Hydration Kinetics of Red Kidney Beans (Phaseolus vulgaris L.)

Soaking of dry red kidney beans was studied at 20, 30 40 and 60°C by the method of weight gain until equilibrium conditions were attained. Water absorbed during soaking was a function of both soaking time and temperature. Soaking at high temperatures increased the hydration rate constant and decreased soaking time to achieve equilibrium. Compared to unblanched beans, the application of a pre-blanching step considerably reduced hydration times of blanched beans. Due to the plasticity effect acquired upon blanching, blanched beans showed a significantly high hydration rate constant and exhibited a more constant equilibrium moisture content regardless of soaking temperature. Activation energy values (E_a) of the hydration process were 6.48 Kcal/mole for blanched and 14.25 for unblanched beans.     

Interpretation of the force deformation curves of soaked red kidney beans (Phaseolus vulgaris L.)

In this study, the textural patterns of red kidney beans soaked in water at 20, 30, 40 and 60 °C are reported. Texture (hardness) was measured instrumentally by cutting with a wedge-type blade mounted on an Instron Universal Testing Machine at a speed of 200 mm min⁻¹. The general trend of the force deformation curves was similar for all of the soaking temperatures studied throughout the soaking process. At initial stages of hydration, textural changes were a function of the soaking time. However, once the hydration process attained equilibrium, changes in texture became minimal and were within the range of 34 ± 2 N, regardless of the soaking temperature and hydration time. The force deformation curves were influenced by the presence of a large cavity between the two cotyledons of red kidney beans. Interpreting textural patterns of soaked beans would provide a better control of the water absorption process, which subsequently influences changes in texture.     

Effect of Storage Time and Conditions on the Hardness and Cooking Quality of Adzuki (Vigna angularis)

A storage trial of two varieties of adzuki (Vigna angularis), Bloodwood and Erimo, produced in Australia, was conducted to determine the effect of various combinations of temperature, humidity and length of storage on bean quality. The beans were stored for up to 6 mo under the following conditions: temperature (10, 20 and 30 °C), relative humidity (RH) (40 and 65%). Storage of adzuki at elevated temperature (30 °C) and low relative humidity (40%) resulted in the greatest loss of bean moisture, increase in hydration times and decrease in bean cooking quality, i.e. increased hardness of cooked beans. The best storage conditions for the preservation of adzuki quality were 10 °C and 65% RH.     

Phytate Reduction in Brown Beans (Phaseolus vulgaris L.)

Brown beans (Phaseolus vulgaris L.) were subjected to treatments to evaluate effects of pH, temperature, CaCl₂, tannase and fermentation on degradation of phytate. Soaking was performed at 21°C, 37°C and 55°C at pH 4.0, 6.0, 6.4, 7.0, and 8.0. Optimal conditions for phytate degradation were pH 7.0 and 55°C. After soaking 4, 8 or 17 hr at these conditions 79%, 87% and 98% of phytate was degraded, respectively. Addition of tannase enhanced reduction of phytate. Fermentation of presoaked whole beans resulted in reduction of 88% of phytate after 48 hr.     

RELATIONSHIP BETWEEN PROPERTIES OF DRY AND KCOOKED FABA BEANS (VICIA FABA L.)

A total of 155 samples of faba beans were collected immediately after harvest during 3 successive years. Eight properties of the dry deeds and six properties of the cooked beans were evaluated for all samples. Relative density, the percentages of seed coat and hydration coefficient of dry seeds were highly significantly coorelated with texture and hydration coefficient of cooked faba beans. Path coefficient analysis showed that the percentage of seed coat and hydration coefficient of dry seeds were the principal properties that affected the texture and the hydration coefficient of cooked faba beans. The cooking quality of cooked faba beans may be predicted to a certain extent by determining kpercentage of seed coats or/and hydration coeffcient of dry seeds.     

Changes in the concentration of carbohydrates during the soaking of soybeans for tempe production

Soybeans were soaked for 24h in tap water at 30°C in preparation for tempe fermentation. Soaking was conducted under conditions that give a microbial fermentation, and in the presence of antibiotics where microbial growth was inhibited. Sucrose, stachyose and raffinose were the main di- and oligosaccharides in the beans, and their concentrations decreased by 84, 65 and 50%, respectively, during soaking. Glucose, fructose and galactose were found in the soak-water along with lesser amounts of sucrose, melibiose, raffinose and stachyose. Glucose was the main substrate for microbial growth in the soak-water. The concentrations of mono-, di-and oligosaccharides in the beans and in the soak-water were determined by the activity of invertases and α-galactosidases endogenous to the beans, diffusion of the sugars into and out of the bean, and the species of micro-organism growing in the soak-water.     

COFFEE DRYING IN A ROTARY CONDUCTION-TYPE HEATING UNIT

Parchment coffee (Arabica) was dried from an initial moisture content of about 90% to 10% dry basis (db) in a recirculating rotary conduction type heating unit at controlled plenum temperatures of 100, 120 and 140C or controlled product temperatures of 50, 60, and 70C. the temperature of the plenum or moving beans could be maintained at specified levels with small variations during coffee drying experiments. the color and specific gravity of coffee beans exhibited minimum changes as a result of drying operations. the susceptibility of coffee beans to breakage decreased with the lowering of moisture and attained minimum values in the moisture content range of 20 to 30% db. the breakage susceptibility increased sharply with further reduction in moisture content. A drying model, which considered product temperature‐time history alone under different operating conditions, estimated the change in moisture content adequately. Such a model could be used for computer‐based control of the coffee drying process.     

Blanching effects on chemistry, quality and structure of green beans (cv. Moncayo)

Green beans (cv. Moncayo) were blanched at 65, 70, 75, 80, 85, 90 and 97 °C for 2.5, 5, 10, 20 and 40 min. Pectinesterase (PE) activity was highest in cell-wall-bound extracts of beans blanched at 70 °C/10 min. The lowest water-soluble pectin fraction, the highest EDTA-soluble pectin fraction and the lowest degree of esterification of the EDTA-soluble fraction were all recorded for the same temperature/time combination; these effects can therefore be attributed to PE activity. Chemical changes did not affect initial firmness of the beans, which was practically constant after blanching at 65, 70, 75 and 80 °C. Simple first-order models were adequate to establish softening kinetics for beans blanched at 85, 90 and 97 °C. In this temperature range, Kramer maximum force was the mechanical parameter that best characterised bean softening by blanching. For all temperatures, short-time blanching increased the coloration and total chlorophyll content of the samples with respect to fresh control, thus precluding the use of simple models. In the treated beans, the ascorbic acid content was consistently lower than in the control and decreased continuously with increasing time. Microphotographs showed no appreciable differences in morphology between fresh and blanched beans at 65, 70 and 75 °C, which would explain the similarity of mechanical behaviour in these samples. Blanching at 85, 90 and 97 °C caused loosening and swelling of the cell walls owing to breakdown of the pectic material, which again helps to explain the observed loss of firmness.     

Retarding Vegetable Softening by Cold Alkaline Pectin Deesterification Before Cooking

Snap beans and carrot tissues, deesterified at 1°C and pH 12.5, soften much more slowly than control tissues when cooked at neutral or slightly alkaline pH. High pH or NaCl during cooking had little effect on the degree of softening. Soaking in 0.05 M EDTA led to an 86% loss in firmness. The results were consistent with a reduction in the β-elimination depolymerization of pectin during heating as a result of deesterification in the alkali. Deesterified tissues remained susceptible to pronounced softening during cooking at pH 3.5. Potatoes, cauliflower and apples showed similar effects. Peas gave a reduced response. Beets and dry beans did not show a retardation of softening after an alkali soak.     

HYDRATION KINETICS OF LUPIN (LUPINUS ALBUS) SEEDS

The hydration kinetics of lupin (Lupinus albus) seeds was studied by soaking in water at temperatures of 20, 30, 40 and 50C (±1C) in constant‐temperature water bath for 9 to 12 h. The weight gain due to the hydration process was determined in terms of moisture content (% dry basis). Water absorption rate was high at the early stage of hydration (20–60 min depending on temperature) followed by a decreased rate and finally approaching equilibrium condition. Peleg's equation adequately described the hydration characteristics of lupin seeds under the experimental condition (R² = 0.96 to 0.99). The Peleg rate constant k₁ decreased from 2.537 to 0.241 min/%, while Peleg capacity constant k₂ increased from 0.0036 to 0.0070/% significantly (P < 0.05) with an increase in temperature from 20 to 50C, demonstrating that the water absorption rate increased and water absorption capacity decreased with increase in temperature. The temperature dependence of k₁ and k₂ was described by Arrhenius type equation with R² values of 0.98 and 0.97, respectively, and activation energy of 60.44 kJ/mol. The agreement between experimental and estimated values of the hydration data (R² = 0.97 to 0.99) confirmed that Peleg's equation could be used to describe the hydration characteristics of lupin seeds under the experimental conditions considered.     

Physico-chemical characterization of stored black beans (Phaseolus vulgaris L.)

Selected physical and chemical characteristics were studied on black beans (Phaseolus vulgaris L.) after 2 years of storage under refrigerated hypobaric conditions (RHC) and ambient conditions (AC). Black beans stored under RHC of 4.5°C, 50–60% relative humidity and atmospheric pressure of 125 mm Hg exhibited quality factors characteristic of fresh beans, such as shorter cooking time, smaller quantities of solids loss, electrolytes leached, and percentage of hardshell than beans stored at AC of 23–25°C and 30–50% relative humidity. Additionally, beans stored under RHC demonstrated greater germination rate (93%) than beans stored at AC (72%). Beans stored at AC exhibited quality factors characteristic of hard-to-cook (HTC) beans. Percentage water absorption indicated a faster initial hydration rate in beans stored under RHC compared to beans stored at AC until after 12 h of soaking, when both reached a similar hydration rate. Moisture content of beans stored under RHC was similar to that of beans prior to storage, while the moisture content of beans stored at AC was significantly lower. Crude protein, crude fat, and ash concentration of beans prior to storage and beans stored for 2 years under RHC or AC were not significantly different. The electrophoretic profile of the main protein of beans, globulin G1, was not altered by the storage conditions. The combined effect of refrigeration and hypobaric storage conditions demonstrated potential for maintaining the fresh quality of beans in storage for up to 2 years.     

Effects of Vacuum Hydration on the Incidence of Splits in Canned Kidney Beans (Phaseolus vulgaris)

Dry red kidney beans were canned using two different pretreatments: soaking for 12 hr at 20°C, and vacuum hydration for 5 min followed by soaking for 2 hr at temperatures from 45-59.1°C. Samples were then packed, processed to commercial sterility, and tested for percentage of split beans after processing. Vacuum hydration pretreatments greatly decreased the incidence and severity of splitting in the canned product and accelerated water uptake while retaining the same moisture content after soaking as the conventional soak treatment. Vacuum-hydrated beans gained less moisture during retorting than conventionally treated samples.     

Use of Hydration, Germination, and α-Galactosidase Treatments to Reduce Oligosaccharides in Dry Beans

ABSTRACT: This investigation was done to determine an energetically feasible method to reduce bean oligosaccharides (stachyose and raffinose) for large-scale bean flour production. Michigan black, red, and navy beans (all Phaseolus vulgaris ) were treated by α-galactosidase, germination, or hydration to determine treatment effects on stachyose and raffinose levels. Oligosaccharides were extracted with 70% (w/w) ethanol, and α-galactosidase was added to catalyze hydrolysis of the oligosaccharides. Enzyme treatment was for 1 h at ambient temperature (23°C). For germination, whole beans were incubated in a germinating chamber (100% humidity, 26.7°C) for 48 h. In hydration, whole beans were soaked in excess water at ambient temperature (23°C) for 5 h. Enzyme treatment resulted in 51%± 3.0%, 30%± 1.9%, and 46%± 1.9% reduction in total raffinose and stachyose for black beans, red beans, and navy beans, respectively. Germination treatment resulted in 61%± 12%, 61%± 1.9%, and 70%± 2.8% reduction in total raffinose and stachyose for black beans, red beans, and navy beans, respectively. Hydrated black beans showed a loss of 33%± 9.6%, whereas hydrated red and navy beans showed no reduction of oligosaccharides. Although germination showed the greatest reduction in bean oligosaccharides, this method may not be as cost-effective commercially as the enzyme treatment because of the time required for germination.     

Antimicrobial Activity of Peptide P34 During Thermal Processing

In the present work, the influence of pH and sodium chloride concentration on thermal stability of antimicrobial peptide P34 was evaluated under different time–temperature conditions by a 2² factorial design experiment. At sterilization conditions (121 °C for 20 min), maximum retention (36%) was obtained at pH between 5.5 and 8.5 and sodium chloride concentration between 0.4 and 0.75 mol/l. For boiling conditions (100 °C for 20 min), antimicrobial activity was about 100% combining pH between 6.0 and 8.0 and salt concentration in the range of 0.65 to 1 mol/l. At low temperature pasteurization conditions (30 min at 65 °C), antimicrobial activity was not affected within the pH range from 5.0 to 8.0. For the three time–temperature conditions tested, the antimicrobial activity was minimal at more acidic or alkaline pH. Sodium chloride concentration of 0.65 mol/l increased thermostability of the peptide P34. Combination of sodium chloride and slight alkaline pH may increase the stability of peptide P34, which is essential to the proper utilization of bacteriocins in food industry.     

Effect of storage of adzuki bean (Vigna angularis) on starch and protein properties

Differential scanning calorimetry was used to evaluate the effect of storage at 10°C, 20°C and 30°C, and 40% and 65% relative humidity (RH) on adzuki bean starch gelatinisation and protein denaturation temperatures. Storage for 6 months at an elevated storage temperature (30°C) caused increases in the starch gelatinisation onset temperature (T_o) and gelatinisation peak temperature (T_p) for both Bloodwood and Erimo varieties. Storage at 40% RH resulted in higher T_o and T_p values than storage at 65% RH. The T_o of starch from Bloodwood and Erimo beans stored for up to 1.5 months at 10°C and 65% were similar to those of fresh beans.The changes in the salt-soluble protein component were less clear cut than those of the starch. Nonetheless, protein extracted from beans stored at 40% RH exhibited significantly lower T_o and T_p values compared with those stored at 65% RH. This indicates some destabilisation of the protein at the higher RH.These results suggest that detrimental changes occur in starch and, to a lesser extent protein, of adzuki beans stored under unfavourable conditions. On the basis of these results, the best storage conditions to maintain the characteristics of fresh beans are low temperatures (e.g. 10°C) and high RH (e.g. 65%).     

FACTORS AFFECTING THE COOKING QUALITY OF FIELD PEAS (PISUM SATIVUM L.) AND WHITE BEANS (PHASEOLUS VULGARIS L.) STORED UNDER SIMULATED FARM CONDITIONS

Factors affecting the cooking, physical, chemical, and biological characteristics of field peas and white beans were studied after 147 days’ storage under northern temperate climatic conditions. Cooking time, hydration and swelling characteristics, phytate levels, fat acidity values (FAV), off-odor and visible mold development were assessed. Among the different initial moisture contents and storage temperature regimens investigated, only the highest temperature regimen (44C declining to 15C) was associated with a noticeable reduction in the cooking quality of peas and beans. Although a gradual decline was seen in the hydration and swelling characteristics of both legumes, and in phytate levels of peas stored at the 44C to 15C regimen, no single factor appeared to explain the changes in cooking quality of peas and beans stored at high temperatures. Correlation analyses indicated the association of high levels of conductivity and FAV with poor hydration characteristics and off-odor development in the two legumes.     

AMYLOLYSIS OF SORGHUM STARCH AS INFLUENCED BY CULTIVAR,GERMINATION TIME AND GELATINISATION TEMPERATURE

The susceptibility to amylolysis of starches derived from two improved Nigerian sorghum cultivars were evaluated at assay temperatures between 50°C and 75°C. Enhancement of gelatinisation rates at temperatures up to 65°C was not significant inspite of the apparent grain modification due to germination for four days. Greater starch gelatinisation rates (20–22%) were achieved in this study compared to previously reported values, suggesting possible roles for cultivar and malting methods. There was a statistical correlation between starch gelatinisation rates over the temperature range 65°C–75°C and the duration of grain germination (r=0.91 for KSV8 and r=0.5 for SK5912 starches). Gelatinisation rate and temperature were affected significantly by assay pH. The occurrence of two pH related maxima of starch gelatinisation for both cultivera at all temperatures examined indicates the possible presence of two sets of “binding forces” within the starch granules and features of starch retrogradation .     

HEAT TREATMENT AND INACTIVATION OF TRYPSIN-CHYMOTRYPSIN INHIBITORS AND LECTINS FROM BEANS (Phaseolus vulgaris L.)

This work investigates some factors affecting the inactivation of common bean trypsin inhibitor and phytohemagglutin. Trypsin inhibitor activity was totally stable to heat treatment (30 min, 97C) in the total protein extract, albumin or globulin fraction. Heat treatment of the whole beans easily inactivated the inhibitor. Heat resistance of trypsin inhibitor was intermediate in the bean flour which received the same heat treatment. Independent of sample, the inhibitor was very stable to heat treatment at neutral and acidic pH and labile under strong alkaline conditions. Heating for 30 min in boiling water at pH 12 resulted in complete inactivation of the trypsin inhibitor. Autoclaving (121C) soaked whole beans and flour for 5 min inactivated 55% of the trypsin inhibitor activity in the soaked flour and 75% in the whole beans. After autoclaving 20 min, inactivation of trypsin inhibitor was about 65% in the flour and 80% in the whole beans. The phytohemagglutinin (lectin) activity was totally destroyed in the autoclaved beans after 5 min and in the flour after 15 min.     

A cyclically pressurised soaking process for the hydration and aromatisation of cannellini beans

Hydrating beans before cooking reduces cooking time, increases their tenderness and weight and improves their appearance after cooking. In this paper, we describe a process of cyclically pressurised soaking for the rapid hydration of cannellini beans at room temperature. This hydration process is approximately ten-fold faster than the traditional soaking procedure, and the microbial load developed by the end of this process is much lower compared to that obtained using the traditional process. This bean hydration process was achieved with a new extraction technique using the Naviglio extractor, which subjected the water containing the beans to cycles of pressurisation in which the pressure values ranged between 0 (atmospheric pressure) and 10 bar. This innovative hydration process (I) reduced the time required for the complete hydration of the beans to approximately 60 min and produced a product saturated with the same final amount of moisture as the product obtained from the conventional soaking process (T) that lasts 12–20 h. The numerical simulation of the hydration process (I) has provided useful indications on how the diffusion of humidity inside the beans occurred during the pressurised soaking process. The treated beans were packaged, and organoleptic tests, including taster panel tests, were conducted. Finally, the aromatisation of the legumes was conducted in conjunction with the hydration process to introduce flavouring elements used in some famous traditional recipes for Italian cuisine.     

Modelling the effect of temperature on the hydration kinetic of adzuki beans (Vigna angularis)

The Aw reduction is a widely used technique to preserve grains, which hydration kinetics needs to be studied in order to obtain optimized processes. This work evaluated the hydration kinetic of Adzuki beans, a widely consumed grain by the oriental culture, modelling its behaviour as function of temperature. The grains were soaked in water and the moisture over the time was evaluated at temperatures of 25–70 °C. The grain behaviour during water uptake showed an initial lag phase, with a low water absorption rate. Therefore, the hydration kinetic was evaluated using a sigmoidal model (R² > 0.99). When soaking temperature was increased the hydration rate increased and both the lag phase and the moisture at the equilibrium decreased. These behaviour were, then, modelled as function of the soaking temperature (R² > 0.99). The obtained results are potentially useful for future studies on product development, food properties and process design.