Phytic acid in stored common bean seeds (Phaseolus vulgaris L.)

Four varieties of common bean seeds stored at 4°C, 80% relative humidity, for one to eight years showed no differences in proximal chemical composition, Seeds 5–6 years old absorbed more water than 1 to 4 year-old seeds. The cooking time required for five year-old seeds was 6 hours, while the fresh seeds needed 3/4-to-one hour cooking time. The most remarkable difference was in phytic acid content, which decreased 94% to 98% during long storage.     

Unavailable carbohydrates in common bean cotyledon (Phaseolus vulgaris L.) Canario group

Unavailable carbohydrates in cotyledon flour were quantified from four varieties of common bean (Phaseolus vulgaris L) belonging to the Canario group. The pectin content, as percentage of anhydrogalacturonic acid, ranged between 1.57% and 2.3%. Percentages of hemicellulose A and B were similar, with average values of 2.81% and 2.61%, respectively. The polysaccharide extracted with 10% trichloroacetic acid was determined; its yield was 3.17%. This value dropped to 2.35% when the cotyledon flour was previously hydrolyzed with polygalacturonase. The average value of cellulose was 1.36%.     

Variation in parameters related to leaf thickness in common bean (Phaseolus vulgaris L.)

Greater leaf thickness is usually associated with greater leaf carbon assimilation rate, but the tradeoff between thicker versus larger leaves also affects canopy structure and light interception. Many studies equate the ratio of dry leaf mass to area (leaf specific mass) with leaf thickness. This approximation has utility but ignores differences in true thickness due to variation in water or air content and other factors. To understand better variation in leaf thickness in common bean (Phaseolus vulgaris L.), 14 parameters related to thickness were compared for a diverse set of bean cultivars grown in three field environments in Colombia. The parameters included leaf thickness per se as measured anatomically or with a micrometer, leaf specific mass expressed on dry and fresh weight bases, leaf optical density measured at 670 nm, total leaf chlorophyll concentration expressed on a leaf area basis, leaf tissue density, and nitrogen concentration expressed on fresh and dry weight bases. Relative contributions of air, water, and dry matter to leaf thickness were also estimated. Most parameters showed large differences among lines, consistent with previous reports that cultivars from the Mesoamerican genepool have thicker leaves than those of the Andean genepool. Parameters varied greatly with environment and sampling date. The results support the need to control for leaf water content when studying leaf thickness. Furthermore, including mid and lateral rib tissue in leaf samples appeared to bias data sufficiently enough to double estimates of leaf thickness and specific mass. Based on time required for measurement and ability to detect cultivar differences, measuring leaf thickness with a micrometer and leaf optical density appeared the most promising for rapid characterization of leaf thickness.     

Preparation and antinutritional characteristics of dry bean (Phaseolus vulgaris L.) protein concentrates

Protein concentrates and starches were prepared by a wet extraction process from five dry bean (Phaseolus vulgaris L.) cultivars. The protein contents ranged from 69.7–76.4%. Concentrates prepared from dehulled beans under similar conditions had higher protein contents (80.6–87.9%). Each additional washing of the concentrates with distilled water increased their protein content. However, the protein recovery progressively decreased. The yield of starch ranged from 48.0–51.1% of the starting material. The solubility of bean proteins was minimal at pH 4.0, and under alkaline conditions, it was influenced by the tannin contents of the concentrates. Protein concentrates had lower trypsin, chymotrypsin, and amylase inhibitory activities as well as lower phytic acid and tannin contents compared to whole bean flours.     

Effect of sowing date on the growth and seed yield of common bean (Phaseolus vulgaris L.) in highland environments

Evaluations of common bean cultivars in the highlands of Mexico indicated that land races from that region experience less reduction in seed yield and seed size in late sowings than do lines from other regions. Introduced materials are of interest as sources of increased disease and pest resistance and tolerance to edaphic constraints, however. To quantify effects of sowing date and determine possible underlying causes, germplasm of diverse origins was evaluated at two sites in the highlands using multiple sowing dates. In all trials, seed yield, seed weight, harvest index and canopy dry weight decreased with late sowings. Large effects of sowing date, cultivar and their interaction were found for the four traits. The possible importance of phenology per se and of weather conditions was first examined using regression analyses. Variation in seed yield, seed weight, harvest index and canopy dry weight was more closely associated with time to maturity than with time to flowering. Of three weather variables examined, minimum temperature during seed filling revealed the strongest relations with the four traits. Few interactions of any parameter with line were significant, indicating that the cultivars did not have a strong differential response to a specific weather condition such as night temperature. Simulation analyses comparing photoperiod-sensitive and day-neutral cultivars indicated that radiation and temperature explained part of the yield reduction with late sowings. Daylength also had an influence, however, even in the day-neutral cultivar. Given that phenology had a strong effect on yield and that its inheritance is better understood than that of other physiological traits, priority should be given to understanding the genetic basis of the response of cultivar phenology to sowing date in the region.     

Genetic control of phaseolin protein expression in seeds of common bean,Phaseolus vulgaris L.

Phaseolin, the major globulin seed storage protein of common bean,Phaseolus vulgaris L., accounts for up to 50% of the total seed protein. The rapid accumulation of phaseolin in the maturing seeds begins about 14 days after flowering and continues for some 12–14 days longer. However, the amount and rate of phaseolin accumulation, related to variation in onset, length, termination, and rate of synthesis, have been shown to vary between genotypes.Only three phaseolin electrophoretic types, designated T, S, and C after the cultivars Tendergreen, Sanilac, and Contender, respectively, have been identified among over 100 cultivated accessions. The narrow ranges of molecular weights and isoelectric points of the 14 protein polypeptides of phaseolin, as well as the homology observed from peptide mapping, suggest that the phaseolin polypeptides are similar proteins. Based on the results of crosses among cultivars having the three electrophoretic patterns, the genes controlling the polypeptides of each of the phaseolin types appear to be tightly linked, inherited in a block and the alleles are codominant.Substantial variation in phaseolin content, based on estimations using rocket immunoelectrophoresis, has been found among bean lines. Although most segregating populations show continuous distributions and quantitative inheritance, some inbred backcross lines having enhanced phaseolin accumulation appear to carry a few genes with major effects. A single gene that reduces the amount of phaseolin to less than one-half of the normal levels has been identified recently in an accession of wildP. vulgaris.     

Interrelationships between certain physical and chemical properties of dry bean (Phaseolus vulgaris L.)

The interrelationships among certain physical and chemical properties of ten cultivars of dry beans (Phaseolus vulgaris L.) were investigated. The length/breadth ratio was similar (1.51–1.65) except for kidney beans (>2.0) and sanilac (1.37) cultivars. The breadth/thickness ratio ranged from 1.17–1.65. The 100-bean weight indicated a wide variation of 15.03–50.33 g. The density, bulk density, and porosity characteristics were within a narrow range of 1.18–1.36 g/cc, 68–75 g/100 cc, and 40.7–48.5%, respectively. Water uptake rates during the first 6 h of soaking at room temperature (21 °C) were characteristic of the cultivar. At the end of 24-h soaking, however, all cultivars had absorbed similar amounts of water (approximately 1 g/g bean). Leaching losses (g solids leached/100 g beans) had characteristic trends and ranged from 0.54 for cranberry to 3.46 for sanilac cultivars after 24-h soaking. Most correlations between selected chemical constituents and physical characteristics of the dry bean were relatively low.Journal Paper No. 2751 of Utah Agricultural Experiment Station and a contribution of Western Regional Project W-150.     

Studies on green beans (Phaseolus vulgaris L.)

The phytoalexins produced after the inoculation of green bean pods (Phaseolus vulgaris L.) with the spore suspension of three fungi viz.Fusarium solani, Penicillium patulum andPhytophthora megasperma were studied. Five phytoalexins were isolated and identified as phaseollin, coumestrol, kievitone, phaseollidin and 6--hydroxyphaseollin. Their identity was proved according to m.p., TLC, UV and MS by comparison with authentics. Moreover, the preliminary screening of their antifungal activity was carried out.     

Narrow row planting increases yield and suppresses weeds in common bean (Phaseolus vulgaris L.) in a semi-arid agro-ecology of Nyagatare,Rwanda

Narrow row planting has potential to increase crop growth and yield by increasing radiation interception (RI) and minimizing intra-specific competition in the crop. It reduces weed growth and competitiveness, making resources that are normally taken up by weeds available for crop uptake. The objective of this study was to assess the effect of row spacing on weed biomass, bean growth and yield in a semi arid agro-ecology at Nyagatare, Rwanda. The study was set up as a randomized complete block design in October–December 2009 and repeated in 2011. Planting patterns at a constant bean population density of 111 000 plants ha⁻¹ random planting (normal practice), narrow row planting (30 cm × 30 cm), medium row planting (45 cm × 20 cm) and wide row planting (60 cm × 15 cm) were treatments tested in this study. The narrow row square planting pattern significantly (P < 0.01) out-yielded the wide and random planting patterns by 22–31% in the wet 2009 season and by 27–70% in the dry 2011 season. Bean plant dry weight (P < 0.01) and number of pods per plant (P < 0.01) was highest in the narrow row and lowest in the random planting pattern in the dry 2011 season. Bean plant dry weight was not significantly affected (P > 0.05) in the wet 2009 season but number of pods plant⁻¹ (P < 0.001) was highest in the narrow row and lowest in the random planting pattern. Weed biomass was significantly lower (P < 0.05) in the narrow row and the random than in the medium and wide row planting patterns at 3, 6 and 9 weeks after emergence in 2009, but the random planting had the highest weed biomass in 2011. The results suggest that the effects narrow row planting in alleviating the negative impact of inter- and intra-specific competition were more strongly expressed in the dry 2011 season than the wet 2009 season when water was probably not a limiting factor to crop growth and yield. The results also indicate that narrow and equidistant planting has potential to increase bean yield by 30%–70%, when compared to random planting (normal practice) while at the same time suppressing weed growth and is recommended for smallholder farmers in Rwanda and other semi-arid areas in sub-Saharan Africa.     

Identification of sources of resistance to damping-off and early root/hypocotyl damage from Rhizoctonia solani in common bean (Phaseolus vulgaris L.)

Rhizoctonia solani causes economically important root and hypocotyl diseases in common bean throughout the world. Root health is a vital factor in plant development and root diseases would negatively influence water and nutrient uptake as well as cause direct stand reduction and root rot damage to the crop. An efficient common bean screening method to evaluate damping-off and early root/hypocotyl damage from R. solani was developed and used to identify dry bean lines with levels of resistance to this disease. Two sets of 163 and 111 lines previously evaluated for drought tolerance in Nebraska and Puerto Rico were evaluated for damping-off resistance and early root/hypocotyl damage under greenhouse conditions. Disease severity on plants was identified based on above-ground symptoms, seedling survival and root lesions using a rating scale of 1 (resistant) to 9 (susceptible). In the first set of lines representing commonly grown dry bean cultivars, germplasm and sources of damping-off resistance, the Rhizoctonia mean rating ranged from 1.7 to 3.9; Phaseolus vulgaris lines PI 310668 and PI 533249 had the highest damping-off resistance. In the second set of the best lines from a drought tolerance shuttle breeding program the Rhizoctonia mean rating was between 2.6 and 5.7. The availability of drought tolerant dry bean lines allowed the testing of the hypothesis that there was a correlation between selecting for drought tolerance and R. solani damping-off resistance. No correlation between mean disease rating and drought tolerance was found, but adapted dry bean lines such as NE14-08-176 released as SB-DT1, and NE14-08-225 were identified with moderate damping-off resistance and drought tolerance. Lines with both traits and other attributes will facilitate development of resistant bean cultivars to manage damping-off caused by R. solani.     

Differences in development of common bean (Phaseolus vulgaris L.) crops and pod fractions within a crop: I. Seed growth and maturity

Two experiments with common bean cultivars Rosecoco and Mwezi Moja aimed at increasing insight into differences in development with time of seeds from pods of different earliness classes within a crop. Pods were divided into three earliness classes (early, medium, and late) in relation to the fourth class, the overall crop. In all pod classes, cultivars and seasons, seeds achieved physiological maturity (PM: maximum dry weight) when fresh weight was at its maximum. PM was achieved at 58% seed moisture content in seeds from all pod classes and cultivars. Seeds from earlier pods tended to reach PM earlier than those from other classes. The time when seeds developed their final red purple colour pattern was a reasonable indicator of PM, though not completely accurate. Harvest maturity (HM: 20% seed moisture content) was reached earlier in earlier pods in cv. Rosecoco, but the timing was the same for all pod classes in cv. Mwezi Moja. The period for seeds to dry down from 58 to 20% moisture content was longer in seeds from earlier pods in cv. Mwezi Moja, but not in cv. Rosecoco. The course of decline in moisture content between 58 and 20% differed between pod earliness classes, but was not systematically affected by earliness. The timing of seed development in the overall crop could be explained by the timing of seed development in pods of different earliness classes. Relationships among seed moisture content and seed or pod colour in whole crops differed from those in pods of individual earliness classes.     

Limitations of corn (Zea mays) and common bean (Phaseolus vulgaris) diets as protein and calorie sources

Mixtures of 70:30 and 87:13 of corn and beans with or without vitamins, minerals, limiting amino acids and calories were fed to 5-week-old pigs to determine performance and efficiency of utilization. After 12 weeks it was shown that increasing the ratio from 87:13 to 70:30 (corn:beans) was a desirable measure as was the simultaneous supplementation with the other nutrients; individual groups of nutrients resulted in partial improvement in animal performance. None of the diets used was capable of inducing growth similar to the control groups fed a corn:soya diet. Results confirm the importance of total nutrients to obtain increased efficiency of protein utilization; furthermore, diets, such as the corn:bean diets studied, need to be improved in relation to both quality and quantity of protein.INCAP Publication I-1144     

Effect of alkali treatments on the nutritive value of common bean (Phaseolus vulgaris)

The effect of alkali treatments of common bean seeds with red seed coat on the stability of antinutritional factors such as tannins, phytates and trypsim inhibitors, vitamins such as niacin and riboflavin and on protein quality has been studied. The samples were processed by soaking and soaking and pressure cooking in alkalies such as sodium hydroxide, sodium carbonate and sodium bicarbonate. At low temperature sodium carbonate and at high temperature sodium bicarbonate were found to be most effective in the extraction of tannins. At both low and high temperatures sodium carbonate was found to be more efficient in destruction of phytates. In the case of trypsin inhibitors, extraction at both low and high temperatures with sodium bicarbonate was most effective. Sodium hydroxide treatment was found to be better as far as the retention of niacin and riboflavin was considered.     

Antinutritional factors in anasazi and other pinto beans (Phaseolus vulgaris L.)

Antinutritional factors of anasazi bean were compared to traditional pinto bean (Phaseolus vulgaris L.). Anasazi beans contained less (p<0.001) soluble and bound condensed tannins compared to pinto beans. No differences (p>0.05) in stachyose and raffinose content were found between the two bean types; verbascose was not detected at all. Significant (p<0.05) differences in lectin content were observed between anasazi and pinto bean. The lectins of anasazi beans were classified as non toxic and those of the pinto beans as toxic types. No differences (p>0.05) in inhibitor activity against human and bovine trypsin and chymotrypsin were found between the two bean types.     

Denaturation by heat,sodium dodecyl sulphate and dithiothreitol of globulins and phaseolin from dry bean (Phaseolus vulgaris L.)

The electrophoretic pattern of the untreated common bean globulin cv. Flor de Mayo had 7 protein fractions ranging from 620 to 120 kilodaltons (kd). The last molecular weight corresponds to the monomeric form. One of the objectives of the present work was to establish a comparison among denaturation by heat, sodium dodecyl sulphate (SDS) and dithiothreitol (DTT). At pH 6.0, two bands were resistant to heat treatment, after SDS treatment of the untreated globulin several bands disappeared and two new bands with 26 and 15 kd appeared. DTT did not change the electrophoretic pattern, due to the small quantity of free SH groups in the globulin. At pH 6.0, phaseolin is partly resistant to heat denaturation due to aggregation in an acidic environment. Isoelectrofocusing (IEF) and SDS polyacrylamide gel electrophoresis (SDS-PAGE) separated phaseolin into 10 protein fractions. The hypothesis is that phaseolin or globulin aggregation is due to the charge difference of fractions.     

Quick-cooking beans (Phaseolus vulgaris L.): I. Investigations on quality

Soaking three beans cultivars (Phaseolus vulgaris L.: Great Northern, kidney, and pinto) in mixed salt solution (sodium chloride 2.5% + sodium bicarbonate 1.5% + sodium tripolyphosphate 1.0% + sodium carbonate 0.5%) resulted in 80%–85% reduction in cooking time over corresponding controls. Irradiation (-rays) at 500 krads of soaked and dehydrated beans caused a reduction of nearly 50% in cooking time. Water uptake and leaching losses for each treatment during soaking at 22°, 37°, and 45°C were investigated. High temperature (37° and 45°C) and pH (9.0) caused greater water imbibition and total solid loss than at room temperature (22°C). Organoleptic evaluation revealed that quick-cooking Great Northern beans appear to be more acceptable than kidney and pinto beans. Quick-cooking cooked beans had better in vitro protein digestibility than conventionally cooked beans. Phenolic content was found to be inversely related to in vitro digestibility.Utah Agricultural Experiment Station Journal article no. 2481.     

Water uptake during cooking of dry beans (Phaseolus vulgaris L.)

Water uptake during cooking of ten dry bean (Phaseolus vulgaris L.) varieties was investigated. Water uptake during early stages of cooking was characteristic of the variety. Although the optimal cooking times varied widely (52–85 min), all the beans absorbed similar amounts of water when cooked for their optimal times. Cooking times were significantly correlated with W_{20 min} (r=–0.92) and hardness index (r=0.76) of beans. Most other physical characteristics excepting the surface area of beans were generally unrelated to theW _{20 min},W _opt, and cooking times. No significant correlation was observed between phytate content and cooking times of beans. On cooking for their respective optimal times, all varieties absorbed nearly 1.5 times their weight of water and attained a moisture content of about 65% (wet basis).     

Comparison of procedures to determine protein content of developing bean seeds (Phaseolus vulgaris)

Micro-Kjeldahl, Lowry and Bradford procedures were compared for determining the protein content ofPhaseolus vulgaris seeds during their development. Micro-Kjeldahl and biuret techniques were also compared with mature seeds of a normal and a genetically-improved bean cultivar. The protein contents of casein and soy protein isolate were as well estimated by these four methods. For many samples of both bean and food protein products large disagreements were found between micro-Kjeldahl and the other three procedures.     

Comparative study of enzymes related to proline metabolism in tepary bean (Phaseolus acutifolius) and common bean (Phaseolus vulgaris) under drought and irrigated conditions,and various urea concentrations

There are several mechanisms used by plants for survival in adverse environments such as drought, high temperature and salinity. The objective of this study was to evaluate the drought tolerance of tepary bean as a function of biochemical processes linked to isozyme synthesis and changes in enzymatic activity related to proline metabolism. Mature seeds of common beans var. flor de mayo, Phaseolus vulgaris and tepary beans Phaseolus acutifolius were grown under two water conditions (irrigation and drought), and four levels of urea. Vertical electrophoresis and spectrophotometric techniques were used to evaluate protein patterns, glutamate dehydrogenase (GDH), proline oxidase (PO) and pyrroline-5-carboxylate reductase (P5C reductase) enzyme activities. These enzymes were studied because they are directly related to protein synthesis. Electrophoretic patterns showed more proteins in tepary beans than in common beans with limited irrigation. GDH showed only one isozyme, with a molecular weight between 240 to 270 kDa. A decrease in PO activity was observed in common beans under drought stress with a value of 237 mol/min, in comparison to irrigation conditions of 580 mol/min. GDH and P5C reductase enzymes have had higher activity in common beans than in tepary beans under water stress. There was a significant difference only in glutamate dehydrogenase enzyme with respect to urea level. The results suggest that drought tolerance of tepary beans is due to biochemical processes related to proline metabolic enzymes.     

施磷水平对小麦子粒蛋白质含量及根系生理特性的影响

为明确磷肥对小麦品质及根系发育的影响及调控,以强筋小麦郑麦9023、中筋小麦周麦18号、弱筋小麦郑麦004为材料,研究了3个磷肥水平对不同筋力型小麦子粒蛋白质含量和根系数量性状及生理生化特性的影响。结果表明,增施磷肥在不同程度上增加次生根数,提高根系活力,降低根中可溶性糖含量,但高磷并不利于根系生长。次生根数在子粒灌浆期达最高值,其中,郑麦004的单株次生根数和主茎次生根数较多。根系对TTC的还原强度在拔节期达到最大值,成熟期降到最低,其中,郑麦9023对TTC的还原强度较弱。根中可溶性糖含量在冬前达到最大值,其中,周麦18号的根中可溶性糖含量较高。施磷增加周麦18号和郑麦9023的子粒蛋白质含量,但降低郑麦004的子粒蛋白质含量。