Modelling Water Absorption in Soybean, Cowpea and Peanuts at Three Temperatures Using Peleg's Equation

Peleg's equation was used to model moisture sorption in soybean, cowpea and peanuts at 2°C, 25°C and 40°C. Peleg K₁ varied with temperature while Peleg K₂ was not relatively affected. Peleg K₂ could be used as a water absorption parameter. The lower the K₂ value, the more water was absorbed. Values of K₁ and K₂ were predicted for each of the cultivars of the legumes studied. There was no significant (P > 0.05) difference in either K₁ or K₂ value for both the dehulled and undehulled peanuts. Peleg equation with the predicted constants gave fairly good fit for water absorption in the legumes.     

WATER-ABSORPTION CHARACTERISTICS OF VARIOUS PEARL MILLET CULTIVARS AND SORGHUM GROWN IN NORTHERN NIGERIA

Ten pearl millet cultivars and one sorghum cultivar were evaluated for physical properties and chemical composition. Water‐absorption characteristics of these grains were also determined using Peleg's equation. Results indicated wide variations in thousand‐kernel weight and volume, grain hardness, percent floaters, in addition to considerable variations in protein, fat and crude fiber. Peleg's equation gave a reasonable fit to experimental data. Peleg constants K₁ were obtained for the pearl millet cultivars. Temperature dependence of the reciprocal of the Peleg constant K₁ was determined using an Arrhenius equation. Activation energies were in the range of 1.405–6.572 kJ/mol. A linear relationship was proposed to describe the relationship between the rate of absorbed water per unit change in temperature and activation energy.     

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.     

豌豆浸泡过程中的吸水动力学研究

利用Peleg模型方程和低场核磁共振技术(LF-NMR)对豌豆浸泡吸水过程进行研究,目的是通过新的角度来解释豌豆浸泡过程中水分子的动态变化,通过把豌豆浸泡在不同水合温度和不同浸泡时长的环境中,每隔1 h测定其含水量、脉冲信号幅值、弛豫时间.结果表明,在25～40℃浸泡条件下,豌豆中的含水量可以用Peleg方程进行模拟,...     

Effect of processing on water absorption and softening kinetics in chickpea (Cicer arietinumL) seeds

The processing effect on the physical properties of chickpea seeds (kabuli type cv Athenas) is reported. Soaking of chickpea seeds in different solutions (distilled water, 0·5% NaHCO₃ and 0·5% CaCl₂) is characterised by a rapid water absorption followed by a decrease in the hydration rate to saturation point. An improvement in chickpea softening rate and water absorption during cooking, with previous 12 h soaking in 0·5% NaHCO₃, was observed. The presence of Ca²⁺ ions delayed the softening process in chickpea seeds. Physicochemical changes associated to the soaking and cooking process necessary for reducing cooking time are discussed. The texturometer method was estimated as a suitable objective method for the evaluation of the cooking degree in chickpea seeds. © 1998 Society of Chemical Industry     

Characterization of protein isolates from different Indian chickpea (Cicer arietinum L.) cultivars

Protein isolates prepared by alkaline solubilization followed by isoelectric precipitation and freeze drying from desi (PBG-1, PDG-4, PDG-3, GL-769, and GPF-2) and kabuli (L-550) chickpea cultivars were evaluated for functional (water and oil absorption capacities, least gelation concentration, foaming capacity and stability) and thermal properties. Significant difference (P ? 0.05) in properties of kabuli and desi chickpea protein isolates was observed. Kabuli chickpea protein isolate showed significantly (P ? 0.05) higher ash (1.14%), protein (94.4%), L^∗, ΔE value, oil absorption capacity (OAC) and lower water absorption capacity (WAC) than their corresponding desi chickpea protein isolates. The solubility-pH profile of different protein isolates showed minimum solubility in the pH between 4.0 and 5.0 and two regions of maximum solubility at pH 2.5 and 7.0. Foaming capacity of all protein isolates increased with the increase in concentration. Kabuli chickpea protein isolate showed the highest foam stability (94.7%) after 120 min of storage. The thermal properties of protein isolates from different chickpea cultivars were studied by differential scanning calorimetry (DSC). Protein isolates from both the chickpea types differed significantly (P ? 0.05) in peak denaturation temperature (T_d) and heat of transition (ΔH). Kabuli type protein isolate exhibited lower T_d and ΔH value as compared to those from desi types. The interrelationships between characteristics of protein isolates showed a significant (P ? 0.05) negative correlation of T_d with protein content and OAC. It was also observed that cultivars with high fat content had high ΔH and lower WAC.     

Structure and Viscoelastic Properties of Starches Separated from Different Legumes

A comparison between the morphological, structural, thermal and viscoelastic properties of starches separated from pigeon pea, chickpea, field pea, kidney bean and blackgram was made. The shape of the starch granules in the different legumes varied from oval to elliptical or spherical. X-ray diffraction of the legume starches indicated a typical C-pattern (mixture of A- and B-type). Granules of blackgram and pigeon pea starch had a higher degree of crystallinity than those of field pea and kidney bean starches. Apparent amylose content of field pea, kidney bean, chickpea, blackgram and pigeon pea starch was 37.9%, 36.0%, 34.4-35.5%, 32.9-35.6% and 31.8%, respectively. Distribution of isoamylase-branched materials among the starches revealed that the proportions of long and short side chains of amylopectin ranged between 13.6-18.5% and 41.7-46.5%, respectively. Field pea and kidney bean starch had the highest apparent amylose content and the lowest amount of long side chains of amylopectin, respectively. Blackgram and pigeon pea starch possessed higher proportions of both long and short side chains of amylopectin than field pea and chickpea starches. The onset, peak and conclusion temperatures of gelatinization (T_o T_p and T_c, respectively) were determined by differential scanning calorimetry. T_o and T_c ranged from 59.3 to 77.3°C, 66.8 to 79.6°C, 55.4 to 67.6°C and 68.3 to 69.3°C, respectively, for chickpea, blackgram, field pea and kidney bean starch. The enthalpy of gelatinization (ΔH_gel) of field pea, kidney bean, chickpea, blackgram and pigeon pea starches was 3.6, 3.0, 2.6-4.2, 1.6-1.7 and 2.6 J/g, respectively. Pastes of blackgram and pigeon pea starches showed lower storage and loss shear moduli G′ than field pea, kidney bean and chickpea starches. The changes in moduli during 10 h at 10°C revealed retrogradation in the order of: field pea> kidney bean> chickpea> blackgram> pigeon pea starch. In blackgram and pigeon pea starches, the lower proportion of amylose plus intermediate fraction and higher proportion of short and long side chains of amylopectin are considered responsible for the higher crystallinity, gelatinization temperature and enthalpy of gelatinization.     

Modelling the effect of temperature on respiration rate of fresh cut papaya (Carica papaya L.) fruits

A respiration rate (RR) model based on Peleg’s equation was developed for predicting RRs of fresh cut papaya. Respiration data for fresh cut papaya at 3/4 maturity were generated at temperatures 5, 10, 15, 20, 25 and 30°C using a closed system. RRs was found to be significantly influenced by storage temperature and increased from 0.021 to 0.289 mL[O₂]/kg·h and 0.063 to 0.393 mL[CO₂]/kg·h as a function of O₂ and CO₂ gas concentrations, respectively. Peleg’s constant K ₁ and K ₂ were obtained from linear regression analysis using GraphPad Prism 5.0 software and regression coefficients have good fit with values close to unity. The model was verified to assess the capability of its predictability of the RRs over the temperatures. There was good agreement with the experimentally estimated RRs. Information derived from the model can contribute in the design of successful modified atmospheric systems for storage of fresh cut papaya.     

Relationships Between Selected Properties of Seeds,Flours, and Starches from Different Chickpea Cultivars

ABSTRACT

Five desi (PBG-1, PDG-4, PDG-3, GL-769, and GPF-2) and one kabuli type (L-550) chickpea cultivars were evaluated for their seed mass, volume, hydration capacity, swelling capacity, cooking time, and instrumental textural properties (hardness, cohesiveness, gumminess, and chewiness). Flour was prepared from these chickpea cultivars and various physicochemical and functional properties were determined. The pasting (pasting temperature, peak viscosity, breakdown, and final viscosity) and gelatinization (T _o, T _p, T _c, and ΔH _gel) properties of these flours were measured using Rapid Visco Analyzer (RVA) and Differential Scanning Calorimeter (DSC), respectively. Starch was also isolated from chickpea cultivars and evaluated for amylose content, swelling power, solubility, and syneresis values. Physicochemical, cooking, and instrumental textural properties of seeds of different chickpea cultivars were related to physicochemical, gelatinization, and pasting properties of their flours and physicochemical properties of their starches. Selected properties of chickpea seeds were significantly correlated with the properties of their starches and flours. Hardness value of soaked chickpea seeds was positively correlated to cooking time, seed mass, seed volume, hydration, and swelling capacity (p < 0.01). Water solubility index (WSI) of chickpea flours was positively correlated to seed mass, volume, hydration capacity, and hardness value (p < 0.05). Selected instrumental textural parameters of seeds had positive correlation with ΔH _gel of flours (p < 0.01). Peak viscosity of flours showed positive correlation to breakdown, final viscosity, bulk density, and negative correlation to cohesiveness of soaked seeds (p < 0.01). Final viscosity showed negative correlation to bulk density and water absorption index (WAI) (p < 0.01) of flours.     

Comparative study of the functional,thermal and pasting properties of flours from different field pea (Pisum sativum L.) and pigeon pea (Cajanus cajan L.) cultivars

Physicochemical, functional, thermal and pasting properties of flours from field pea (LFP-48 and PG-3) and pigeon pea (AL-15 and AL-201) cultivars were determined and related to each other using Pearson correlation and principal component analysis (PCA). Field pea flours (FPF) were significantly (P < 0.05) different from pigeon pea flours (PPF) in their lower ash and higher fat and protein contents. FPF also exhibited higher L^∗, ΔE value, water solubility index (WSI), oil absorption capacity (OAC), foaming capacity (FC) and lower a^∗, b^∗ value, water absorption index (WAI) and water absorption capacity (WAC) in comparison to PPF. FPF differed significantly from PPF in exhibiting lower transition temperatures (T_o, T_p, T_c), enthalpy of gelatinization (ΔH_gel), peak height index (PHI) and higher gelatinization temperature range (R). PCA showed that LFP-48 and PG-3 flours were located at the far left of the score plot with a large negative score, while the AL-15 and AL-201 flours had large positive scores in the first principal component. Several significant correlations between functional, thermal and pasting properties were revealed, both by Pearson correlation and PCA. Pasting properties of the flours, measured using the rapid visco analyzer (RVA), also differed significantly. PPF were observed to have higher pasting temperature (PT), peak viscosity (PV), trough viscosity (TV), breakdown (BV), final viscosity (FV) and lower setback viscosity (SV) as compared to FPF.     

Temperature dependent hydration kinetics of Cicer arietinum splits

This study on hydration kinetics of chickpea (Cicer arietinum) in water at different temperature was conducted to assess the adequacy of models to describe absorption phenomena during soaking. The diffusion coefficient values calculated using two different forms of Fick’s second law were all of the order of 10^?9 m²/s. Peleg, Weibull and Exponential models were fitted to the soaked sample data. Adequacy of models was determined using coefficient of determination (R²), root mean square error (RMSE) and chi-square (χ²). The variation in moisture content of chickpea splits at different temperatures during hydration depicts an initial high rate of moisture absorption in the primary phase followed by slower absorption during the relaxation or secondary phase of hydration. The linearity in the curve during the initial stages of moisture absorption showed the uptake process was diffusion controlled. The results of non-linear regression analysis of fitting the models revealed that the Peleg model described the process of hydration better than did the other two models with R² ? 99.06%, RMSE ? 2.95 and χ² ? 0.001 for all the fitted models. Temperature had a positive and significant effect on the water absorption capacities and absorption was an endothermic process.     

杏仁早餐的浸泡与脆性变化

以自制的杏仁早餐为研究对象,应用Peleg模型来描述杏仁早餐的吸水过程;Peleg模型对杏仁早餐浸泡时脆性变化也具有适用性。计算了不同温度下的Peleg方程常数K1、K2,确定了杏仁早餐的吸水动力学方程。     

Fitting Fick’s model to analyze water diffusion into chickpeas during soaking with ultrasound treatment

Fick’s model together with Arrhenius relationship were successfully used to evaluate water absorption of chickpea during soaking at a temperature range of 20-97 °C with 25 kHz 100 W, 40 kHz 100 W and 25 kHz 300 W ultrasound treatments. Use of ultrasound, increase in ultrasound power and soaking temperature significantly (P < 0.05) increased the water diffusion coefficient (D_eff) of chickpea during soaking. Average gelatinization temperature of chickpea was found as 61.47 °C. Activation energy (E_a) values of chickpea for below and above gelatinization temperature were found to be 28.69 and 9.34 kJ mol⁻¹, respectively. Ultrasound treatments significantly decreased the soaking time of chickpea.     

The physico-functional characteristics of starches from cowpea (Vigna unguiculata), pigeon pea (Cajanus cajan) and yambean (Sphenostylis stenocarpa)

Starches fractionated from cowpea (Vigna unguiculata, Ife Brown), pigeon pea (Cajanus cajan, Cita II) and yambean (Sphenostylis stenocarpa) were comparatively studied for physical and functional properties, including granule morphology, granule sizes, water absorption capacity, water–oil absorption index, swelling capacity, ionic property, bulk density and amylographic viscosities. The three legume starch granules range in diameter size from 5–57.5 μm. The water absorption capacities of all the starches were generally low at room temperature up to 70°C. Pigeon pea starch was the least susceptible to swelling while the cowpea starch was the most susceptible. The starches displayed non-ionic character, low water activity, high bulk density, water and oil absorption capacities and type C Brabender visco-amylograms at 6.2% starch-water slurry (on dry wt basis). ©     

In vitro starch digestibility,expected glycemic index,and thermal and pasting properties of flours from pea,lentil and chickpea cultivars

In vitro starch digestibility, expected glycemic index (eGI), and thermal and pasting properties of flours from pea, lentil and chickpea grown in Canada under identical environmental conditions were investigated. The protein content and gelatinization transition temperatures of lentil flour were higher than those of pea and chickpea flours. Chickpea flour showed a lower amylose content (10.8–13.5%) but higher free lipid content (6.5–7.1%) and amylose–lipid complex melting enthalpy (0.7–0.8 J/g). Significant differences among cultivars within the same species were observed with respect to swelling power, gelatinization properties, pasting properties and in vitro starch digestibility, especially chickpea flour from desi (Myles) and kabuli type (FLIP 97-101C and 97-Indian2-11). Lentil flour was hydrolyzed more slowly and to a lesser extent than pea and chickpea flours. The amount of slowly digestible starch (SDS) in chickpea flour was the highest among the pulse flours, but the resistant starch (RS) content was the lowest. The eGI of lentil flour was the lowest among the pulse flours.     

Antinutrients (phytic acid,polyphenols) and minerals (Ca,Fe) availability (in vitro) of chickpea and lentil cultivars

High yielding cultivars of chickpea (Desi and Kabuli) (Cicer arietinum) and lentil (Lens esculenta) were analysed for their total mineral content, per cent availability (in vitro) of minerals and level of antinutrients. Gora Hisari (Kabuli chickpea), Haryana channa (Desi chickpea) and La-12 (lentil) were found superior. These cultivars contain highest per cent availability (in vitro) of calcium and iron and lowest values of phytic acid and polyphenols compared to other cultivan of chickpea and lentil.     

Effect of composition on moisture sorption of delactosed permeate

Delactosed permeate (DLP) is an effluent generated after the separation of most of the proteins and lactose from cheese whey. The inability to obtain stable products with acceptable low moisture content is one of the major drawbacks to further commercial development of DLP. To determine the factors influencing the sorption behavior, DLP samples from three different dairy processing industries were characterized for their composition and sorption behavior. Sorption data were successfully fitted to the Peleg model. The relationships among the compositional elements and Peleg constants for initial sorption rate (K₁) and sorption capacity (K₂) showed total sugar, lactic acid and mineral content had a significant influence on sorption. With an increase in the lactic acid and mineral content, the K₁ and K₂ values decreased, indicating higher initial sorption rate and higher sorption capacity.     

Chemical analysis and physico-chemical properties of chickpea and lentil cultivars

Some high yielding cultivars of chickpea (Kabuli and desi) (Cicer arietinum) and lentil (Lens esculenta) were used for chemical analysis and physico-chemical properties namely protein, fat, sugars, starch, in vitro digestibility of starch and protein; seed weight, seed volume, seed density, hydration capacity, swelling capacity, water absorption capacity and cooking time. Among chickpea, Gora Hisari (Kabuli) and Haryana Chana (desi) cultivars, and among lentil LH 82-6 cultivar manifested higher contents of protein, fat, sugars, starch and in vitro digestibility of starch and protein. Values of seed volume, seed density, hydration capacity, swelling capacity and water absorption capacity were also found higher for these cultivars which might have contributed towards less cooking time.     

Relationship between physicochemical and cooking properties,and effects of cooking on antinutrients,of yellow field peas (Pisum sativum)

The relationship between the physicochemical and cooking properties of yellow peas was examined in this study. A positive correlation was found between seed weight and water hydration capacity. The Peleg model, which was modified, could be used to describe the water absorption characteristics of peas and could be used to predict the rate of water absorption in the initial water absorption period. Cooking time could be measured objectively using the Mattson cooker. Cooking time was found to decrease with an increase in water hydration capacity. Hardness of cooked peas, measured using a texture analyser, was negatively correlated with both seed weight and water hydration capacity. Seed coats had a significant effect on water hydration and cooking quality of peas. Peas with relatively thin seed coats exhibited higher water hydration capacity, shorter cooking times and softer texture after cooking. The effects of soaking and cooking on trypsin inhibitor activity (TIA) and oligosaccharide levels in peas were also studied. Cooking was more effective than soaking in reducing TIA levels and oligosaccharides (raffinose, stachyose and verbascose) in peas. Copyright © 2003 Society of Chemical Industry     

Acid phosphatase in the tubers of Dioscorea species and its purification from the white yam (D. rotundata poir)

Acid phosphatase activity was determined in 15 cultivars from four species of yam. A 12-fold purification of the enzyme from Dioscorea rotundata (cv. chikakwondo) gave a homogeneous preparation as demonstrated by polyacrylamide gel electrophoresis. This enzyme preparation has an apparent molecular weight of 115 000 ±2000 and an optimum activity at a pH of 5·20 and a temperature of 50°C. The K_m of the enzyme is 3·81 mM with disodium p-nitrophenylphosphate (p-NNP) as a substrate. The energy of activation, heat of activation, energy of inactivation and heat of inactivation are 7·0, 6·4, 4·41 and 4·34 kcal M^?1, respectively. Although it has very little activity with most organic phosphoric acid esters, it is significantly inhibited by Ca²⁺, Hg²⁺ and EDTA and activated by Mg²⁺. The enzyme has a half-life of 50,17 or 13 days, respectively, when stored at 6-8°C, 0°C or room temperature (29±2°C).