Physico-chemical and enzymatic studies on acetylated protein isolates from faba beans (Vicia faba L.)

Selected physico-chemical properties of a faba bean protein isolate before and after being acetylated have been investigated using analytical ultracentrifugation, SE- and RP-HPLC, viscometry and hydrophobicity measurements using fluorescence probe techniques. The time course of relative chymotryptic hydrolysis rates was followed by means of the TNBS method and RP-HPLC analysis. The extensive decrease of the 11 S and 7 S protein components of the isolate in favour of a low molecular weight 2 S component after exhaustive acetylation is the proof of the dissociated state of the highly modified derivatives. Both the viscometric measurement and the study of proteolysis breakdown give arguments for a rather unfolded state both of the unmodified and the modified protein isolates. The course of relative chymotryptic hydrolysis rate points to a successive transition from a globular state into a more unfolded one depending on the degree of acetylation. Both the viscometric data and the hydrophobicity measurements revealed a conformational transition at about 60% N-acetylation. This level of modification corresponds to that where a sharp increase of OH-acetylation takes place.     

The relationship between maturity and quality of canned broad beans (Vicia faba L.)

Summary. This paper describes a co-operative investigation carried out by the Fruit and Vegetable Preservation Research Association and eight of its member firms to determine optimum maturity of broad beans for canning.
The results indicate that (a) there was no difference in flavour in canned broad beans harvested at tenderometer readings from 90 to 200, (b) there was a significant linear deterioration in texture as beans matured, (c) alcohol insoluble solids of raw and canned beans increased linearly as beans matured, (d) a linear relationship was found between tenderometer readings and sample size, (e) consumers equally preferred canned broad beans harvested at tenderometer readings of 120 and 160 and (f) optimum maturity of broad beans for canning from the data obtained was at a tenderometer reading of 136 using a 5 oz sample of raw beans.     

Limited tryptic hydrolysis of legumin from faba bean (Vicia faba L.): formation of an [unequal] subunit pattern

One-dimensional and two-dimensional SDS-PAGE and Hydrophobic Cluster Analysis (HCA) were used for investigating the course of limited tryptic hydrolysis of faba bean legumin. SDS-PAGE revealed the formation of an “unequal” subunit pattern, characterized by 30 and 50 kDa subunits, which could be related to the A- and B-type subunits of legumin. These subunits followed different pathways during the non-cooperative part of the tryptic hydrolysis. HCA revealed structural differences between the subunit types and gave arguments to predicted potential splitting sites. A- and B-subunits differ in extension and composition of the flexible segments as well as in the interior of the C-terminal side, as in the C-termini of the α-chains which confirmed the observed non-uniform hydrolysis pattern. The HCA plot demonstrated that the number and exposition of flexible surface elements was changed by limited hydrolysis. This result was discussed with regard to the influence of tryptic modification on the emulsifying properties of legumin.     

Carbohydrates of spring and winter field beans (Vicia faba L.)

The proportions of available and unavailable carbohydrate were determined in samples of eight varieties of field beans (Vicia faba L.). Available carbohydrate consisted of dextrins, water-soluble and insoluble starches and ethanol-soluble sugars; the unavailable carbohydrate fraction contained lignin, cellulose, hemi-cellulose and water-soluble polysaccharides. The component sugars of extracts and hydrolysates of all fractions except lignin were measured by anion-exchange, thin-layer and paper chromatography. Winter-sown beans contained 46 to 48% available and 19 to 20% unavailable carbohydrate, while spring-sown beans contained 30 to 42% available and 22 to 37% unavailable carbohydrate on a dry matter basis. Two of the spring-sown varieties were atypical in certain respects: Strubes had a high percentage of available carbohydrate (42.4%), similar to the level found in winter-sown beans, while Ackerperle had a high percentage of total carbohydrate (67.4%) but the lowest percentage of available carbohydrate (30.1%). The protein content of Strubes (30.2%) was typical of spring-sown varieties, but that of Ackerperle (27.7%) corresponded to the lower level of winter varieties.     

Phytate and total phosphorus content of field beans (Vicia faba L.)

Considerable variation was found in the phytate and total phosphorus contents of varieties, selections and genotypes of field beans (Vicia faba L.) The phytate phosphorus content of seeds taken from single plants of the variety Dacre indicated that large variations (1.93-4.03 g kg^?1), not significantly correlated with protein content, existed within an established variety. Although some variation in the ratio of phytate to total phosphorus was observed (0.40-0.60), highly significant correlation coefficients were obtained for total and phytate phosphorus contents. The significance of the results obtained is discussed in relation to the potential for improving the nutritive value of field beans by breeding for lower phytate content.     

Effects of micronising on the utilisation of field beans (Vicia faba L.) by the young chick

The major changes in the composition of field beans (Vicia faba L.) caused by micronising were as follows: the moisture content was reduced from 16.5 to 13.2%, the trypsin inhibitor activity reduced from 2.49 to 0.21 trypsin inhibitor units/mg dry matter and the available carbohydrate content raised from 40.6 to 50.2%. Growth and food consumption of broiler chicks from 1 to 2 weeks of age were not affected significantly when micronised beans replaced raw beans in their diets at a level of 300 g/kg. However, food conversion efficiency, apparent dry matter digestibility and nitrogen retention were significantly improved and pancreas size significantly reduced when the birds were fed the diet containing the micronised beans. The nitrogen-corrected metabolisable energy (m.e.) of the diet containing 500 g of micronised beans/kg (10.88 MJ/kg) was significantly higher than that of a diet containing 500 g of raw beans/kg (10.33 MJ/kg). It was calculated that the m.e. of the beans had been raised from 10.59 to 11.67 MJ/kg dry matter by micronisation. The improvement in nutritive value is attributed partly to the destruction of the trypsin inhibitor and partly to the increased availability of the carbohydrate fraction of the beans.     

In vitro starch digestibility of fresh and sun‐dried faba beans (Vicia faba L.)

Fresh and sun‐dried faba beans (Vicia faba L.) were cooked, stored for various times at 4 °C and analysed for available starch (AS), resistant starch (RS) and fibre‐associated resistant starch (FARS) contents as well as α‐amylolysis. Fresh beans required a shorter cooking time (25 min) than dried beans (158 min). Cooked fresh faba beans had a higher AS content than cooked dried faba beans. The AS content in both decreased during cold storage, with fresh beans showing a smaller decrease than dried beans with increasing storage time. Cooked fresh faba beans also had a higher total RS content than cooked dried faba beans, although a greater increase in RS content was recorded in the latter upon storage. Starch retrogradation was more prominent in cooked dried faba beans than in cooked fresh faba beans, as indicated by the consistently higher FARS content. The α‐amylolysis rate decreased with increasing storage time, i.e. long‐stored (72 h) cooked faba beans exhibited slower starch digestion, and differences were recorded between fresh and dried beans. The predicted glycaemic index ranged between 60.9 and 58.0% for cooked fresh faba beans and between 57.9 and 55.8% for cooked dried faba beans, which is suggestive of slow glucose release from starch in faba beans. Copyright © 2007 Society of Chemical Industry     

包装与贮藏温度对蚕豆采后品质的影响

为明确适宜于鲜食蚕豆采后贮藏的温度与自发气调包装材料,以无保鲜膜包装的蚕豆为对照,研究了(1.0±0.5)℃下聚乙烯(PE)、聚氯乙烯(PVC)、微孔(W)3种保鲜膜包装和(5±1)℃PE保鲜膜包装对蚕豆硬度、色泽、水分含量等品质指标的影响。结果表明,(1.0±0.5)℃下采用PVC保鲜膜包装的蚕豆品质优于其它处理,蚕豆贮藏28d,仍保持较好品质。     

Preparation of broad bean (Vicia faba L. minor) products Part 3. Pretreatment of broad beans and broad bean flour —processes and effects

For improving sensory, functional and other properties broad beans are pretreated in 3 different ways. The pretreatments include defatting or isoelectric washing of broad bean flour and hydrothermal treatment of whole dehulled broad beans. Every pretreatment process leads to particular advantages, described in this paper, although sensory improvements are found in all pretreated products.     

Relationships between adsorption and emulsifying of acetylated protein isolates from fabe beans (Vicia faba L.)

The influence of acetylation on surface adsorption and emulsifying properties of faba beans protein isolates (FBPI) was studied. Generally, acetylation improved the interfacial activity of FBPI. The plateau value of the Gibbs' adsorption isotherms measured with the Wilhelmy-plate was between 22.97 and 24.22 mN/m. The critical association concentration (CAC), i.e. the inflection point of the adsorption isotherms, was shifted from 2.06. 10^?5 to 5.35. 10^?7 g/ml with progressive acetylation. The dependence of the CAC on the degree of acetylation was found to be significant. For FBPI stabilized n-decane/water emulsions with varying volume fraction of oil (?) the emulsifying activity index increased from 166 to 593 m²/g whereas the droplet size decreased from 7.79 to 3.4 μm with acetylation. The correlation between emulsifying activity of FBPI and both degree of acetylation and adsorption behaviour was only significant for emulsions with ? 0.4.     

Effects of dehulling,soaking and germination on chemical composition,mineral elements and protein patterns of faba beans (Vicia faba L.)

The effects of dehulling, soaking and germination on the changes in general chemical composition, nine mineral elements and the protein patterns of whole faba beans were studied. Such pretreatments had a significant effect on the changes in the chemical composition of whole beans. Dehulling of beans significantly increased the contents of copper, zinc and potassium, while it significantly decreased the amounts of iron, manganese, phosphorus, calcium, magnesium and sodium compared with whole beans. Whole beans soaked for 12 h, followed by dehulling, had higher amounts of iron, copper, zinc, calcium and sodium, and quite a lower level of potassium, than unsoaked dehulled beans. All of the mineral elements except zinc were significantly increased on germination. No obvious changes in the electrophoretic pattern of faba bean proteins were observed as the seeds were soaked for up to 12 h. Extending soaking time for a further 4 h led to the disappearance of one band at the region of MW 67 KD. Germination of seeds for 3 days initiated disappearance of some bands while other new bands were observed.     

Cellulase inhibition by tannins in the testa of field beans (Vicia faba)

The testa of field bean varieties with coloured flowers contained 4–8 % tannin (measured as total phenolics) compared with less than 0.6 % in the testa of white flowered varieties. The tannin present in whole beans was almost entirely contained in the testa. The presence of high levels of tannin reduced in vitro digestibility and solubility in cellulase solutions of the testa and addition of high tannin testa decreased the solubility of cotyledon protein in acid pepsin. Water extracts of the testa from coloured-flower varieties inhibited the action of fungal cellulase and reduced the in vitro digestibility of white flowered testa and cellulose. A highly significant relationship (r= ?0.93***) was found between the tannin content and solubility in cellulase of testa for a range of 24 varieties. It is concluded that the effect of testa tannins on in vitro digestibility can be mainly attributed to their effect on cell wall digesting enzymes rather than an effect on protein solubility per se.     

Bioavailability of calcium and magnesium from faba beans (Vicia faba L var major), soaked in different pH solutions and cooked,in growing rats

The nutritive utilisation of calcium and magnesium from faba beans (Vicia faba L var major), soaked in different pH solutions and then cooked, was studied in growing rats. Prior to the cooking process the beans were soaked in acid (pH 2.6 and 5.3) or basic (pH 8.4) solutions. Processing of the bean seeds did not produce appreciable losses of Ca or Mg by solubilisation. Digestive utilisation of calcium was high and did not vary with the different processing conditions assayed. Metabolic utilisation of calcium was significantly improved by soaking and by soaking plus cooking. Both digestive and metabolic utilisation of magnesium were significantly improved by all the different processes assayed. The observed improvement in the nutritive utilisation of Ca and Mg was correlated with a higher weight gain of the animals but not with the content of these minerals in the femur and longissimus dorsi muscle. The higher dietary intake of cellulose, lignin and phytate found in the processed faba bean diets did not have a negative effect on the digestive utilisation of the minerals studied. Overall, soaking in basic solution plus cooking was the most effective treatment. The processing conditions studied were inexpensive and easily applied and have great potential for application at household or industry level for human and animal nutrition. Copyright © 2004 Society of Chemical Industry     

Effect of industrial process conditions of fava bean (Vicia faba L.) concentrates on physico-chemical and functional properties

Fava bean (Vicia faba L.) is a promising source of proteins and has a potential in industrial food applications. Processing of fava ingredients modifies proteins and their functional properties. This study established the complexity of the relationship between fava protein-associated reactions (protein hydrolysis and aggregation), physico-chemical properties (electric charge, solubility, and intrinsic fluorescence, thermal integrity) and functional properties (foam and emulsion). For this study, an air-classified fava protein concentrate (65% w/w protein d.b.) was processed using pH (2, 4, 6.4 and 11), temperature (55, 75 and 95 °C) and duration of treatment (30 and 360 min) to produce 36 modified fava concentrates. Processing resulted in protein hydrolysis at pH < 4, and protein aggregation at pH ≥ 6.4 at temperatures above 75 °C, which influenced foaming and emulsification distinctly owing to the differences in their stabilizing mechanisms. Despite these modifications, their physico-chemical and functional properties were primarily governed by the beverage application pH. The surprising interplay shown between properties encourages the need to dive further into the different protein/non-protein reaction and interactions that can occur in fava concentrate.Industrial relevanceThe functionalities of fava bean protein-rich ingredients were investigated in industrial beverage application systems (pH 4 and 7) after industrial relevant process conditions (pH: 2, 4, 6.4 and 11; temperature: 55, 75 and 95 °C, treatment duration: 30 and 360 min). Foam capacity (>100%) was very high for all ingredients at both pH applications (acidic or pH 4, and neutral or pH 7), while the foam stability changed according to the application pH. So-called foam-breakers were discovered in acidic application, while all ingredients maintained high stability in neutral applications. A similar instability was found for emulsification, since emulsion made with all ingredients in acidic application creamed immediately after production. Emulsions in neutral applications were homogenous with all ingredients, thus, emulsion capacities were equivalent to each other, but the storage stability was affected by the ingredient processing pH.     

The impact of processing on phytic acid,in vitro soluble iron and Phy/Fe molar ratio of faba bean (Vicia faba L.)

BACKGROUND: Faba bean is one of the important legumes in Asian countries. It is also a major source of micronutrients in many rural areas. Unfortunately, the bioavailability of iron from faba bean is low because it is present as an insoluble complex with food components such as phytic acid. The influence of soaking, germination and fermentation with the expectation of increasing the bioavailability of iron was investigated. RESULTS: Fermentation treatments were most effective in decreasing phytic acid (48–84%), followed by soaking at 10 °C after preheating (36–51%). Steeping faba beans for 24 h at 25 °C had the least effect on the removal of phytic acid (9–24%). With increased germination time at 30 °C, phytic acid progressively decreased from 9 to 69%. Most wet processing procedures, except soaking after wet preheating, caused losses of dry matter and iron (8–15%). In vitro iron solubility, as a percentage of total iron in soaked faba bean after dry preheating, was significantly higher than in raw faba bean (P < 0.05). Fermentation and germination did not have significant effects on the solubility of iron. CONCLUSION: The expected improvement of iron bioavailability levels due to lower phytic acid was not confirmed by increasing levels of in vitro soluble iron. Soaking, germination and fermentation can decrease phytic acid in faba bean. However, results from in vitro solubility measurement of iron showed little improvement of iron bioavailability in fermented and germinated faba beans over untreated raw faba beans (P < 0.05). It seems that componets of dietary fibre other than phytic acid are more important in binding iron. Probably, a complex association between dietary fibre and iron is the reason for the poor bioavailability of iron in faba bean. Copyright © 2009 Society of Chemical Industry     

Gelation of a broad bean (Vicia faba L. minor) protein fraction (prepared at pH 2) in dependence on some influencing factors

A protein fraction is prepared from broad bean protein isolate at pH 2 which forms gels in the acid pH range. The gels are fluid at high temperature and become strength when cooling. The gel strength increases with increasing pH, with increasing heat treatment, and with increasing protein concentration. Addition of calcium and dextrose sirup increases the gel strength whereas sucrose decreases it. The transparency of the gels decreases with increasing pH.     

Fractionation of plant material. IV.—Distribution of amino acid residues in fractions obtained from leaves of broad bean (Vicia faba L.)

The quantitative distribution of amino-acid residues amongst some fractions derived from broad-bean leaves was determined. Among the free amino acids, asparagine predominated and 3,4-dihydroxyphenylalanine (DOPA) was abundant. DOPA was absent from the protein fractions. Aggregated N recovery and amino acid composition resembled those found for leafy materials by previous workers. Material extracted by ethanol from the TCA-precipitated fraction resembled the bulk protein in molecular size and amino acid composition. A fraction not migrating during electrophoresis in phenol-acetic acid-water gave, on hydrolysis, amino acids presumed to be bound in neutral or weakly acid compounds, mostly of low molecular weight.     

Variation in the oil content and fatty acid composition of field beans (Vicia faba) and peas (Pisum spp.)

Oil content has been found to range from 1.2–1.9% in a wide range of diverse field bean (Vicia faba) cultivars, populations and selections and from 1.4–2.8% in a narrower range of pea cultivars. The ranges in fatty acid composition for beans and peas respectively were palmitic, 13.9–21.0% and 12.0–16.6%, stearic 2.2–3.5% and 2.5–4.2%, oleic 15.0–33.0% and 14.2–33.3%, linoleic 41.3–59.7% and 43.7–60.9%, linolenic 2.6–4.9% and 6.4–13.4%. Environment exerted a significant effect on the oil content of field beans but cultivar differences remained apparent. The analysis of whole or milled field beans stored for up to 5 years showed only minor losses of oil and component fatty acids. In both species over 90% of the total oil content was found in the cotyledons. Cultivar differences in whole grain oil content were associated with the concentration of oil in the cotyledons and appeared independent of the relative proportions of either embryo or seed coat. The interrelationships between oil content and other seed characteristics were also determined and the significance of these results in relation to plant breeding are discussed.     

Effects of limited enzymatic hydrolysis with trypsin on the functional properties of hemp (Cannabis sativa L.) protein isolate

Effects of limited enzymatic hydrolysis induced by trypsin on the physicochemical and functional properties of hemp (Cannabis sativa L.) protein isolate (HPI) were investigated. The enzymatic hydrolysis was confirmed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC). SEC and differential scanning calorimetry (DSC) analyses confirmed the presence of aggregates in the corresponding hydrolysates (with the degree of hydrolysis of 2.3–6.7%). Functional properties, including protein solubility (PS), thermal properties, emulsifying and foaming properties, and water holding and fat adsorption capacities (WHC and FAC) were evaluated. The PS was remarkably improved by the limited enzymatic hydrolysis at all tested pH values. However, the enzymatic hydrolysis led to the marked decreases in emulsifying activity index, foaming capacity and foam stability, WHC and FAC. These decreases were to a great extent related to the presence of aggregates in the hydrolysates.