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     

The effect of soaking,germination and cooking on the protein quality of mash beans (Phaseolus mungo)

The protein quality of mash beans (Phaseolus mungo) as affected by soaking, germination and cooking was determined at the 10% dietary protein level using weanling rats. Gains in body weight were 11.5 g for raw beans, 68.5 g for soaked-cooked and 33.0 g for germinated-cooked beans. The protein efficiency ratio values were 0.4, 1.9 and 1.1 for raw beans, soaked-cooked and germinated-cooked beans respectively. Net protein utilisation was improved from 44% for raw beans to 58% after soaking and cooking, but reduced to 47% after germinating and cooking. These changes were entirely accounted for by changes in digestibility, 72, 90 and 81% respectively, and biological values were unchanged at 61, 64 and 59 respectively.     

Oligosaccharides, Antinutritional Factors, and Protein Digestibility of Dry Beans as Affected by Processing

Dry beans (Phaseolus vulgaris) were subjected to soaking, cooking or a combination of both prior to fermentation, and then assessed for oligosaccharides, antinutritional factors and in-vitro protein digestibility. Results showed an important decrease in raffinose oligosaccharides and antinutritional factors. However, an increase of trypsin inhibitor and tannin contents occurred respectively in cooked or soaked-cooked fermented beans and in raw or soaked fermented beans. Appreciable improvement in in-vitro protein digestibility was only observed in cooked or soaked-cooked beans. After fermentation, the largest decreases were observed in soaked-cooked beans (92.75%) for raffinose, in cooked beans (31.57%) for phytic acid, in soaked beans (90.86%) for stachyose, and in raw beans for trypsin inhibitor (38.77%). The highest increase due to fermentation was observed in raw beans for in-vitro protein digestibility (1.73%).     

Effect of various indigenous processing methods on the α‐galactoside and mono‐ and disaccharide content of an Indian tribal pulse,Mucuna pruriens var utilis

The effect of various treatments, such as soaking in different solutions, cooking of raw and soaked seeds, autoclaving of raw and soaked seeds, dehusking of water‐soaked seeds, fermentation of water‐soaked/dehusked seeds, autoclaving of fermented seeds, dry heating of raw seeds and germination, on the levels of mono‐ and disaccharides and α‐galactosides in two varieties of an Indian tribal legume, mucuna bean (Mucuna pruriens var utilis), was investigated. The levels of raffinose, stachyose and verbascose decreased under various treatments. Among the different soaking and cooking/autoclaving treatments, tamarind pulp extract soaking and sodium bicarbonate solution soaking followed by autoclaving procedures were the most effective for removing α‐galactosides (68.4–70.9 and 68.5–68.9% respectively). The lowest reduction of α‐galactosides (8.4–17.2%) was observed in dry‐heated samples. Germination for more than 72 h resulted in the highest reduction of total α‐galactosides (93.6 and 89.6% in white and black varieties respectively). During the germination process, glucose, fructose and sucrose concentrations increased significantly. © 2001 Society of Chemical Industry     

Effect of processing on available carbohydrate content and starch digestibility of kidney beans (Phaseolus vulgaris L.)

The effects of different soaking and cooking methods were investigated on available carbohydrate content and starch digestibility of red and white kidney beans. Total soluble sugars, reducing sugars, non-reducing sugars and starch contents of red and white kidney beans were 9.95 and 11.3%, 0.82 and 0.96%, 9.13 and 10.3%, and 44.4 and 47.8%, respectively. All these available carbohydrate components decreased to various extents as a result of soaking and cooking. From 2.51 to 13.6% and 7.03 to 28.0% of total soluble sugars were lost on soaking kidney beans in tap water and sodium bicarbonate solution, respectively. However, losses in total soluble sugars were maximum (19.9–60.9%) on cooking pre-soaked kidney beans. Losses in starch contents were 4.27 to 24.7% and 30.4 to 70.7% as a result of the soaking and cooking processes, respectively. Besides these losses, starch digestibility of kidney beans was also markedly improved as a result of cooking. However, no appreciable improvement in starch digestibility was observed after soaking kidney beans in water or alkaline solution.     

Effect of processing on ochratoxin A content in dried beans

Dried pink beans naturally contaminated with ochratoxin A (OTA) and dried carioca beans artificially contaminated with OTA by inoculation with Aspergillus ochraceus (ATCC 22947) were tested for ochratoxin A levels as follows: dried beans were washed with water for 2, 60 or 120 min, soaked in water for 60, 120 min or 10 h, and cooked for 60 or 120 min. At each step, test water and beans were separated. Test water, raw beans and cooked beans were analyzed for OTA. The amount of OTA partitioned into water and in residual beans was determined by methanol–sodium bicarbonate extraction, buffer dilution, immunoaffinity column cleanup, liquid chromatographic separation and fluorescence detection. The results demonstrated that the distribution of OTA in processing water and beans depends on the method of preparation. All treatments (washing, soaking and cooking) when applied individually reduced the amounts of OTA retained in bean flour and whole beans. Higher amounts of OTA remained in whole beans than in bean flour after removing the processing water. The combination of the three treatments eliminated about 50% of the toxin from whole beans. This study provides evidence that discarding the washing, soaking and cooking water leads to a significant reduction in OTA contamination in dried beans.     

Water-Holding Capacity in Hard-to-Cook Beans (Phaseolus vulgaris): Effect of pH and Ionic Strength

The effect of pH and ionic strength (IS) of soaking solution on the water holding capacity (WHC) of hard-to-cook (HTC) and control black beans (Phaseolus vulgaris) was evaluated. Beans were soaked 18 hr in solutions covering the pH range 1–7 at constant IS (1.0 M) or in solutions ranging in IS from 0.01 to 1.3M (prepared with either NaCl or CaCl₂) at pH 7. WHC was significantly reduced in the pH range 3.5 to 5.1 in control beans but the effect was not as pronounced with HTC samples which had a lower WHC at each pH. Solutions prepared with NaCl produced significantly lower WHC values than CaCl₂ solutions in the control but not in the HTC beans. WHC values in control beans tended to increase with higher IS, although this effect was not as apparent for HTC beans.     

Effects of Blanching, Soaking, and Cooking on the HCN Yields, Nitrogen, Ash, and Minerals of Lima Beans (Phaseolus lunatus)

Blanching, soaking, and cooking two cultivars of lima bean reduced the HCN concentrations to a safe level. Beans soaked for 12 hr had lower HCN levels than those soaked for 6 hr. Traditional processing was also effective in reducing the HCN concentration in the beans. The treatment of the beans also resulted in a reduction in ash, and the concentration of some minerals.     

Enzymatic changes in pectic polysaccharides related to the beneficial effect of soaking on bean cooking time

BACKGROUND: Cooking time decreases when beans are soaked first. However, the molecular basis of this decrease remains unclear. To determine the mechanisms involved, changes in both pectic polysaccharides and cell wall enzymes were monitored during soaking. Two cultivars and one breeding line were studied. RESULTS: Soaking increased the activity of the cell wall enzymes rhamnogalacturonase, galactanase and polygalacturonase. Their activity in the cell wall was detected as changes in chemical composition of pectic polysaccharides. Rhamnose content decreased but galactose and uronic acid contents increased in the polysaccharides of soaked beans. A decrease in the average molecular weight of the pectin fraction was induced during soaking. The decrease in rhamnose and the polygalacturonase activity were associated (r = 0.933, P = 0.01, and r = 0.725, P = 0.01, respectively) with shorter cooking time after soaking. CONCLUSION: Pectic cell wall enzymes are responsible for the changes in rhamnogalacturonan I and polygalacturonan induced during soaking and constitute the biochemical factors that give bean cell walls new polysaccharide arrangements. Rhamnogalacturonan I is dispersed throughout the entire cell wall and interacts with cellulose and hemicellulose fibres, resulting in a higher rate of pectic polysaccharide thermosolubility and, therefore, a shorter cooking time. Copyright © 2011 Society of Chemical Industry     

Effect of processing on the protein nutritional value of Canavalia gladiata seeds

Evaluation of protein true digestibility (TD), biological value (BV), and net protein utilization (NPU) of diets containing mature sword bean (Canavalia gladiata), seed flour and grits were carried out with male Sprague-Dawley rats. The seed flour and grits were processed by soaking, cooking, soaking and cooking, autoclaving, and roasting. The TD of processed flour (cooked (84.8), soaked and cooked (76.2), autoclaved (82.0), roasted grits (64.5), and roasted flour (61.2)) were significantly higher (p < 0.05) than in the raw (51.4) and the soaked only grits (35.8). Soaking the grits decreased the TD. The BV of cooked grits and grits cooked after soaking were significantly higher than that of the other processed samples (p < 0.05). However, the BV of the diets containing cooked and soaked and cooked grits were not significantly different. The NPU of the cooked grits (39.4) and grits cooked after soaking (37.6) were significantly higher (p < 0.05) than that of the other processed samples (autoclaved grits (31.0), roasted grits (19.5), roasted flour (10.8), and soaked only grits (1.6)). The NPU of all the processed samples were significantly lower than the reference casein (p < 0.05). The highest protein nutritional quality was obtained by either cooking the grits or by soaking and cooking the grits. In vitro protein digestibility measurements were not well correlated to the true digestibility.     

IMPROVING ENZYMATIC REDUCTION of MYO-INOSITOL PHOSPHATES WITH INHIBITORY EFFECTS ON MINERAL ABSORPTION IN BLACK BEANS (PHASEOLUS VULGARIS VAR. PRETO)

Activation of endogenous or addition of exogenous phytases during food processing gives a chance to reduce the phytate content in the final product to a nutritionally acceptable level. Optimal conditions for the endogenous phytases of black beans, this is 60C and pH 6.0, resulted in a 55% reduction in 1P₆ after soaking and cooking. the sum of 1P5 and 1P₅ was reduced by 54%. 1P₆ reduction was most extensive when black beans were soaked at 50C while adding exogenous phytases during the last 2 h of soaking. After soaking and cooking 1P₆ was degraded by 85% and the sum of 1P6 and 1P5 was reduced by 82 % compared to the values in raw beans when adding Escherichia coli phytase. Using rye phytase the values were estimated to be 73% and 70%, thereby a clear accumulation of IP₄ occurred. Thus, a significant improvement in reduction of mnyo-inositol phosphates with adverse effects on mineral bioavailability has been achieved in comparison to the usual household procedure.     

Effect of food intake on protein quality measured in chicks by traditional or biochemical methods

Previous studies have shown that the activities of the hepatic enzymes xanthine dehydrogenase and nucleoside phosphorylase, as well as the uric acid excreted, can be used to determine the quality of the protein consumed in chickens, in a short time and using a small amount of the test protein. A common observation in protein quality evaluation is that the food intake of the control animals is considerably greater than that observed in those receiving proteins of low quality. Since this can affect the results, this study measured the quality of garbanzo bean and black bean proteins in chickens fed these beans ad libitum, feeding the bean diets at the level observed in the controls (soy protein+methionine) by enteral intubation or pair feeding the controls with the amount of food consumed by the chickens receiving the bean diets. In every case, protein quality was determined by protein efficiency ratio, net protein utilisation or the biochemical methods used in this study. The results showed that, when fed ad libitum, the animals assigned to the bean diets exhibited a lower food intake than the controls but, by tube feeding, food intake was made equal in both groups. Equal consumption, between these groups, was also obtained by reducing the amount of food offered to the controls to the levels measured in the groups assigned to the bean diets (pair feeding). These feeding strategies had a marked effect on growth, carcass protein content, protein catabolism and also in the results of protein quality. Thus, the control whose intake was reduced grew less, accumulated less protein in tissues and catabolised more of the protein consumed than the control fed ad libitum. In contrast, the chickens assigned to the bean diets, but whose food intake was increased by tube feeding, grew better, accumulated more protein in tissues and catabolised less protein. In general, the results of these experiments confirm the effectiveness of the biochemical methods for estimating protein quality and indicate that the protein quality of both garbanzo beans and black beans increased when it was measured at a food intake equivalent to that measured in the control animals. Since the overall purpose of this study was to evaluate techniques for protein quality determination meant to be applicable to humans nutrition rather than poultry nutrition, single proteins were used instead of combinations of proteins. © 1998 Society of Chemical Industry.     

Influence of Pre-Soaking on Black Bean Cooking Kinetics

Soaking of black beans (Phaseolus vulgaris L.) and the subsequent effect on cooking kinetics was investigated. Unsoaked beans and beans soaked in water or a salt combination solution were water cooked at temperatures of 90–135°C. Bean softening did not follow first order kinetics. Using D_T values (defined as cooking times necessary to reach an “eating-soft” texture: Instron puncture force of 150g), softening activation energies (Ea's) for unsoaked, water, and salt combination soaked were 19.1, 31.3, and 38.9 Kcal/mole, respectively. Z values were calculated as 17, 22 and 36C°, respectively. These relationships suggest ways of safely reducing cooking time and energy expenditures.     

Rapid Rehydration Methods for Dried Beans

Rapid methods of rehydrating dried kidney, pinto or navy beans by soaking at 82°C or 93°C for 5, 10 or 30 min were compared to standard 18 hr soaking at ambient temperature. Canned beans processed 21 min at 121°C had higher drained weights and softer texture with fewer split beans than those processed 41 min at 116°C. Kidney, pinto and navy beans soaked 30 min at 82°C had higher drained weight than those soaked 30 min at 93°C. Hydration coefficient (2.07) of controls (18-hr soak) and beans soaked 82°C (1.94) or 93°C for 30 min were not different. Pre soaking 30 min at 82°C provided adequate rehydration prior to canning.     

The effect of gestation and of protein quality on the nutritive utilization of protein

A study was made of the effect of protein quality on gestation and on digestive and metabolic utilization in Wistar rats. The protein level of the diet was 14%, and the protein sources used were: casein, beans and a mix of beans and wheat, in order to complement the essential amino-acids deficient in both protein sources. Gestation increased food intake in the 3 groups of experiments, in which distinct protein sources were used. Protein quality did not affect food intake in the two physiological situations under study (gestation and non-gestation). In pregnant animals, the greatest weight gains were obtained with the casein diet, while in non-pregnant ones the weight increases were greater with the diet of beans and wheat. The smallest gains recorded were those of pregnant and non-pregnant rats fed a diet of beans. Gestation did not affect protein-absorption. The digestive utilization of protein was superior with the casein diet. The study of nitrogen retention showed: 1. The pregnant animals retained more nitrogen than the non-pregnant animals with all of the diets under study. 2. In pregnant animals, the greatest metabolic utilization took place with the casein diet, with little difference between the bean and bean-wheat mix diets, although in the latter it was slightly superior.     

Oligosaccharides in raw and processed legumes

 Oligosaccharides from several types of raw and processed legume seeds consumed in Spain, e.g. lentils (Lens culinaris L.), chickpeas (Cicer arietinum L.), red kidney beans (Phaseolus vulgaris L.), white common beans (Phaseolus vulgaris L.), “Judiones de la Granja” great white beans (Phaseolus vulgaris L.) and faba beans (Vicia faba L.), were analysed by high performance liquid chromatography. The total sugar content ranged from 6.69% to 9.99%, and oligosaccharides represented 25–46% of the total sugar, in the various dry legumes. The main oligosaccharide in raw faba beans was verbascose (3.32%), and stachyose in the remaining legumes (2.21–3.23%). Different amounts of sucrose and traces of glucose, fructose and small amounts of inulin were present in raw samples of all the legumes. After soaking in tap water the loss of oligosaccharides was lowest in red beans (1.25%) and highest in common white beans (27.6%). Pressure cooking, without previous soaking, resulted in no oligosaccharide loss in common white beans but a loss of up to 32% in chickpeas. After pressure cooking of soaked legumes, the loss of stachyose ranged from 14.2% in red beans up to 35.9% for lentils. Substantial amounts of flatus-producing factors can be eliminated by common processing methods. Received: 12 May 1997 / Revised version: 17 July 1997     

Oligosaccharides in raw and processed legumes

 Oligosaccharides from several types of raw and processed legume seeds consumed in Spain, e.g. lentils (Lens culinaris L.), chickpeas (Cicer arietinum L.), red kidney beans (Phaseolus vulgaris L.), white common beans (Phaseolus vulgaris L.), “Judiones de la Granja” great white beans (Phaseolus vulgaris L.) and faba beans (Vicia faba L.), were analysed by high performance liquid chromatography. The total sugar content ranged from 6.69% to 9.99%, and oligosaccharides represented 25–46% of the total sugar, in the various dry legumes. The main oligosaccharide in raw faba beans was verbascose (3.32%), and stachyose in the remaining legumes (2.21–3.23%). Different amounts of sucrose and traces of glucose, fructose and small amounts of inulin were present in raw samples of all the legumes. After soaking in tap water the loss of oligosaccharides was lowest in red beans (1.25%) and highest in common white beans (27.6%). Pressure cooking, without previous soaking, resulted in no oligosaccharide loss in common white beans but a loss of up to 32% in chickpeas. After pressure cooking of soaked legumes, the loss of stachyose ranged from 14.2% in red beans up to 35.9% for lentils. Substantial amounts of flatus-producing factors can be eliminated by common processing methods. Received: 12 May 1997 / Revised version: 17 July 1997     

Dietary fibre content of dry and processed beans

Common beans (Phaseolus vulgaris L.) are a good source of protein, vitamins, minerals and especially dietary fibre. As beans are never eaten raw, the effects of soaking, cooking, soaking–cooking and canning on soluble, insoluble and total dietary fibre contents of beans are studied. Total dietary fibre content was determined by enzyme-gravimetric method. The fraction of insoluble dietary fibre was corrected for the content of resistant starch, determined as part of the total starch in insoluble fibre. The results indicate that thermal processing decreased the insoluble fibre content, and consequently the total dietary fibre content of beans. Soaking and cooking of beans significantly (P⩽0.05) increased the resistant starch content. The data on dietary fibre content of processed food are much more relevant than those of raw food. Thus food composition tables should contain as much data on processed food as possible.     

Emulsifying Properties of Ethanol Soaked Soybean Flour

Soy flours prepared from soybeans soaked at 60°C for 6 hr in distilled water, 15% ethanol, or 0.1M NaHCO₃ in 15% ethanol were tested for their emulsifying capacity (EC) at pH 4.5, 6.5, and 9.0. At pH 4.5 and 6.5, there were no significant differences in EC among treatments; at pH 9.0, the EC was highest for soy flour from beans soaked in water, intermediate for flour from beans soaked in 15% ethanol, and lowest for flour from beans soaked in 0.1 M NaHCO₃ in 15% ethanol. The relationship between the amount of soluble protein and EC was inverse with EC decreasing sharply up to about 60 mg soluble protein/50 mL of flour dispersion. Photomicrographs of air incorporation during emulsion formation are presented.     

Mechanistic insight into common bean pectic polysaccharide changes during storage,soaking and thermal treatment in relation to the hard-to-cook defect

Different mechanisms responsible for the development of the hard-to-cook defect in common beans during storage, their soaking behavior and softening during thermal treatment have been previously suggested. However, these mechanisms have not been sufficiently confirmed by direct molecular evidence. This research aimed at gaining a detailed mechanistic insight into changes occurring in Canadian wonder bean pectic polysaccharides during storage, soaking and/or thermal treatment in different brine solutions in relation to the development and manifestation of the hard-to-cook (HTC) defect. Both fresh or easy-to-cook (ETC) and stored (HTC) bean samples were either soaked or soaked and thermally treated in demineralized water, solutions of Na₂CO₃ and CaCl₂ salts followed by extraction of cell wall materials. Pectic polysaccharide properties examined included sugar composition, degree of methylesterification (DM), extractability and molar mass (MM). The DM of pectin from ETC and HTC beans was similar but low (< 50%). Upon (pre)treatment in a Na₂CO₃ solution, solubilization of pectic polysaccharides, especially the strongly bound chelator- (CEP) and Na₂CO₃- (NEP) extractable pectins was enhanced leading to increased amounts of water extractable pectin (WEP). Also, there was a decrease in high MM polymers paralleled by an increase in β-elimination degradation products. These observations are in line with the fast cooking behavior of beans (pre)treated in a Na₂CO₃ solution. In contrast, (pre)treatment in a CaCl₂ solution hindered softening leading to the failure of the beans to cook. The beans (pre)treated in a CaCl₂ solution showed increased high MM polymers and lack of cell wall separation. Therefore, it can be inferred that development of the hard-to-cook defect in Canadian wonder beans during storage and its manifestation during soaking and subsequent thermal treatment is largely reflected by the pectic polysaccharide properties in line with the pectin hypothesis. Our data suggest the release of Ca⁺⁺ leading to pectin cross-linking and the increase or decrease of β-elimination depolymerization. However, the relatively high amounts of neutral sugars and strongly bound NEP in HTC seeds do not allow to rule out the possible existence of non-Ca⁺⁺ based pectin cross-linking.