Tension of oil-water interface and properties of O/W emulsions in dependence of faba bean globulins

Compared with faba bean globulin the improved flow, gelifying, surface and emulsifying properties of aqueous solution of the corresponding acetylated derivatives are reflected in O/W emulsions by their enhanced stability.     

Interfacial behaviour of succinylated faba bean legumin at low ionic strength

Changes in the tensio-active properties of the main storage protein from faba beans (legumin) after succinylation were studied at a low salt concentration. Surface tension, surface dilatational properties of monolayers and emulsifying activity were measured at a ionic strength of I = 0.02. The results were compared with those at a high ionic strength of I = 0.3. Parameters of the Gibbs' adsorption isotherm indicate that the most surface-active derivatives are legumins with a moderate degree of succinylation (34% and 65%). The equilibrium surface pressure, π_e, inreased from 18.47 (native legumin) to 20.72 mN/m (65% succinylation). The critical association concentration, CAC, i. e., the subphase concentration at which the plateau of π_e was reached, decreased from 15.9·10^–6 to 7.12·10^–6 g/ml after 34% succinylation. The film forming properties differed from the adsorption behaviour. Only monolayers of the 65% succinylated legumin exhibited viscoelastic behaviour. By contrast, the emulsifying activity, EAI, reached the highest values for the 65% and 95% succinylated legumins. Low salt concentrations favour the adsorption of the native legumin and reduce the surface activity of succinylated legumin. Monolayer formation and especially the ability to form elastic networks seems to be diminished by the repulsive interaction of like-charged molecules. The emulsifying properties of the higher succinylated legumins are not influenced by the ionic strength whereas those of the native and low succinylated legumin are distinctly lower at I = 0.02. This result points to different adsorption and stabilizing processes during emulsion formation.     

Functional and electrophoretic characteristics of faba bean (Vicia faba) flour proteins as affected by germination

Faba beans (Vicia faba) were germinated at room temperature for 3 and 6 days respectively. The effect of germination on the protein fractions, protein solubility index, PAGE pattern and some functional properties i.e. emulsification capacity (EC), foaming capacity (FC), foam stability (FS), water and fat absorption capacities of the flour was studied. Germination decreased albumins, globulins and prolamins at different levels but non protein nitrogen and glutelins were increased. The protein solubility index was high at both extreme pH values with an isoelectric point (IP) at pH of 4.4-4.5. The solubility of the protein slightly increased due to germination at all the pH values. PAGE pattern revealed on obvious dissociation and utilization for both fast and slow moving protein fractions during germination. Emulsification and foaming properties vs pH profile were similar to the pattern of solubility vs pH. Both properties were high at acidic and alkaline pH's and the minimum values were at pH 4 to 5. Germination process improved EC, FC and FS of the flour in comparison with that of dry bean flour. Water absorption of faba bean flours was improved during germination but the fat absorption markedly decreased.     

A method for the characterization of breakdown/reforming behaviour of faba bean protein dispersions

The present paper is concerned with the Doherty/Hurd method [1] for the investigation of the influence of NaCl, CaCl₂ and pectin on the structural breakdown/reforming behaviour of dispersions containing acetylated faba bean protein isolate (AFBPI).     

Protein content variation in a pure line faba bean (Vicia faba) collection

A set of 840 pure line faba beans (Vicia faba L) derived by a process of cyclic single plant selection from 1979 to 1985 was used for this study. Mean content of protein was 240 g kg^?1 with a standard deviation of 18 g kg^?1 and a range of 180 to 310 g kg^?1. For eight subregional groups (Nile Valley, West Asia, Northern Europe, Southern Europe, Eastern Europe, North Africa, Ethiopia and the Indian subcontinent) and for a large and small grouping, the means and ranges of protein content were similar. There were no significant correlations between protein content and seed yield or its components. This resulted in a strong correlation (significant at P < 0.01) between seed yield and protein yield (r = 0-98), supporting the hypothesis that the optimal way to increase sustainable protein yield per hectare is to increase and stabilise seed yield.     

Structure of faba bean, black bean and pinto bean starches at different levels of granule organization and their physicochemical properties

The structure and physicochemical properties of pulse starches isolated from different cultivars of faba bean (FB), black bean (BB) and pinto bean (PB) were examined. FB starches exhibited numerous cracked granules, whereas the surface of PB and BB starches showed no evidence of cracks or indentations. Apparent amylose, phosphorus and bound lipid contents ranged from 25.8 to 33.6%, 0.004 to 0.009% and 0.13 to 0.15%, respectively. Variations in the above parameters among cultivars of FB and BB were marginal, but significant (P < 0.05) among cultivars of PB. All starches exhibited a ‘C’ type X-ray pattern. The amount of B-type unit cells ranged from 20.6 to 25.0% (FB), 15.4 to 17.7% (BB) and 7.9 to 17.3% (PB). Relative crystallinity ranged from 20.3 to 21.9% (FB), 20.4 to 21.3% (BB) and 21.3 to 23.1% (PB). Molecular order near the granule surface followed the order: BB ~ PB > FB. Variations in molecular order among cultivars of FB, BB and PB were marginal. Differences in amylopectin chain length distribution among FB, BB and PB starches and among cultivars were marginal. The extent of interaction of amylopectin double helical associations within the crystalline lamella followed the order: BB ~ PB > FB. Amylose leaching (AML) in the temperature range 60–90 °C, gelatinization temperatures and enthalpy of gelatinization followed the order: FB > BB ~ PB, FB > PB > BB, BB ~ PB > FB and BB ~ PB > FB, respectively. Variations in AML among cultivars were marginal in FB, but significant (P < 0.05) in BB and PB starches. Swelling factor (SF) in the temperature range 60 to 85 °C and at 90 °C followed the order: FB > BB ~ PB and BB ~ PB > FB, respectively. Differences in SF among cultivars of FB and BB starches were more significant (P < 0.05) at temperatures below 80 °C, whereas, in PB starches, differences among cultivars were more significant (P < 0.05) at temperatures above 80 °C. Variations in peak viscosity, viscosity breakdown and set-back were marginal among FB cultivars, but were significant (P < 0.05) among BB and PB (PB > BB) cultivars. FB starches were hydrolyzed by 2.2 N HCl at a faster rate than BB and PB starches (BB > PB). The amounts of rapidly digestible starch (RDS), slowly digestible starch (SDS), resistant starch (RS), hydrolysis index (HI) and expected glycemic index (eGI) followed the order: FB > BB ~ PB, FB > BB ~ PB, BB ~ PB > FB, FB > BB > PB and FB > BB > PB, respectively. Variations in RDS, SDS, RS, HI and eGI among cultivars followed the order: PB > BB > FB. The in vitro digestibility studies showed that PB and BB starches may be more effective than FB starches in controlling blood glucose levels.     

Optimised processing of faba bean (Vicia faba L.) kernels as a brewing adjunct

Pulse (Fabaceae) grains, such as peas and beans, are derived from crops that are usually cultivated in the absence of mineral nitrogen fertiliser as these crops can obtain their nitrogen requirement naturally from the air via biological nitrogen fixation. Therefore, pulses present a significantly lower greenhouse gas (GHG) footprint than crops demanding nitrogen fertiliser, whilst also offering significant quantities of starch for the brewing and distilling industries. Mitigation of agriculture derived GHG emissions through utilisation of pulses can have a positive environmental impact. To this end, the potential of exploiting dry, dehulled faba bean (Vicia faba L.) kernel flour as an adjunct for beer production was evaluated. The impact of different temperature regimes and commercial enzymes were assessed for their effect on wort: viscosity; run‐off rate; primary amino nitrogen content and, fermentability. Faba beans demonstrated insufficient endogenous enzyme capacity for starch conversion and generated a viscous wort. However, using a stepped temperature mashing regime and exogenous enzyme additions, the faba bean wort was comparable in processability and fermentability to that of 100% malted barley wort. The faba based beer and co‐product qualities demonstrate the environmental, nutritional and commercial potential of pulses in brewing. © 2020 The Authors. Journal of the Institute of Brewing published by John Wiley & Sons Ltd on behalf of The Institute of Brewing & Distilling     

Sequential adsorption of egg-white proteins at the air–water interface suggests a stratified organization of the interfacial film

The aim of this work was to get further insight into the formation of the interfacial film by ovalbumin and lysozyme in equimolar binary solutions, as well as the organization of these proteins inside the interfacial film. Our approach consisted in the sequential adsorption of the two proteins, with or without previous replacement of the sub-phase with protein-free buffer before injection of the second protein.     

Arsenate adsorption mechanisms at the allophane-water interface

We investigated arsenate (As(V)) reactivity and surface speciation on amorphous aluminosilicate mineral (synthetic allophane) surfaces using batch adsorption experiments, powder X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). The adsorption isotherm experiments indicated that As(V) uptake increased with increasing [As-(V)]0 from 50 to 1000 microM (i.e., Langmuir type adsorption isotherm) and that the total As adsorption slightly decreased with increasing NaCl concentrations from 0.01 to 0.1 M. Arsenate adsorption was initially (0-10 h) rapid followed by a slow continuum uptake, and the adsorption processes reached the steady state after 720 h. X-ray absorption spectroscopic analyses suggest that As(V) predominantly forms bidentate binuclear surface species on aluminum octahedral structures, and these species are stable up to 11 months. Solubility calculations and powder XRD analyses indicate no evidence of crystalline Al-As(V) precipitates in the experimental systems. Overall, macroscopic and spectroscopic evidence suggest that the As(V) adsorption mechanisms at the allophane-water interface are attributable to ligand exchange reactions between As-(V) and surface-coordinated water molecules and hydroxyl and silicate ions. The research findings imply that dissolved tetrahedral oxyanions (e.g., H2PO42- and H2AsO4(2-)) are readily retained on amorphous aluminosilicate minerals in aquifer and soils at near neutral pH. The inner-sphere adsorption mechanisms might be important in controlling dissolved arsenate and phosphate in amorphous aluminosilicate-rich low-temperature geochemical environments.     

Toxicological evaluation of acetylated faba bean globulin

Acetylated faba bean globulin (acVFG, acetylation degree 97%) was evaluated toxicologically in a subchronic feeding study and a female fertility test. Groups of male and female rats received acVFG in their diet at levels of 20, 40 and 80 g kg⁻¹ for 3 months. Additional groups were fed a commercial diet or given food containing 38 or 75 g kg⁻¹ casein. The subchronic toxicity study revealed growth retardation in both sexes at the 80 g kg⁻¹ acVFG level. The food consumption was reduced in males at 40 and 80 g kg⁻¹ acVFG and in females at 80 g kg⁻¹ acVFG. Histopathological alterations in the ovaries were observed at dietary levels of 40 and 80 g kg⁻¹ acVFG. Histopathological changes and decreases in the absolute and relative weight of the uterus were found in all groups fed acVFG. Therefore a no‐observed‐effect level (NOEL) was not derivable. Feeding females 80 g kg⁻¹ acVFG resulted in diminished pre‐implantation losses but increased post‐implantation losses in the fertility study. © 2000 Society of Chemical Industry     

Isolation of clean-label faba bean (Vicia faba L.) proteins: A comparative study of mild fractionation methods against traditional technologies

Plant protein isolation by mild wet processing methods that are free of alkali/acid and thermal treatments were investigated in order to address the fast growing consumer demand for clean-label ingredients. The impact of different mild wet fractionation conditions was established in terms of yield, purity and recovery of faba bean protein concentrates/isolates (PCs/PIs) from both Snowbird (low tannin, LT) and Athena (high tannin, HT) cultivars. Although salt-soluble globulins (74 to 75%) were the primary proteins found in faba beans, PIs resulting from dialysis (LT: 93.2 ± 0.1% and HT: 96.4 ± 0.3%) or micellization (LT: 99.1 ± 0.1% and HT: 98.7 ± 0.2%) following water extraction at 35 °C (W₃₅) at a solvent/feed (S/F) ratio of 2 had higher protein contents than PCs from aqueous NaCl extraction followed by dialysis (LT: 79.1 ± 0.1% and HT: 81.6 ± 0.5%) or alkali extraction followed by acid precipitation (LT: 87.1 ± 1.4% and HT: 86.3 ± 0.2%). These differences in protein extractability of water- and salt-based methods could be attributed to the high levels of endogenously present minerals. Although methionine and cysteine were limiting amino acids, the W₃₅ methods resulted in overall higher amino acid content and in high-quality PIs compared to the rest due to the presence of albumins as confirmed by SDS-PAGE. The W₃₅-PIs were low in raffinose family oligosaccharides, tannins and trypsin inhibitory activity and can be considered chemical-free alternatives to alkali extracted-acid precipitated PCs.     

Changes in interfacial behaviour, emulsifying and foaming properties of faba bean legumin after modification with dimethylsuberimidate

The effect of a rising rigidity and surface hydrophobicity of the 11S storage protein from faba beans--legumin--induced by chemical modification with dimethylsuberimidate (DMS) on some surface functional properties was studied. Short-time adsorption kinetics using a droplet-volume tensiometer, pressure transformation and desorption behaviour of monolayer using a film balance, and emulsifying and foaming properties were determined to characterize surface activity and interfacial film forming behaviour. Tensio-active properties at the air-water interface, i.e. decay in surface tension and pressure transformation in monolayer, were improved by modification. However, a decrease in emulsifying activity, foam capacity and foam expansion after modification of the legumin points to an overall deterioration of energy-induced film forming behaviour. The results support the view that surface activity is generally governed more by molecular flexibility than by surface hydrophobicity.     

Presence of two saponins in faba bean (Vicia faba L.) seeds

From faba bean (Vicia faba L.), two new saponins were isolated by Sephadex LH-20 gel filtration, ODS column chromatography and semi-preparative HPLC. Their molecular weights determined by FAB-MS were 978 and 962, respectively. Results of TLC and FTIR analyses showed that these compounds are similar to soya saponin group B. The presence of separated saponins was confirmed by TLC for seeds of four cultivars of faba bean.     

Cooking quality of faba bean after storage at high temperature and the role of lignins and other phenolics in bean hardening

Selected physical and chemical characteristics of faba beans (Vicia faba L.) cv. Fiesta were studied after 12 months storage at 5, 15, 25, 37, 45 or 50 °C (±2 °C) in relation to the hard-to-cook phenomenon. In comparison with control (seeds stored at 5 °C), seeds stored at 15 and 25 °C demonstrated non-significant (p?0.05) changes in most of the physical and chemical characteristics including hydration and swelling coefficients, acid detergent fibre, lignin and tannin contents, whereas seeds stored at ?37 °C demonstrated significant changes (p?0.05). Solutes and electrolytes leaching after 18 h soaking substantially increased with increased temperature. Faba bean hardness tested by the hard-to-cook test also increased substantially with increased storage temperature. After 8 h soaking followed by 2 h cooking, the puncture force required for seeds stored at 5 °C was 3.3 N seed⁻¹ whereas seeds stored at 50 °C required a much higher puncture force of 15.2 N seed⁻¹. There was a high negative correlation (r²=0.98) between storage temperature and cooking ability of faba bean. Substantial increases in acid detergent fibre and lignin contents occurred with increased storage temperatures. There was a three-fold increase in lignin content of faba bean stored at 50 °C compared to those stored at 5 °C and it was correlated with bean hardness (r²=0.98). Storage at high temperatures for 12 months led to a substantial reduction in total free phenolics especially in the testa and there was a greater reduction with increasing storage temperature. Reduction in free phenolics was negatively correlated (r²=0.75) with bean hardness.     

Properties of spray-dried and freeze-dried faba bean protein concentrates

Summary  A protein concentrate from faba bean seeds was prepared by isoelectric precipitation and spray-dried. Its functional properties were measured and the results obtained were compared to those from another concentrate prepared by the classical freeze-drying technique. The functional properties were found to be indistinguishable. However, the protein solubility profile was different depending on the preparation technique. Some antinutritional factors (trypsin inhibitors, tannins and phytates) were also analysed. Both protein concentrates showed lower concentrations of tannins and phytates than the seeds.     

Dynamic adsorption of beta-casein at the gas–liquid interface

The dynamic adsorption of beta-casein onto the air–water interface was experimentally studied in terms of the dynamic surface tension using the pendant bubble method. The experimental data was modelled based on two solutions: diffusion towards a planar interface (Ward and Tordai solution) and a new solution for diffusion to a spherical bubble surface. Both modelled predictions can fit experimental data of 10⁻⁶ M solution, except the early section where the surface tension remains constant. The similar values of fitting parameters in both models indicated a minimal effect of bubble size on the considered system. The fitting value of adsorption constant (especially in case of 10⁻⁷ M solution) demonstrated the limits of current models.     

Influence of acetylated faba bean protein isolate on the rheological behaviour of O/W emulsions (Short communication)

Acetylated faba bean protein isolate (AFBPI) is particularly suitable for the stabilisation of O/W emulsions in acid and neutral pH regions. An essential feature of the consistency of O/W emulsions stabilised with AFBPI is an attractive creamy texture and non-slimy mouthfeel [7]. The aim of the present paper was to investigate the influence of AFBPI with different degrees of acetylation on the rheological behaviour of neutral and acidified, freshly prepared, concentrated oil-in-water emulsions.     

Effect of nutritional status of faba bean (Vicia faba L.) on protein solubility profiles

A field experiment was carried out to study the effect of mycorrhizal inoculation. phosphorus and sulphur fertilization, under two water regimes, on protein solubility fractions of faba bean. The major protein fraction of faba bean was the globulin fraction that ranged from 69.5 to 78.1%. Phosphorus treatment significantly (P⩽0.05) increased the globulin fraction of faba bean seeds in the wet treatment but significantly (P⩽0.05) decreased it in the dry treatment. All fertiliser treatments significantly (P⩽0.05) increased the albumin fraction in the wet treatment, whereas only treatments of mycorrhiza, mycorrhiza+sulphur and mycorrhiza+phosphorus+sulphur significantly increased it in the dry treatment compared to control. With the exception of the treatment mycorrhiza+sulphur, all other fertilisation treatments showed prolamin contents of faba bean seeds, similar to that of the control in the wet treatment. The G₃-glutelin fraction of faba bean ranged from 8.9 to 14.4%. Treatments with sulphur, mycorrhiza and mycorrhiza+sulphur significantly increased the G₃-glutelin fraction, whereas phosphorus and mycorrhiza+phosphorus treatments significantly decreased it. The insoluble protein (residue) of faba bean ranged from 1.8 to 3.4%. Generally, fertiliser treatments significantly increased the insoluble protein in the wet treatment. With the exception of treatments mycorrhiza and mycorrhiza+sulphur, all other fertiliser treatments significantly increased the insoluble protein content in the dry treatment. Water regime significantly (P⩽0.05) affected the protein fractions.     

Acetylation of faba bean legumin: conformational changes and aggregation

The effect of progressive acetylation upon the conformation of the 11S globulin legumin from faba bean has been studied using chemical analysis, UV, fluorescence and CD spectroscopy, viscometry and analytical ultracentrifugation. The modification did not induce complete dissociation of the oligomeric protein. Only 30% of the protein was found to be a dissociated 3S subunit after excessive acetylation, whereas 70% was a dimeric legumin aggregate with a molecular mass of about 700 kDa. The aggregation of the highly modified legumin in high‐ionic‐strength buffer solution leads to soluble higher legumin oligomers. The acetylation resulted in a moderate molecular expansion of legumin due to a changed tertiary structure, whereas the far‐UV circular dichroism spectra did not provide definitive evidence of a decrease in domain‐stabilizing β‐sheet conformations in their secondary structure. © 2000 Society of Chemical Industry