evaluated. Proteolysis led to a significant (P<0.05) increase in solubility of gluten fractions at pHs between 2–10 and a shift of the pI value from 6–7 to 5. The solubilities of 100-K, 50-K, 20-K and permeate fractions were significantly (P<0.05) improved compared with the untreated control and the hydrolysate. The 50-K fraction was superior to other three fractions for emulsion activity index between pH 2 and 10. The most stable foam was given by the 100-K fraction which showed 65.8% of initial foam while the control sample gave only 23% of foam, after 60 min resting. Foam stability decreased as the molecular mass of hydrolysate fractions decreased. Furthermore, after proteolysis, the surface hydrophobicity (H₀) of gluten increased significantly (P<0.05) compared with the control except for the permeate fraction. The highest value of H₀ was given by the 100-K fraction, followed by the 50-K, 20-K and permeate fractions. In addition, proteolysis resulted in a decrease in the storage modulus of gels.     

Characterization of a gluten reference material: Wheat-contaminated oats

Oat could be a good addition to the Gluten Free diet, but the purity of the oat supply is under scrutiny. As celiac disease becomes more prevalent, better detection tools for gluten in oats are necessary. We aimed to produce reference materials (RMs) of Canada Western Red Spring wheat (CWRS)-contaminated oat flour. Pure, uncontaminated oats flour (cultivars Navan and Gehl) was supplied by Cream Hill Estates. CWRS samples were provided by the Canadian Grain Commission from the 2009 Harvest Sample program. RMs containing 0, 20 and 100 ppm CWRS gluten-contaminated oats were created using a V-shell blender and tested by sandwich-type ELISA for gluten. Marked variations in ELISA results for the RMs were found among different test kits due to differences in capture antibodies and kit construction. The Veratox test was accurate at the 0, 20 and 100 ppm levels but detected only 30% (Veratox) and 50% (Veratox R5) of gluten at the 1000 ppm level; the Ridascreen test was accurate at all levels; the Biokits test detected roughly 10% of the gluten dosage; the Gluten-Check test detected some 30% of the gluten dosage. The RMs created could serve as standards for gluten detection in oat containing foods.     

Compositional,functional and storage properties of flours from raw and heat processed African breadfruit (Treculia africana Decne) seeds

African breadfruit (Treculia africana Decne) seeds were either boiled or roasted and then milled into flour. Chemical composition, functional properties and storage characteristics of raw and treated flours and the effect of partial proteolysis on selected functional properties of the raw flour were determined. Raw flour contained 20.1% crude protein, 2.5% total ash and 13.7% fat. Heat processing significantly (p<0.05) improved in vitro protein digestibility, and water and fat absorption capacities but decreased bulk density, nitrogen solubility, emulsion and foaming properties, trypsin inhibitor, and phytic acid and polyphenol contents of the samples. Boiling proved more effective than roasting for improving protein digestibility, emulsion capacity and foam stability and reducing antinutritional factor levels. Partial proteolysis increased nitrogen solubility, bulk density and water and fat absorption capacities but decreased foam capacity at hydrolysis levels greater than 35%. Fatty acid and peroxide values of the samples increased during storage. Compared to raw samples, heat processed samples had significantly (p<0.05) lower and more acceptable peroxide values and free fatty acid contents and higher and more stable water (3.0 g/g sample) and fat (2.4 g/g sample) absorption capacities.     

Continuous Spectrophotometric Assay and Properties of Ascorbic Acid Oxidising Factors in Wheat

A continuous spectrophotometric assay was developed to measure ascorbic acid oxidation in crude Na₂SO₄ extracts of flour. The rate of ascorbic acid oxidation in flour extracts measured using this method was similar to the rate in flour-water suspensions and 2–4 fold less than the rate in dough measured using an indophenol-xylene extraction method. Flour extracts appeared to contain two ascorbic acid oxidising factors; one with optimal activity at pH 6·3 and 30 °C and the other with optimal activity at pH 10 and 40 °C. The pH 6·3 factor had properties similar to those of ascorbate oxidase (EC 1·10·3·3) in its pH and temperature stability, strong inhibition by NaN₃, KCN and diethyldithiocarbamate, inactivation by proteases, and greater stereospecificity towards -ascorbic acid than -isoascorbic acid. The pH 6·3 factor was most concentrated in the pollard milling fraction of wheat and was lowest in flour. The pH 10 factor had several properties indicating non-enzymic oxidation of ascorbic acid; it was not inactivated by proteases, it was inhibited poorly or not at all by the above ascorbate oxidase inhibitors, and it had low specificity for stereoisomers of ascorbic acid.     

Evaluation of sorghum flour as extender in plywood adhesives for sprayline coaters or foam extrusion

This study was conducted to evaluate sorghum flour as protein extender in phenol-formaldehyde-based plywood adhesive for sprayline coaters or foam extrusion. Defatted sorghum flour, containing 0.2% (db) residual oil and 12.0% (db) crude protein, was analyzed for solubility and foaming properties. Sorghum flour proteins were least soluble (≤12%) under acidic pH, most soluble (72%) at pH 10, and produced substantial and highly stable foam at pH 10. Sorghum flour was substituted (on protein content basis) for wheat flour in the standard glue mix. Mixing properties and bond strength of the sorghum-based glue were compared with those of the industry standard glue. The sorghum flour-based adhesive had mixing properties and appearance that were superior to those of the standard wheat flour-based plywood glue, but its viscosity and bond strength were markedly less. Doubling the amount of protein contributed by sorghum flour in the glue mix markedly improved both viscosity (1104 cP) and adhesion strength (1.37 MPa) of the sorghum-based plywood glue to acceptable levels. The modified sorghum flour-based plywood glue also produced foam that remained stable up to 3 h. These results demonstrated that sorghum flour is a viable extender in plywood glues for sprayline coater or foam extrusion.     

Understanding the role of oat β-glucan in oat-based dough systems

B-glucan is one of the components that differentiate oats from other cereals and that contribute to the health-related value of oats. However, so far oats cannot easily be applied in bread-like products without loss of product quality. Here we have studied how the content and viscosity of oat β-glucan affect the technological properties of oat dough in both a gluten-free and a gluten-containing system. In both systems, increasing the β-glucan concentration resulted in an increase of dough stiffness and in a reduction of dough extensibility. β-glucan negatively impacted the elastic properties that additional wheat gluten conferred to oat dough. This effect was smaller for medium-viscosity β-glucan than for high-viscosity β-glucan. Interestingly, dough made from low β-glucan flour (<2%) had increased gas retention capacity. Overall, the impact of β-glucan on the properties of oat dough systems was governed by concentration and viscosity, with or without additional wheat gluten. Our findings indicate that β-glucan is a key component that determines the rheology of oat-based dough systems and, with that, the technological functionality of oat in dough systems.     

Development of a standard test for dough-making properties of oat cultivars

Bread is consumed all over the world. However, so far, production of large volume bread is only possible with wheat. Alternatives, such as oats, are less suitable but this is partly due to the lack of knowledge about their functionality for other purposes than porridge, which is their most common use. Existing standard tests for the dough making characteristics of wheat flour are not suitable for oat flour, hampering research to optimize oats for bread-making purposes. We therefore set out to develop a test to evaluate oat in relation to mixing and dough making properties using wheat as a model. It was possible to reproduce the profile of various qualities of wheat flour using mixtures of oat flour and gluten in different proportions. Our standard test was based on a dough system composed of 87.2% oat flour and 12.8% gluten and it presented similar properties to a wheat flour with regard to resistance to extension. This dough system was sensitive and reliable (coefficient of variation lower than 10%) for detecting differences among oat cultivars, and it can be used to screen oat varieties and individual oat components in relation to relevant properties for bread-making purposes.     

Effect of stir-frying on oat milling and pasting properties and rheological properties of oat flour

Stir-frying, similar to roasting, is a key step for oat milling process in China. The oat flour milling yield of Bayou No.2 and Bayou No.8 and their corresponding flour quality were investigated under different processing conditions (160 °C, for 0, 10, 20, 30 and 40 min). Results showed that oat flour milling yield was increased after stir-frying, Bayou No.2 and Bayou No.8 reached the highest yield after a 10 min and 20 min of stir-frying, which were 45.40% and 52.96%, respectively. With the increasing of stir-frying time, the gelatinization degree and the particle size of oat flour gradually increased, while their angle of repose and L* values were reduced. RVA studies showed that the stir-fried oat flour exhibited lower peak, trough, breakdown and setback viscosities compared to not stir-fried oat flour, indicating that stir-fried oat flour formed a more stable network structure and stir-frying induced an inhibitory effect on the retrogradation of oat flour paste. Rheological analysis suggested that the low tanδ of stir-fried oat flour than that of not stir-fried oat flour, revealing that the stir-fried oat flour paste exhibited more elastic but less viscous behavior.     

Effect of gaseous ozone treatment on the microbial and physicochemical properties of buckwheat-based composite flour and shelf-life extension of fresh noodles

In recent years, the application of gaseous or aqueous ozone in the processing of flour and noodles has been reported. However, little information is available about buckwheat-based (buckwheat-wheat-gluten) composite flour treated with gaseous ozone and fresh noodles made from the flour. This study investigated the microbial count, and physicochemical properties of buckwheat-based composite flour treated with gaseous ozone at 2.4 g h⁻¹ for 0, 2.5, 7.5 and 15 min and the shelf-life of fresh buckwheat noodles made from ozone-treated buckwheat-based composite flour (OTBF). Gaseous ozone significantly (p < 0.05) reduced the microbial total plate count and increased the CIE L* value, water absorption, development time, and stability time of the OTBF. The peak viscosity, final viscosity, setback, swelling capacity and solubility of the flour were also enhanced by ozone treatment. Scanning electron microscopy showed that ozone treatment facilitated the formation of more clumps and exposure of starch granules in the composite flour. In addition, gaseous ozone treatment at 2.4 g h⁻¹ for 15 min significantly suppressed microbial growth and reduction of L* value, maintained the overall sensory acceptability during the whole storage period, and the shelf-life of fresh noodles prepared from ozone-treated flour was extended to 96 h.     

Alpha-amylase treatment increases extractable phenolics and antioxidant capacity of oat (Avena nuda L.) flour

In this work, α-amylase was used to treat oat flour with the intent to release phenolic compounds with known antioxidant properties. After methanol extraction, the amounts of nine beneficial phenolic compounds were measured using HPLC. The antioxidant activities of the extracts were assessed using 2,2′-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) (ABTS)，2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and protein oxidative damage protection assays. Compared with heating-only treated oat flour, that treated with α-amylase showed significant increase of extractable total phenolic content (0.46–1.35 μmol gallic acid equivalents per gram oat), total antioxidant capacity, and an increased ability on the protection of protein from oxidative damage. Heating-only increased caffeic acid and vanillin content by 17 (0.03 vs 0.54 μg/g oat) and 1.8 (0.62 vs 1.11 μg/g oat) folds, but slightly increased the content of other phenols. Excluding heating effect, α-amylase treatment increased gallic acid content by 2.6 folds (0.38 vs 1.38 μg/g oat), caffeic acid content by 2.4 (0.54 vs 1.82 μg/g oat) folds, and other phenols by 1.0–1.8 folds. In conclusion, α-amylase treatment can yield oat products containing more extractable phenolic compounds with increased antioxidant capacity.     

Water extractable (1→3,1→4)-β-d-glucans from barley and oats: An intervarietal study on their structural features and rheological behaviour

The fine structures and rheological behaviours of aqueous flour dispersions and of β-glucan, (1→3,1→4)-β-d-glucan isolates obtained from 18 registered varieties of normal covered barley seeds and four registered oat varieties, grown in the same location in Greece, were investigated. The β-glucan content of the barleys and oats varied between 2.5–5.4 and 2.1–3.9%, respectively (dry matter basis). Heat treatment of the barley and oat flour dispersions with 80% (v/v) ethanol, to inactivate endogenous β-glucanases, had a stabilizing effect on the viscosity profile of the flour slurries. The relationship between total β-glucan content and aqueous slurry viscosity (at 247 s⁻¹) of the heat-treated barley flours was weak (r²=0.45, p<0.05, n=18). β-Glucans were isolated by water extraction at temperatures slightly below the gelatinization temperature of starch, enzymatic removal of starch and partial removal of contaminating proteins by adjustment to pH 4.0–4.5, and subsequent precipitation of the water-soluble β-glucans with 80% (v/v) ethanol. The cellulosic oligomers released by the action of a (1→3,1→4)-β-d-glucan hydrolase showed cellotriosyl and cellotetraosyl units, accounted for 91.1–92.1% for barley and between 92.4 and 94.1% for the oat preparations; the respective molar ratios of tri- to tetra-saccharides (DP3/DP4) ranged between 2.73–3.05 (barley) and 2.16–2.42 (oat). Steady shear measurements confirmed the random coil type behaviour of freshly prepared β-glucan solutions (5 and 7%, w/v). The rate at which shear thinning began was dependent on both concentration and molecular size of the polysaccharide. Most of the β-glucan dispersions followed the Cox–Merz rule, except Mucio, a variety with high M_w β-glucan (2.39×10⁵). Viscoelastic characterization, at 8% (w/v), of three barley β-glucan aqueous dispersions differing in molecular size, indicated that the low molecular weight sample exhibited shorter gelation time and higher gelation rate (I_E=[dlog G′/dt]_max) than its higher molecular weight counterparts. Small deformation oscillatory measurements on gels of all barley β-glucan isolates (10% (w/v), 7 d storage, 25 °C) revealed a strong negative relationship (r²=0.88, p<0.01) between G′ (1 Hz, strain 0.1%) and apparent M_w of the polysaccharide.