Peroxyl radical‐trapping capacity of germinated legume seeds

The legume seeds of lentil (Lens culinaris( vetch (Vicia sativa) and soybean (Glycine max, cv. Mazowia) were germinated in the dark at a constant temperature of 25°C up to 168 h (24 h×7 d). The changes in peroxyl radical‐trapping capacity (PRTC) of the processed seeds were measured and compared to those of the raw seeds. A simple method of determining the peroxyl radical‐trapping capacity based on the use of 2,2′‐azobis(2‐amidopropane) hydrochloride (ABAP) decomposition as a free radical source and the use of 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) oxidation as the reaction indicator was employed to express antioxidant properties of germinated seeds. The data show that the germinated lentil and vetch seeds were more effective than germinated soybean when their peroxyl radical‐trapping capacity was compared.     

The contents of the neuro-excitatory amino acid β-ODAP (β-N-oxalyl-l-α,β-diaminopropionic acid), and other free and protein amino acids in the seeds of different genotypes of grass pea (Lathyrus sativus L.)

The free and protein amino acids of nine different genotypes of grass pea (Lathyrus sativus L.) seeds were analysed by HPLC with pre-column PITC (phenyl isothiocyanate) derivatisation. Among the free amino acids, homoarginine was quantitatively the most important (up to 0.8% seed weight) and stable while the neuro-excitatory amino acid β-ODAP (β-N-oxalyl-l-α,β-diaminopropionic acid) showed highest variation (0.02–0.54%) in the nine genotypes examined. Among protein amino acids, glutamic acid was quantitatively most significant, followed by aspartic acid, arginine, leucine, lysine and proline. The sulphur amino acid, methionine, showed the lowest concentration in all the L. sativus genotypes, and also in lentil (Lens culinaris) and in soybean (Glycine max) seeds analysed at the same time.     

A Histological and Histochemical Study of Starch Granule Degradation in the Cotyledons of Lens culinaris

The pattern of starch granules degradation and amylase development in cotyledons of Lens culinaris Medik var. Castellana, was investigated by means of fluorescence microscopy and starch film method, respectively. Starch granules degradation in lentil cotyledons during germination started at the peripheral abaxial side and advanced towards the internal adaxial side of the cotyledon. However, amylase activity development took place from the whole periphery towards the center of the cotyledon. These results show the absence of a relationship between the zone of amylase activity and the degradation of starch granules. The absence of an embryonic axis did not affect the location of amylase activity but, on the other hand, did hinder the degradation of starch.     

Evolution and kinetics of monosaccharides,disaccharides and α-galactosides during germination of lentils

The effect of light and seed rinsing during the germination of lentil seeds (Lens culinaris var. vulgaris, cultivar Magda-20) on the level of monosaccharides, disaccharides and α-galactosides (raffinose, ciceritol and stachyose) was investigated. The total soluble sugar content corresponded to about 9% of the mature seed weight, about 65% of which was α-galactosides. Germination brought about a large decrease in α-galactosides: 18% to 40% losses after 3 days and 100% after 6 days. However, glucose, which was not detected in ungerminated seeds, as well as fructose and sucrose gradually increased during germination. The content of α-galactosides decreased more rapidly when germinating seeds were given 6 h light per day, but under these conditions there was also a major reduction in the levels of fructose, glucose and sucrose. Seeds rinsed daily showed a greater reduction of α-galactosides and an increase in the levels of fructose, glucose and sucrose. When seeds were germinated for 10 days in the dark with daily rinsing, the content of α-galactosides decreased gradually during the first 4 days and they were not detected after 6 days. Under these conditions, fructose, glucose and sucrose, which represented about 3% of the mature seed weight, started increasing after day 2 and represented more than 13% of the germinated seed dry weight after 10 days.     

Application of Fourier transform infrared spectroscopy to legume seed flour analysis

The secondary structure of legume (Phaseolus vulgaris L. and Lens culinaris L.) proteins was investigated by studying the amide I infrared absorption band in whole seed flours, before and after dry heating and autoclaving thermal treatments. The analysis procedure, set up on 7S and different model proteins, shows that the content of β-sheet structures in lentil is higher than in common bean (47% vs. 32%). The dry heating does not appreciably affect secondary structures in lentil, while it causes a reduction of β-sheets (to 13%), an increase of aggregates, and the appearance of random coil structures in common bean. The autoclaving treatment produces high amounts of aggregates in both legumes. However, in lentil, random coil structures are lower than in common bean and some β-sheet structures are still detectable. These results indicate that multimeric heat-induced complexes of legume proteins have a high stability because of the high content in β-sheet structures, in particular in lentil, which may adversely affect protein utilization.     

Firmness, seed wholeness and water uptake during the cooking of lentils (Lens culinaris cv. anicia) for 'sous vide' and catering preparations

The study aimed to optimize cooking conditions of lentils ( Lens culinaris cv. anicia ) for 'sous vide' processing and catering. the softening rate of lentil seeds during cooking in deionized water was consistent with two simultaneous first order mechanisms. the apparent activation energies of firmness breakdown and loss of integrity were 86.5 kJ mol⁻¹ and 271.3 kJ mol⁻¹, respectively. Wholeness of the lentils was better preserved when the cooking temperature did not exceed 90°C. the loss of firmness was a consequence of hydration of the seed since the regression coefficient between the logarithm of residual firmness and water uptake reached −0.93 regardless of cooking temperature and heating medium (steam or water). Thus, lentil seeds maintained their firmness and wholeness as required for 'sous vide' and catering if they were cooked below 90°C for up to 2 h. Higher temperature or longer cooking time resulted in loss of firmness and wholeness.     

Splitting and dehulling lentil (Lens culinaris): Effects of seed size and different pretreatments

A conservative estimate of 800 000 T of red-cotyledon microsperma lentil (Lens culinaris Medikus) is consumed annually after postharvest processing into split dehulled seed. This process consists of cleaning the seed of foreign matter, brief immersion in water, spin-drying, standing to temper, separation into seed size fractions, dehulling/splitting and final separation. The effects of seed size (4 and 4.5 mm fractions), immersion times (1, 5, 10 and 30 min), temperature (19° and 36°) and duration (0, 30, 60 and 120 min) of air drying, and tempering time (0 and 24 h), on the efficiency of dehulling and splitting lentil were examined. Dehulling efficiency (%) was estimated as the sum of split dehulled seed, whole dehulled seed, and whole hulled seed (whole seeds are separated for recycling to the dehuller). Dehulling efficiency was best with the small seed fraction (4 mm), an immersion time of 1 min, no air drying, and a tempering time of 24 h. The drying air temperature did not have a significant effect on dehulling efficiency. Dehulling efficiency was highest with a low seed moisture content.     

Peroxyl radical-trapping capacity of germinated legume seeds

The legume seeds of lentil (Lens culinaris), vetch (Vicia sativa) and soybean (Glycine max, cv. Mazowia) were germinated in the dark at a constant temperature of 25 degrees C up to 168 h (24 h x 7 d). The changes in peroxyl radical-trapping capacity (PRTC) of the processed seeds were measured and compared to those of the raw seeds. A simple method of determining the peroxyl radical-trapping capacity based on the use of 2,2'-azobis(2-amidopropane) hydrochloride (ABAP) decomposition as a free radical source and the use of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) oxidation as the reaction indicator was employed to express antioxidant properties of germinated seeds. The data show that the germinated lentil and vetch seeds were more effective than germinated soybean when their peroxyl radical-trapping capacity was compared.     

Effect of variety and crude protein content on dehulling quality and on the resulting chemical composition of red lentil (Lens culinaris)

BACKGROUND: Dehulling is one of the most important operations in post‐harvest handling of red lentils (Lens culinaris). However, little information is available on how variety and crude protein content affect the dehulling quality characteristics and on how dehulling affects chemical composition of red lentils. Therefore, the main objective of this work was to investigate the effect of variety and crude protein content on dehulling quality and on the resulting chemical composition of red lentils. RESULTS: Four varieties of red lentil, each with two levels of protein content, were selected for this study. Crude protein content overall ranged from 225.7 to 311.7 g kg^?1 dry matter. Results indicated that variety and crude protein content had a significant effect on dehulling efficiency (DE), powder produced, broken seeds (BRK) and hull removed. Dehulled seeds exhibited higher protein, starch, phytic acid, stachyose and verbascose content, but lower TIA, tannin, sucrose and raffinose content than raw seeds. CONCLUSION: Variety and protein content had a significant effect on DE. Dehulling affected chemical composition of lentils. DE was positively correlated with starch content but negatively correlated with protein and crude fiber content of raw seeds. Information gathered from the study will be useful for lentil breeders, processors and marketers. Copyright © 2008 Society of Chemical Industry     

Species Identification of Beans, Peas and Other Legumes by RAPD-PCR after DNA Isolation using Membrane Columns

Forty legume seed samples representing 11 species were selected to investigate the identification of food legume species by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). Template DNA was extracted from seed meal and purified using a commercial membrane column kit. Amplification was performed with commercial RAPD analysis beads and six commercially available decamer nucleotide primers. Electrophoresis of the amplicons on polyacrylamide gels and subsequent silver staining resulted in RAPD profiles from all samples of one species with a given primer that differed from those of the other species studied. Unambiguous identification of six food legume species, common beans (Phaseolus vulgaris), soybeans (Glycine max), peas (Pisum sativum), chickpeas (Cicer arietinum), lentils (Lens culinaris), and alfalfa (Medicago sativa), was obtained applying three of the primers. The technique may also be suitable to identify the remaining five species investigated, scarlet runner beans (Phaseolus coccineus), lima beans (P. lunatus), green gram (Vigna radiata), broadbeans (Vicia faba), and blue lupin seeds (Lupinus angustifolius). Using a standard protocol, amplification with Taq DNA polymerase instead of RAPD beads generated RAPD profiles only from soybeans, peas, two of four chickpea samples, green gram, and lupin seeds.     

Ultrastructure of Starch Grain Breakdown in Cotyledon Cells of Germinating Lentil Seeds

Fine structural changes associated with the breakdown of starch grains in the storage parenchyma cells of the cotyledons of Lens culinaris seeds during germination are described. In the initial germination phases each starch grain is found inside a double membrane. In more advanced states of germination (8–12 days) the starch grains show erosion from within, leading to the formation of a central cavity surrounded by irregular starch fragments. During this process the starch grain maintains its external shape. Following this it was possible to observe starch fragments dispersed throughout the cytoplasm.     

Lentil Starch Content and its Microscopical Structure as Influenced by Natural Fermentation

Lentil seeds (Lens culinaris var. vulgaris, cultivar Magda-20) were allowed to ferment naturally at different lentil flour concentrations (79 g/L, 150 g/L and 221 g/L) and temperatures (28 °C, 35 °C and 42 °C). During fermentation, samples were taken at 24 h intervals. The changes in starch content in all samples were studied. Scanning electron microscopy (SEM) was used to investigate changes in samples fermented for 96 h at two different concentrations (79 g/L and 221 g/L) and two different temperatures (28 °C and 42 °C). A considerable decrease in starch content was observed at 0 h of fermentation, defined as the time when the lentil flour was completly suspended at the established temperature. Once fermentation began, flour concentration and temperature modified starch content. Fermentation brought about a general decrease in starch content and a 32—37 % dry matter content was found in the samples after 96 h. Microscopical studies showed that endocorrosion, i.e., breakdown starting from the center of starch granules, was the main pattern observed during lentil fermentation.     

Afterglow of atmospheric non-thermal plasma for disinfection of lentil seeds from Botrytis Grey Mould

Seed-borne fungal diseases of grains are a serious threat to grain crops' yield due to lack of either resistant crop varieties or dependence on fungicides. Therefore, there is a growing demand to develop sustainable technologies for crop protection. In the present study, an atmospheric microwave plasma was employed to eradicate Botrytis cinerea from lentil seeds. Argon, air and a combination of them were applied to create the plasma. There was a 41% reduction in the percentage of artificially contaminated seeds (with an initial contaminated seed percentage of 95.8%) after 100 s treatment of 2.5 g of lentil seeds with the afterglow of air plasma followed by 24-h holding time. A 32.3% reduction occurred when a 30% air/70% Argon was applied for 10 s and 60 min of holding time. The holding time of 24 h increased catalase activity from 0.8 to 1.1 mM H₂O₂ mg⁻¹ min⁻¹ that was an indicator of early plant immune system fortification. This also changed seeds' colour toward redness and yellowness. Conclusively, the afterglow of microwave plasma could be considered as a part of integrated disease management in lentil crops.     

Influence of cooking and dehulling on nutritional composition of several varieties of lentils (Lens culinaris)

The effect of cooking and dehulling on nutrients and anti-nutritional factors of several varieties of lentils (Lens culinaris) was investigated. Significant (p < 0.05) variations existed among the lentil varieties with respect to their crude protein, starch, ash, soluble dietary fiber (SDF), insoluble dietary fiber (IDF), total dietary fiber (TDF), resistant starch (RS), trypsin inhibitor activity (TIA), minerals, phytic acid, tannins, sucrose and oligosaccharides (raffinose, stachyose and verbascose) content. Cooking lentils in boiling water significantly increased protein, starch, IDF, TDF, resistant starch, Ca, Cu and Mn content, whereas reduced ash, Fe, K, Mg, P, Zn, TIA, phytic acid, tannins, sucrose and oligosaccharides were observed. Dehulling (removal of seed coat) resulted in a significant increase in protein, starch, resistant starch, K, P, phytic acid, stachyose and verbascose content, however, a significant decrease in SDF, IDF, TDF, Ca, Cu, Fe, Mg, Mn and tannin content was observed.     

Natural fermentation of lentils

Lentil (Lens culinaris var. vulgaris) flour was naturally fermented for 4 days at different temperatures (28°C, 35°C and 42°C) and concentrations (79 g/1, 150 g/1 and 221 g/1). Samples were analysed to establish the changes of total protein content and in vitro protein digestibility, trypsin inhibitor activity (TIA) and phenolic compound content during natural fermentation of lentils. The preparation of lentil flour suspensions to be fermented caused a slight increase in total protein and in vitro protein digestibility content, a decrease of TIA and a sharp decrease the tannin/catechin ratio. During the whole fermentation procedure, the minimum initial lentil concentration and temperature used (79 g/1, 28°C) achieved the maximum protein content and the lowest tannin/catechin ratio. The TIA was more affected by temperature than by concentration, and a 62.5% reduction was observed at 42°C and 79 g/1.     

A preliminary study on the effect of germination on saponin content and composition of lentils and chickpeas

Two cultivars of chickpeas (Cicer arietinum) and one cultivar of lentils (Lens culinaris) were subjected to germination in the dark for 6 days at 20°C. Soyasaponin VI, also known as soyasaponinβg, a DDMP- (2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one-) conjugated form of soyasaponin I, was the only saponin detected in both the unprocessed and germinated seed. No significant changes in saponin content were observed for chickpeas or lentils after a 6-day germination.     

Genetic Variability for Vitamin B9 and Total Dietary Fiber in Lentil (Lens culinaris L.) Cultivars

The present study was conducted to determine the genetic variability of two major health-promoting bioactive components in lentil (lens culinaris L.) cultivars. The total dietary fiber content in lentil genotypes was analyzed using a combination of enzymatic and gravimetric methods utilizing the Total Dietary Fiber Assay Kit (Sigma Chemicals, St. Louis, USA). The total dietary fiber varied significantly in the range of 10 ± 1 to 21 ± 1 g/100 g lentil dry seed weight with an average of 15.0 g/100 g lentil dry seed weight (p < 0.1). Further, a significant genotypic difference was also recorded in the lentil genotypes (p < 0.1) for folate content which was estimated using the trienzyme extraction and high-performance liquid chromatography method with an average value of 222 µg/100 g lentil dry seed weight. The range of variability for folate content was 114 ± 3 to 330 ± 7 µg/100 g dry seed weight, except in one of the genotype IG-163, where the folate content was recorded as high as 448 ± 7 µg/100 g dry seed weight. The mean total dietary fiber and folate content of Mediterranean landraces of lentil was higher (18 g/100 g and 247 µg/100 g lentil dry seed weight) as compared to the other genotypes (15 g/100 g and 198 µg/100 g lentil dry seed weight), respectively.     

Assessment of in vitro antioxidant capacity of the seed coat and the cotyledon of legumes in relation to their phenolic contents

Methanolic extracts of the seed coat and the cotyledon of two varieties of lentils (Lens culinaris L.) and two varieties of dark peas (Pisum sativum L.), were analysed for their antioxidant capacities (EC₅₀), in the form of free radical-scavenging activities. Huge differences have been observed in the antioxidant capacity in the seed coat and the cotyledon in both legumes. The seed coat, in which are located, principally, phenolic compounds with flavonoid structures, presents higher antioxidant activity than the cotyledon in lentils and peas, showing differences in both species but not very large differences between varieties. An analysis of principal components was applied to the results in order to relate the antioxidant capacity of these legumes with their phenolic composition previously established by the authors.     

Effect of Germination,under Different Environmental Conditions,on Saponins,Phytic Acid and Tannins in Lentils (Lens culinaris)

The effect of germination conditions on some antinutrients of Lens culinaris var Magda 20 seeds were studied. The seeds were germinated at 20°C under variable conditions of time, water and light. Quantitative analyses of the soyasapogenols, inositol phosphates and tannins were carried out by capillary gas chromatography, high-performance liquid chromatography and spectrophotometric techniques respectively. Germinated seeds at day 6 contained higher levels soyasapogenol B than the controls, whereas in general the tannin content was reduced. Total phytic acid amounts did not decrease after 3 days of germination but was greatly reduced after 6 days. This work shows that the optimal conditions to reduce some antinutritional factors (tannins and phytic acid) in lentils were 6 days of seed germination in dark and with alternate watering. Therefore, germination conditions offer a good opportunity to improve the nutritional quality of lentils. © 1997 SCI.     

Natural fermentation of lentils Influence of time, temperature and flour concentration on the kinetics of thiamin, riboflavin and niacin

Lentils (Lens culinaris, var. vulgaris cultivar Magda-20) were naturally fermented for 96 h at different lentil flour concentrations (79, 150 and 221 g/l) and temperatures (28, 35 and 42°C). During fermentation, samples were taken at 24-h intervals and the changes in thiamin (vitamin B₁), riboflavin (vitamin B₂) and total and available niacin (vitamin B₃) were investigated. Preparation of the lentil flour suspension to be fermented (i.e. the process of mixing the flour and sterilized tap water) caused an increase of the available niacin content in all batches, while changes in thiamin and riboflavin content were related to the conditions in which the preparation of the suspensions was carried out. The whole natural fermentation process (from the raw state to after 96 h of fermentation), either did not affect or produced a slight decrease in the thiamin content of lentils. In contrast, riboflavin, available niacin and total niacin contents increased throughout the 96 h period, which ended with a 35?–?82% increase of riboflavin, a 24?–?91% increase of available niacin and a 20?–?58% increase of total niacin. The temperature during the fermentation procedure had significant effect on the levels of thiamin and riboflavin in fermented lentils. To obtain lentil flours with an improved amount of riboflavin and available niacin with a minimum loss of thiamin, the natural fermentation of lentils should be carried out for 96 h at 42°C and with a lentil flour concentration of 221 g/l.