Physicochemical Studies of Hard-to-Cook Beans (Phaseolus vulgaris)

Model aqueous systems were used for the study of the cooking quality of beans (Phaseolus vulgaris). These systems were created using graded contents of calcium and magnesium ions, in a ratio of 4:1, to prepare aqueous media with cation content corresponding to 0–400 mg litre^-1 of calcium carbonate. The model systems were used to measure the quality of boiled beans in water of low and high divalent cation content. A boiling time of 60 min was used and the hardness of the boiling beans was measured by an Instron Universal Testing Machine. Cooking of beans in water of low divalent cation content equivalent to 0–50 mg litre^-1 CaCO₃ resulted in well-boiled beans for both types (easy-to-cook and hard-to-cook) of beans. Boiling in water of high divalent cation content led to the formation of very hard beans for both types of bean, while boiling in water of moderate divalent cation content (normal drinking water: 150–250 mg litre^-1 CaCO₃) differentiated between the two categories of beans. These results were further tested by adsorption experiments with divalent cations, on beans boiled (a) in different proportions of boiling water, and (b) in model aqueous systems. The divalent cation content of boiling water and the phytic acid content of the beans proved to be the crucial factors in the hard-to-cook phenomenon of beans. © 1997 SCI.     

INFLUENCE OF VARIOUS SALTS IN THE COOKING WATER ON PECTIN LOSSES AND COOKED TEXTURE OF COWPEAS (VIGNA UNGUICULATA)

The effects of processing with solutions of calcium chloride, magnesium chloride, sodium bicarbonate and a local tenderizer known as ‘Kanwa’ (sodium sesquicarbonate) on pectin losses and cooked texture of cowpea seeds were investigated. For comparison, the cowpeas were processed in double distilled water and a local tap water. Analysis included total pectin, calcium and magnesium content, leached solids, texture and water absorption. The results show that CaCl₂, MgCl₂ and the local tap water increased firmness, Ca and Mg content in the cooked beans compared to distilled water; however, water absorption, leached solids and pectin solubilization were decreased by these salts. Kanwa and NaHCO₃ increased water absorption, leached solids and softness in the cooked beans and also increased pectin solubilization but decreased Ca and Mg when compared to distilled water or the other salts. These changes are discussed with respect to the effects of divalent and monovalent cations on the texture of the bean tissue.     

ABRASION, GRINDING, COOKING and the COMPOSITION and PHYSICAL CHARACTERISTICS of AZUKI KOSHI AN

An, Japanese bean paste, is conventionally prepared by mashing whole cooked beans and removing the seed coats. Sweetened an is prepared by kneading an and sugar. An processed from raw azuki beans pretreated with 1 s of abrasion, 2 s of abrasion, or grinding prior to cooking were compared to an processed from raw whole beans. the effects of increasing the cooking time from 30 to 45 min for beans pretreated with 1 s of abrasion and from 85 to 120 min for whole beans during the an processed the quality of an were also examined. Sweetened an processed from abraded or ground beans was lighter in color than sweetened an processed from whole beans. Increasing the cooking time of abraded beans or whole beans during an processing resulted in dark sweetened an Sweetened an processed from ground beans was harder and more sticky and cohesive than sweetened an processed from whole beans. Sweetened an processed from beans abraded for 1 s was less sticky, but equivalent in cohesiveness to sweetened an processed from whole beans. Sweetened an processed from beans abraded for 2 s was more cohesive than sweetened an processed from whole beans. Sweetened an processed from beans abraded for 1 s or whole beans was hard, sticky, and cohesive when the cooking time during the an processing was increased. Storage and loss moduli of sweetened an , determined by oscillatory shear, decreased with the 2 s of abrasion or grinding pretreatments. Storage and loss moduli of sweetened an processed from beans abraded for I s and whole beans were equivalent. Storage and loss moduli of sweetened an decreased with the increased cooking times. Protein and free lipid contents of an were not affected by the abrasion or grinding pretreatments, or the increased cooking times. Texture attributes of sweetened an illustrated that 1 s of abrasion of raw azuki beans is a more acceptable pretreatment for a quality an process than the 2 s abrasion or grinding pretreatments.     

USE OF THE SHEAR PRESS FOR PROCESS DEVELOPMENT OF SUGAR-COATED BEANS

The main objective of this research was to investigate the possibility of using the shear press to develop an alternative isothermal process equivalent (in hardness) to a commercial process for sugar‐coated beans. Control sugar‐coated cranberry beans were processed according to a typical Japanese dynamic temperature process batch recipe (soak for 12 h at 23C, bring to 98C in 15 min, cook at 98C for 8 min, sugar cook in 50% sugar in water at 70C for 45 min). The treatment samples were processed isothermally (initial soak temperature 77C, then left to soak at 23C for 12 h; cook at 98C for 9, 10, 11, 12, 14 or 16 min; sugar‐cook similar to the control sample) to conform to typical commercial bean‐processing conditions. Bean hardness was measured using a Kramer shear press. On the basis of preliminary results, 11‐min cook time treatment was chosen to determine if discriminatory panels could detect a difference in hardness between the control and treatment. The panelists could not detect a significant difference in hardness between the control and chosen treatment (95% confidence). The shear test may save cost and time for process development of sugar‐coated beans.     

PROCESSING AND FUNCTIONAL PROPERTIES OF YAM BEANS (SPHENOSTYLIS STENOCARPA)

The proximate and selected functional properties of five flours from yam bean (YB) made after the grains were not processed (raw) and processed as boiled, fermented, roasted and malted, were determined. The functional properties were water and fat absorption, gelation, emulsification and whippability. An improvement was observed for protein content of flours processed beans compared to raw flour. Fermentation improved the oil content of the flour. The emulsifying and foaming capacities (50.7 and 40.20%, respectively) observed for raw flour were significantly higher than those for the flours from processed bean. Gelation was significantly (P < 0.05) increased and decreased by fermentation and malting of the bean, respectively. The water absorption capacities ranged from 131.9% in raw flour to 218.8% in flour boiled beans. There were no significant (P > 0.05) differences in the fat absorption capacities of all flours except for the one of fermented beans (0.40 mL/g), which was significantly lower than the value (0.73 mL/g) obtained for the flour from boiled beans. Although a high foaming capacity was observed for raw flour, it was less stable when compared with that of the processed bean flours. Overall, YB flour was found to exhibit good functional properties, and has a great potential for use as an ingredient in selected food systems.     

Chemical and microstructural evaluation of ‘hard‐to‐cook’ phenomenon in legumes (pinto bean and small‐type lentil)

Some physicochemical and microstructural characteristics of hard‐to‐cook (HTC) and easy‐to‐cook (ETC) pinto beans and small‐type lentils were compared. The development of HTC seeds was monitored over 6 months for changes in physicochemical properties. Results indicated that hardness, extent of water absorption and solid loss of HTC legumes were, respectively, 21–97%, 7–72% and 62–236% higher than those of ETC legumes. In addition, darkening of HTC beans and lentils was significantly higher than those of ETC ones. Scanning electron microscope observations indicated deteriorations in cytoplasmic contents of cotyledon cells of hard seeds. Phytic acid and total phenolic contents were, respectively, decreased 36–61% and 43–61% during storage, whereas hardness of seeds was increased 3–6 times. The soaking of hard seeds in sodium solutions resulted in the improvement in legume texture.     

Properties of soya milk and tofu prepared with γ-irradiated soya beans

Soya beans (Glycine max) ‘hwang keum’ were γ-irradiated at dose levels of 0, 2.5, 5, 10 and 20 kGy and the effects of the irradiated soya beans on soya milk and tofu properties were studied. An irradiation dose of 5 kGy caused an increase in yield of soya milk and tofu while having very little effect on their quality. The properties of tofu prepared with the soya beans irradiated at 2.5–5 kGy showed no significant difference from the non-irradiated control. However, at higher doses (10–20 kGy), decreases in yield, water holding capacity and sag value of tofu were observed. Compared with the non-irradiated control, hardness and fracturability in the texture of tofu were both significantly increased when the soya bean had been irradiated at 10–20 kGy, while cohesiveness and adhesiveness decreased. The changes in color values of soya milk and tofu were pronounced at 20 kGy.     

Influence of processing on the content of sugars in green Arabica coffee beans

Quantitative analyses of low molecular sugars in green coffees (Coffea arabica L. var. Acaià) that were processed in parallel either by the traditional wet or the traditional dry method, revealed a close correlation between the kind of post-harvest treatment and the contents of fructose and glucose. While in washed coffee beans (wet processing) only low amounts of these both hexoses were present, those in unwashed coffees (dry processing) were significantly higher. Model-processing experiments in the laboratory confirmed these findings. Moreover, a comparison with the untreated controls revealed that the low levels of both sugars are the consequence of a decrease in the case of wet processing, whereas they remained unchanged or even increased in the case of dry processing. Further minor sugars are also affected by post-harvest treatment. The amounts of galactose, arabinose and mannose show a similar arrangement as those for glucose and fructose, although their overall concentration is about 100-fold lower. Sucrose, the major low molecular sugar in green coffee beans, is not significantly affected by coffee processing. The influence of an active seed metabolism on the observed alterations of the sugar concentrations is discussed.     

Studies on the processing and properties of soymilk. II. Effect of processing conditions on the trypsin inhibitor activity and the digestibility in vitro of proteins in various soymilk preparations

Soymilks prepared from beans which had been soaked either in water or 0.4 M sodium carbonate solution for 24 h as a pretreatment were subjected to heat treatment under different conditions for varying lengths of time, to destroy the trypsin inhibitor activity. The rate of inactivation oftrypsia inhibitor in soy milks prepared from carbonate presoaked beans was faster than that of the water presoaked preparation when processed at 98°C and this effect was primarily associated with the change that occurred in the pH of the former system; The effect of alkaline pH's at 98°C on the inactivation of trypsin inhibitor was examined and it was found that the rate of inactivation was changed from zero order at pff 6.8 to first-order kinetics at pH 9.9. Regression equation relating pH of the system and time of heating at 98°C for 100% destruction of the inhibitor activity is presented. This effect of pretreatment was eliminated when both milks were processed at 115°C in cans because of the constancy of pH under these conditions. The influence of heat processing conditions on the enzymic digestibility of proteins in both soymilks was also studied. The pepsin digestion showed no significant differences between milks prepared from the water and the carbonate presoaked soybeans, and was highest in milks which had not been heat treated. With trypsin the digestibility increased with the degree of heal treatment up to the point where the trypsin inhibitor was destroyed, after which further heating resulted in lower digestibilities. A 19% increase in digestibility by trypsin was observed in the milk prepared from carbonate presoaked beans when compared with that from water presoaked beans and after both milks had been heated at 98°C for just sufficient time to destroy the trypsin inhibitor. When the milk prepared from water presoaked beans was autoclaved at 115°C to the same end point, its digestibility increased but it was still about 6% lower than that of the milk prepared by alkali presoaking method and processed at 98°C. The digestibility of casein using pepsin under the conditions used was lower than that of both soymilks. When trypsin was used the digestibility of casein was approximately the same as that of the adequately processed soymilk from carbonate presoaked soybeans or the autoclavtd soymilk from water presoaked beans. Other effects of using a carbonate presoaking treatment far the production of soymilk have also been discussed.     

Characteristics of winged bean (Psophocarpus tetragonolobus) seeds during soaking and boiling

The effects of soaking small, medium and large seeds of Psophocarpus tetragonolobus (L) DC for up to 24h and then boiling the seeds for up to 30 min, or boiling the raw seeds for up to 120 min, were examined. Trends for hardness and water absorption of the beans were similar for all bean sizes. Soaking and/or boiling reduced the hardness of beans and increased the water absorption leached solids, water holding capacity and swelling power. Small beans were the hardest and showed the lowest level of the other characteristics. Medium sized beans were softer and had higher values of the above four parameters. Soaking for 24 h and then boiling for 30 min was more efficient in reducing the hardness of the beans than boiling for 2h. Linear regression showed high correlations among almost all the parameters measured.     

高温流化改良红小豆蒸煮品质及其机理研究

为解决红小豆质地坚硬、蒸煮品质差、煮饭前需长时间浸泡的问题,采用高温流化技术对红小豆进行蒸煮品质改良,以满足其与白米煮饭时同煮同熟的需要。研究了补水量、流化温度、进料速度对红小豆吸水性能以及蒸煮硬度的影响,然后通过正交实验得到最佳工艺条件为:补水量10∶2、流化温度215℃、进料速度62 kg/h。经最佳工艺条件处理的红小豆吸水指数为194.03%、硬度为1 448.08 g,其蒸煮硬度与白米蒸煮硬度相近,达到了与白米煮饭同煮同熟的要求。通过SEM、XRD、DSC、RVA表征处理前后红小豆微观结构、热力学特性和糊化特性,发现高温流化的红小豆细胞间微孔直径增加、细胞壁破损、淀粉结晶度下降、淀粉热力学特性和糊化行为改变,这些变化可能是高温流化改良红小豆蒸煮品质的内在机理。     

魔芋精粉-氢氧化钙对小米面条品质的影响

研究魔芋精粉和氢氧化钙的联用对小米粉面团的热力学特性以及面条品质的影响。结果表明,添加氢氧化钙对小米粉的热水膨胀度和面条的蒸煮品质具有显著影响,魔芋精粉与氢氧化钙对小米面团的热力学及流变学性质的影响有协同作用。魔芋精粉中的魔芋葡甘聚糖具有强吸水能力,且对蛋白质有促交联作用。添加魔芋精粉可以有效增大小米面团的吸水性,降低小米面团的回生值和面条的硬度,增大面条弹性。添加0.2%氢氧化钙和1.5%魔芋精粉时制得的小米面条的感官品质较好,且微观网状结构均一。魔芋精粉及与氢氧化钙的联用可改善小米食品的加工性能。     

Optimizing Thermal Process for Canned White Beans in Water Cascading Retorts

Based on thermal degradation kinetics and heat transfer expressed as the Ball formula method, a simplified approach was used to optimize sterilization processes for thermal softening of white beans (Phaseolus vulgaris, subsp. nanus Metz., variety Manteca de Leon) Constant retort profiles in a still and end-over-end rotary water cascading retort (Barriquand Steriflow) were used. Quality attributes of beans processed at the optimum were evaluated by a trained taste panel and by a tenderometer. Both approaches could distinguish (P<0.01) between attributes of products from optimal rotary and still processes. End-over-end rotation resulted in faster heat penetration and better quality retention of beans. Texture of white beans processed at 4° or 8°C from the optimal temperature could be distinguished (P<0.01) by the sensory panel and by the tenderometer.     

Osmotic Concentration of Green Beans Prior to Freezing

Osmotic dehydration as an intermediate step in freezing of vegetable tissue was studied. Green beans c.v. Bush Blue Lake-47 were osmotically concentrated in NaCl-water solutions at three concentrations (5, 10, and 17% NaCl by weight) and three temperatures (8, 20, and 40°C). Movement of salt and water was modeled for water loss from and salt uptake by the product. Green beans contacted with 10% NaCl-water solution at 20°C for 30 min were processed further by freezing in an air blast freezer. Evaluation of color, hardness, texture, taste and overall acceptability indicated the product was organoleptically acceptable.     

Effects of micronization pretreatments on the physicochemical properties of navy and black beans (Phaseolus vulgaris L.)

Tempering pretreatments were evaluated for the micronization of navy and black beans. Navy and black beans were tempered to 28 g/100 g and 26 g/100 g moisture, respectively, using water, a mixture of salts of bicarbonate, carbonate and phosphate, a mixture of citric acid and ascorbic acid, or ethylenediaminetetraacetic acid (EDTA) and monitored for texture after cooking, and changes in starch, protein and colour. The mixture of sodium bicarbonate, sodium carbonate and dibasic sodium phosphate was more effective than the mixture of citric and ascorbic acid or disodium EDTA or water alone in reducing the hardness of micronized black beans, while the water and salt mixture were equally effective in reducing the hardness of navy beans and the firmness of both navy and black beans. Lower soluble protein levels and higher levels of gelatinized starch were significantly correlated with a decrease in the hardness of micronized beans. Colour was affected for all micronized black beans, but the colour of micronized navy beans was only affected by the acid treatment. The ability of the bean to imbibe and distribute water in its seed renders seed constituents more sensitive to the effect of heat and solutes, thereby influencing the tempering strategy.     

Microstructures of starch granule,starch digestibilities and predicted glycaemic index of common bean mutants in Taiwan

In this study, the microstructure of starch granule and in vitro starch digestibility were compared in de‐coated seeds of common bean variety Hwachia and its NaN₃‐induced mutants. Significant differences in starch granule size (between 17.92 and 27.00 μm), total starch content (between 436.5 and 456.8 mg per seed) and resistant starch content (between 51.6 and 203.3 mg per seed) were found among mutants. Both boiling and autoclaving decreased resistant starch content in processed common beans. Significant difference in predicted gylcaemic index (pGI) (between 48.82 and 64.55%) for processed beans also existed among mutants. However, 96 h of 4 °C storage increased resistant starch content in processed common beans, possibly resulted from starch retrogradation during storage. Mutants SA‐05, SA‐08 and SA‐31, which have smaller seed weight and lower pGI (average of 50.08%) compared to Hwachia (pGI of 57.05%), can be used to produce common bean based low GI dietary carbohydrate.     

The comparative evaluation of the nutrient composition and sensory attributes of four vegetables cooked by different methods

The following four vegetables; beans (Phaseolus vulgaris var. vulgaris), brinjal (Solanum melongena var. esculentum), knol‐khol (Brassica oleracea var. caulorapa) and radish (Raphanus raphanistrum satvius) were processed either by conventional, pressure or microwave cooking methods and were analysed for their nutritional and sensory profile. Raw samples were used as controls. Microwave cooking resulted in greater moisture loss when compared with vegetables cooked by other methods. The protein, fat, total ash, calcium, phosphorus, iron, and dietary fibre contents of the vegetables did not differ significantly in raw or cooked vegetables. Ascorbic acid was destroyed to the greatest extent by pressure cooking followed by microwave and conventional method. The sensory attributes of cooked vegetables, as evaluated by a paired preference test, revealed that there were no significant differences between cooked radish and knol‐khol but, in the case of beans and brinjal, microwave and conventionally cooked samples were preferred over pressure cooked ones.     

Phytase–phytate–pectin hypothesis and quality of legumes cooked in calcium solutions

Hard‐to‐cook and easy‐to‐cook bean and lentil seeds were boiled in water containing calcium ions at concentrations of 0, 40, 80, 120 and 160 mg L^?1 and their texture and concentration of phytate and various peptic compounds were measured. In order to minimise matrix effects, hard‐to‐cook seeds were prepared from easy‐to‐cook seeds by soaking them at 50 °C. It was found that, as calcium ion concentration increased, phytate concentration decreased and seed hardness increased. Also, during soaking and cooking, phytate and peptic compounds were leached into the water. Losses were larger for hard‐to‐cook seeds than for easy‐to‐cook seeds. These results are consistent with the proposed theory that the formation of hard‐to‐cook legume seeds involves an interaction among divalent cations, phytate and peptic compounds, which is based on the phytase–phytate–pectin hypothesis. Copyright © 2007 Society of Chemical Industry     

Effect of water hardness on cooking characteristics of cowpea (Vigna unguiculata L. Walp) seeds

Cowpeas were cooked in water made hard (or soft) by the separate addition of similar concentrations of certain salts (CaCl₂, MgCl₂, or NaHCO₃). The beans were also cooked in hard tap water and in double distilled water before and after soaking in water. Hard water caused a significant decrease in softness, led to reduced water absorption, and also decreased solids loss in the cooked product, but it increased the cooking time and discolouration of the beans. Hard water also gave rise to a significant ( P <0.05) increase in mineral content, but it had less effect on the proximate composition of the cooked products.     

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