PECTIC SUBSTANCES OF FABA BEANS AND THEIR RELATION TO TEXTURE OF COOKED BEANS

Twenty samples of faba beans which showed wide variations in texture after cooking were analyzed for total pectin and pectin fractions (i.e., H2O-, EDTA-, and NaOH-soluble fractions) contents of decoated seeds and seed coats. Total pectin ranged between 0.9 and 1.6% of the cotyledons and between 0.5 to 1.0% of the seed coats. Water-soluble pectin was the highest fraction with a mean value about 50% and 40% of the total pectin for the decoated seeds and the seed coats, respectively. No consistent significant correlation was found between the pectic substances fractions and the texture of cooked faba beans for both 1980 and 1981 samples except for the water-soluble pectin as a percentage of the total pectin content of decoated seeds (r = 0.77, P< 0.01 for penetrometer and r =−0.76, P<0.01 for Kramer maximum shear force for 1980 and 1981, respectively).     

The effect of pod and seed positions on the physical and cooking properties of faba beans (Vicia faba)

The effect of pod location on plant (lower, middle and upper regions) and seed position inside the pods (nodular, middle and terminal) on certain characteristics of dry and stewed faba beans were studied. The weight, volume, relative density, seed coat (%), hydration and swelling coefficients were determined for dry seeds. Hydration and swelling coefficients, fractured beans (%), penetrometer readings and scores of colour, granulation and softness (by taste panel) were evaluated for stewed beans. The weight, volume, relative density, pH, and total and soluble solids content of the stewed liquor were also measured. Analysis of variance showed that the weight and volume of 1000 dry seeds were significantly (P<0.001) affected by pod location and seed position. Higher values were obtained for lower pods and terminal and middle seeds. Seeds from upper pods had the highest percentage of seed coat. Pod location showed a significant effect on the weight, volume, pH, soluble and insoluble solids of stewed liquor. No significant effect was found for pod location or seed positions on the characteristics of stewed beans, except the hydration coefficient which was significantly affected by pod location.     

Relationship Between Cookability and Some Chemical and Physical Properties of Faba Beans (Vicia faba L.)

Cookability index (determined by penetrometer) and some physical properties were determined for 20 samples of faba beans (Vicia faba L.) grown in Canada and Egypt. Proximate composition was determined for eight samples. Starch of four bean samples, representing extremes in cookability, was examined by differential scanning calorimetry (DSC) and amylography. Statistical analyses showed highly significant correlations between cookability index and hydration coefficient and percentage seed coat for the Egyptian samples (high seed coat content). For the Canadian samples (low seed coat content), highly significant correlations were obtained between cookability index and thousand seed weight, peak amylograph viscosity and falling number values of cotyledon flour. Differences between soft and hard cooking samples were observed by DSC and amylography of the starch. The study showed that the hard to cook phenomenon in faba beans is controlled by characteristics of both seed coat and cotyledons and is not a “hard shell” problem only.     

Rohament P as a processing aid in Medammis preparation

Two lots of dry faba bean (Viciufubu L.) seeds of different cookabilities were used to prepare Medammis which is considered as a staple food for the majority of the population in Egypt. Seeds were soaked with shaking in a citrate buffer of pH 4.5 containing 0.1 % Rohament P enzyme at 45°C for 12 h. After draining and washing, beans were mixed with distilled water at 1:4 ratio (w/v) and autoclaved at 115°C for 2 h. No obvious differences were observed for the hydration coefficients of beans soaked in presence and/or absence of enzyme. In contrast, cooked beans exhibited appreciable textural differences as assessed objectively for the control and treated samples. Moreover, hard-to-cook beans were softened to the acceptable texture as the five fold of enzyme concentration was applied. Data of quantitative and TLC methods clearly indicated leaching out of sugars as a result of maceration action of middle lamella by means of Rohament P.     

SEED COAT EFFECTS IN COOKED RECONSTITUTED BEAN TEXTURE

The contribution of seed coat to cooked reconstituted bean texture was assessed by measuring sensory and instrumental parameters of beans with and without coats and also seed coats alone. Experiments using white beans stored for one year under tropical conditions to induce the hard-to-cook (HTC) defect or temperate conditions both resulted in reductions in the order of 50% in puncture force and sensory properties of beans when the seed coat had been removed. HTC bean texture was influenced less by absence of the seed coat than texture of soft beans. Seed coats softened during cooking but those from HTC beans softened less than those from soft beans. It is possible that seed coats harden during tropical storage by a lignification-type mechanism. Beans with harder seed coats absorbed less water during soaking which may contribute further to bean hardness.     

pH, TEMPERATURE AND HYDRATION KINETICS OF FABA BEANS (VICIA FABA L.)

Soaking kinetics of dry faba beans was studied in the temperature range 20–65C, and at pH 3, 6, 9 and 12 by the method of weight gain until equilibrium conditions were attained. Increasing the soaking temperature from 20 to 35C resulted in a small increase in hydration rate constants as compared to that realized with further increase to 50 and 65C in the investigated range of pH. Soaking at 65C decreased the amount of water absorbed by the beans and the time at which equilibrium was attained. Beans soaked at alkaline pH exhibited higher hydration rates especially when hydration was carried out at ≥ 50C     

Protein and starch content of raw,soaked and cooked beans (Phaseolus vulgaris L.)

Organoleptic qualities are an important factor in the market value of legumes, especially in developed countries. Unfortunately, the molecules that have the greatest influence on the texture of beans undergo important transformations during soaking and cooking. Moreover, the extent to which these changes are linear is unknown, making uncertain the use of raw beans in chemical screenings for sensory properties. Results of our experiments show that the amount of protein and amylose present in raw beans provides a good indicator of these substances in cooked beans (correlation coefficients between raw and cooked beans = 0.91, p ? 0.001 and 0.87, p ? 0.01, respectively). The Mg content in the raw seed coat also shows a strong correlation with that found in the cooked seed coat (r = 0.86, p ? 0.01). The correlations found for the other traits are weaker, indicating that the evaluation of raw samples is not predictive of the findings in cooked beans.     

The Effects of Fungal Infection on the Chemical and Functional Properties of Chickpeas(Cicer arietinum)and Faba Beans (Vicia faba)

We investigated the effects of fungal infection on the chemical composition and functional properties of ‘healthy’ and ‘diseased’ chickpeas and faba beans which were classified on the basis of visual contamination. Following fungal testing, the ‘diseased’ seeds were shown to possess relatively low levels of potentially toxigenic fungi as a proportion of the total number of colonies, which was also lower than expected. Mycotoxins could not be detected in either crop. There were no appreciable differences in the average moisture, ash, crude fat, crude protein and acid detergent fibre contents between the ‘healthy’ and ‘diseased’ grain of both chickpeas and faba beans. Hydration capacity of the whole seeds did not differ between ‘healthy’ and ‘diseased’ grain samples of both chickpeas and faba beans. However, hard seed coatedness was greater in both ‘diseased’ chickpeas and faba beans compared with the ‘healthy’ samples. Water and oil absorption capacities were affected by disease in the chickpea and faba bean flours, although the effects were inconsistent between the two seed types. The foaming characteristics of the ‘diseased’ chickpea and faba bean flours were severely affected.     

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     

THE EFFECT OF PHYTATE AND FIBER CONTENT ON COOKING QUALITY IN FABA BEANS

Seventy-six faba bean lines were analyzed for their phytic acid content in the whole seeds and in the cotyledons. The fiber content was also determined in 17 Faba bean lines. The seed weights; % testa weight-of the seeds; and % moisture uptake (water imbibition) after overnight soaking in distilled water or increasing concentrations of EDTA solutions were measured and recorded. The relation between the above mentioned dependent variables and the cooking time for seed softening (min.) in 76 faba bean lines was studied and simple and multiple correlation coefficients were computed with a total of 70 operations. Significant correlation coefficients were found between phytic acid content in the cotyledons, % testae weight of the seeds; moisture uptake after soaking the seeds in distilled water overnight and cooking time for 50% softening (min). The faba bean lines 606/ 303; 606/ 308, 608/ 334, 609/ 350, proved to be of excellent cooking quality, since their cooking time for 50% seed softening did not exceed 10 min.     

Relating consumer preferences to sensory and physicochemical properties of dry beans (Phaseolus vulgaris)

BACKGROUND: Dry beans (Phaseolus vulgaris) have a range of varieties, colours and sizes. Differences in physicochemical and sensory properties influence consumer choices for beans. This study related consumer preferences to sensory and physico‐chemical properties of selected bean varieties—Jenny, Kranskop, PAN 148, AC Calmont, PAN 150 and Mkuzi—grown in Mpumalanga (MP) and Free State (FS) in South Africa. RESULTS: Significant (P < 0.05) variety, location as well as location × variety interaction effects were found for both physico‐chemical and sensory properties of beans. Jenny‐FS, Mkuzi and PAN 148‐MP beans had relatively long cooking times (>60 min). Some beans (e.g. PAN 150 and Mkuzi beans) were described as bitter, soapy and metallic with a raw‐bean flavour whereas more preferred beans (e.g. Jenny‐MP, Kranskop‐MP) were sweet, soft and with a cooked‐bean flavour. CONCLUSION Apart from small seed size, sensory characteristics such as bitter taste, soapy and metallic mouthfeel and hard texture contributed to consumers' dislike of certain bean varieties. The sweet taste, cooked‐bean flavours, soft and mushy textures of the most accepted varieties seemed to be related to beans with good hydration capacities that facilitated softening during cooking. Copyright © 2007 Society of Chemical Industry     

Effect of Storage on the Biochemical Structure and Processing Quality of Adzuki Bean (Vigna angularis)

Storage of adzuki beans and other pulse grains causes biochemical and physical changes that affect the hydration properties of the beans. This affects the quality of products made from the beans such as the Japanese bean paste “ann.” Storage, particularly under unfavourable conditions, leads to the “hard shell” phenomenon, where beans fail to imbibe water when soaked and remain hard, and the “hard-to-cook” phenomenon where the seeds hydrate normally, but the cotyledon fails to hydrate and soften during cooking. The hard shell phenomenon is attributable to impermeability of the seed coat to water, which is due to biochemical changes in the seed coat, such as the formation of protein-tannin complexes, and biophysical changes such as reduction in size or closure of the straphiole aperture in the hilum area—the main area for water entry into the adzuki bean. The hard-to-cook phenomenon is due to changes in the cotyledon tissue, which include formation of insoluble pectinates, lignification of the cell wall and middle lamella, interaction of condensed tannins with proteins and starch, and changes to the structure and functionality of the cellular proteins and starch.     

High apparent ileal digestibility of amino acids in raw and germinated faba bean (Vicia faba)‐ and chickpea (Cicer arietinum)‐based diets for rats

The effects of germinated faba bean (Vicia faba minor var Alameda)‐ and chickpea (Cicer arietinum kabuli var Athenas)‐based diets on performance, N utilisation, amino acid ileal digestibility and plasma concentrations were studied in growing male Wistar rats. Raw and germinated faba bean and chickpea seed meals were incorporated in essential amino acid‐supplemented and energy‐equalised diets as the only sources of protein. A lactalbumin‐based diet equalised in protein (100 g kg^?1) and digestible energy (15.5 kJ g^?1) with the test diets was used as control. Weight gains, gain/feed ratios, N retention and NPU values of animals fed raw or germinated legumes were lower than those of rats given the control (lactalbumin) diet, while faecal dry weights were higher. However, N retention and NPU values of rats fed germinated faba bean diets were higher and faecal dry weights lower than those of animals fed non‐germinated faba bean diets. Liver and thymus fresh and dry relative weights were lower than controls for all legume diets, whilst small intestine, caecum and colon relative weights were higher than controls for non‐germinated faba beans and chickpeas either germinated or not. Caecum and colon fresh and dry relative weights of rats fed germinated faba bean seeds were lower than those of rats fed non‐germinated faba beans and not different from controls. Except for aspartic acid and proline in rats fed raw faba bean diets, apparent ileal digestibilities of amino acids were not different or higher in rats fed legume diets as compared with controls. Except for arginine, apparent ileal amino acid digestibility was higher for germinated than for non‐germinated faba bean seeds. The amounts of glycine, arginine and ornithine in plasma significantly increased whilst those of threonine, alanine, leucine and lysine decreased with respect to controls in faba bean‐ or chickpea‐fed rats, either germinated or not. We conclude that (a) germination of faba bean seeds gave rise to a significant (P < 0.01) but limited improvement in performance, N retention and apparent ileal digestibilities of some amino acids in growing rats compared with non‐germinated seeds, while there was no detectable effect in the case of germinated chickpea seeds, and (b) the apparent ileal amino acid digestibility of essential amino acid‐supplemented diets based on faba bean or chickpea meals, either germinated or not, is similar or even higher than controls. © 2002 Society of Chemical Industry     

Hydrothermal treatments of two cowpea (Vigna unguiculata L. Walp) varieties: effect of micronisation on physicochemical and structural characteristics

The effects of a hydrothermal treatment consisting of tempering (to 41% moisture) and heating to 153 °C (micronisation) on the structural and physicochemical characteristics of two cowpea varieties were studied. The untreated varieties had similar cooking times, although cooked Bechuana white cowpeas were significantly (P ≤ 0.05) softer and had a higher incidence of splitting than Var. 462 cowpeas. This may be due in part to differences in cotyledon structure affecting water uptake during cooking. The hydrothermal treatment changed the physical structure and chemical properties of the cowpea seeds. This led to significant (P ≤ 0.05) reductions in the cooking time of micronised Bechuana white and Var. 462 cowpeas, by 47 and 36% respectively, as compared with control samples. Micronisation caused physical fissuring of the seed coat and cotyledon and significantly (P ≤ 0.05) reduced the bulk density of treated seeds. These changes in the physical structure significantly (P ≤ 0.05) improved the initial water uptake during soaking and cooking, increased the enzyme‐susceptible starch and reduced the protein solubility and hydration capacity of the cowpea seeds. Cooked (60 min) micronised cowpeas also had significantly (P ≤ 0.05) more splits and a significantly (P ≤ 0.05) softer texture than control samples. Copyright © 2005 Society of Chemical Industry     

Effect of seed coat thickness and blanching on the water absorption by soybeans

Water absorption by whole soybeans and by soybeans with their seed coat partially abraded was compared. The rate of absorption by the whole seeds was less than that for the abraded seeds. The effect of blanching on the rate of water absorption and absorption capacity in whole soybeans and in beans with their moisture content adjusted by storage to 33 and 65% ERH was examined. Blanching the seeds resulted in an increase in the rate of absorption but reduced the absorption capacity of the beans. The samples with the higher water activity showed the largest increase.     

Nutritional value of broad bean seeds. Part 1: Starch and fibre

This paper characterizes starch and dietary fibre in the seeds of fine-size and large-size seed varieties of broad bean and in edible varieties of pea for comparison. The experimental material included seeds at full physiological maturity. The fine-size seed varieties of broad bean, Gobik and Goral, contained slightly less total starch (62.32% and 62.19% of dry matter) than the large-size seed varieties, Windsor Bialy and Bartom (65.32% and 65.26% of dry matter). It was shown that fine-size seed varieties of broad bean are a good source of resistant starch, which is comparable to large-size seed varieties. As far as the content of total starch is concerned, the share of this form of starch in broad bean seeds amounted to 1/3. Digestible starch in broad beans was in the range of 39-42% of dry matter, pea contained approximately one half less starch of this type. Moreover, it was found that the relation of rapidly digestible starch to slowly digestible starch amounted to 1:1 irrespective of broad bean variety. Dietary fibre in broad beans was in the range of 20.36%-26.79% of dry matter while half of it was found to be concentrated in the seed coat. The soluble fraction of the total content of fibre amounted to 11.81% in the Bartom variety and up to 15.89% in the Gobik variety.     

Comparison of Antimutagenic Activity of Phenolic Compounds in Newly Harvested and Stored Common Beans Phaseolus vulgaris against Aflatoxin B1

ABSTRACT: Phenolic compounds were extracted from recently harvested or stored black Jamapa beans ( Phaseolus vulgaris ) that were subjected or not to thermal treatment. The beans studied were cropped in the same area and were from the same lot. The highest amount of condensed tannins (CT) was found in the seed coat of recently harvested beans [222.41 ± 16mg of (+)-catechin equivalents per gram of seed coat]. After 2 yof storage, the amount of CT dropped significantly [35.8 ± 3.4 mg of (+) -catechin equivalents per gram of seed coat]. Thermal treatment significantly reduced the amount of CT in whole beans by approximately 70%. The raw seeds contained 13.76 ±1.2 mg of (+)-cat-echin equivalents per gram of seeds and a portion of CT appeared in the broth [9.4 ± 0.1 mg of (+) -catechin equivalents per gram of lyophilized broth]. The antimutagenic activity of these extracted phenolic compounds was tested against aflatoxin B₁ (AFB₁) in the Kado microsuspension assay. Newly harvested beans showed higher antimutagenic activity against AFB₁ mutagenicity than stored beans. The results suggest that to take the maximum advantage of components with biological activity present in beans, they must be used fresh.     

Distribution and degradation of tetrachlorvinphos on stored faba beans and soya beans

The distribution and degradation of [CH₃-¹⁴C]tetrachlorvinphos in stored fabe beans and soya beans were studied for 30 weeks at moisture contents and temperatures similar to those prevailing under normal storage conditions. Tetrachlorvinphos penetrated the seed coat and the insecticide residues inside the beans increased with storage time. A considerable portion of radioactivity, amounting to about 20–30% of the applied dose in faba beans and 30–40% in soya beans, was present in a non-extractable form. Residues on the seed coat consisted mainly of unchanged insecticide. The internal extract contained both unchanged insecticide and desmethyltetrachlorvinphos which was present in a free and a conjugated form. Dimethyl phosphate and monomethyl phosphate were identified as hydrophilic ¹⁴C-degradation products. The degradation of tetrachlorvinphos proceeded mainly via cleavage of methoxy groups. The nature and percentage of metabolites varied slightly with storage period. A scheme for possible degradation routes of tetrachlorvinphos on stored beans is suggested.     

Evolution of soluble carbohydrates during the development of pea, faba bean and lupin seeds

Seeds of pea (Pisum sativum L. cv. Ergo), faba bean (Vicia faba ssp. minor Harz., cv. Tibo) and yellow pea lupin (Lupinus luteus L. cv. Juno) were sampled at different days after flowering (DAF) and their content of soluble carbohydrates was determined: Analysis of samples showed thatmyo-inositol, fructose, glucose, galactose and sucrose were found in high abundance early in development and their content decreased gradually during maturation. -Galactosides, which includes the content of raffinose, stachyose and verbascose, started to appear later in seed development, at 37 DAF in peas, 40 DAF in faba beans and 45 DAF in lupins. Their accumulation increased considerably during seed growth, and the maximum content was obtained in mature seeds; 3.8% in peas, 4.5% in faba beans and 10.4% in lupins. Results obtained for these sugars during seed development were fitted to modelling curves in order to predict sugar content at different development stages.     

Seed coat mucilages: Structural,functional/bioactive properties,and genetic information

Seed coat mucilages are mainly polysaccharides covering the outer layer of the seeds to facilitate seed hydration and germination, thereby improving seedling emergence and reducing seedling mortality. Four types of polysaccharides are found in mucilages including xylan, pectin, glucomannan, and cellulose. Recently, mucilages from flaxseed, yellow mustard seed, chia seed, and so on, have been used extensively in the areas of food, pharmaceutical, and cosmetics contributing to stability, texture, and appearance. This review, for the first time, addresses the similarities and differences in physicochemical properties, molecular structure, and functional/bioactive properties of mucilages among different sources; highlights their structure and function relationships; and systematically summarizes the related genetic information, aiming with the intent to explore the potential functions thereby extending their future industrial applications.