Genetic variability of cooking time in dry beans (Phaseolus vulgaris L.) related to seed coat thickness and the cotyledon cell wall

Yellow bean (Phaseolus vulgaris L.) germplasm with less dietary fiber have shorter cooking times and more bioavailable iron

Some yellow-colored market classes of dry bean (Phaseolus vulgaris L.) are valued by consumers as an easy-to-digest, fast cooking alternative to darker colored red and black beans, which in comparison generally have longer cooking times and reduced iron bioavailability. There is evidence that the cooking time of yellow beans is linked to the dietary fiber content and may also contribute to nutrient digestibility and bioavailability. Therefore, 52 fast-, moderate-, and slow-cooking yellow beans with diverse iron bioavailability from five market classes (Amarillo, Canario, Green-yellow, Manteca, and Mayocoba) were selected for total dietary fiber (TDF) analysis. TDF was measured as insoluble (IDF) + soluble (SDF) + oligosaccharides (OLIGO) using method AOAC2011.25. Wide variations in the concentrations of IDF (16.0-23.1%), SDF (1.6-7.7%), OLIGO (1.5-3.4%), and TDF (20.6-31.3%) were detected among the yellow beans with various cooking times. Lower concentrations of IDF in yellow beans were associated with shorter cooking times and higher iron bioavailability. The larger sized Andean yellow beans had more SDF than Middle American. One Mayocoba breeding line from Puerto Rico, PR1146-124, had 42% less OLIGOs than average, and may be useful for breeding low-flatulence beans for consumer acceptability. Fast cooking yellow beans provide the same SDF and OLIGO concentrations as yellow beans with longer cooking times but have the added benefit of shorter cooking times (convenience) and provide more bioavailable iron after cooking.

Hydrolysis and diffusion of raffinose oligosaccharides family products in chickpeas, lentils, and beans under different pH and temperature steeping conditions

Soaking pulses in water is a traditional practice widely used both by many households and by the food industry, and depending on the specific conditions used, can effectively reduce α-galactosides. Monitoring changes in α-galactoside content in pulses under different steeping conditions can provide insights into the degradation mechanisms and help overcome the barrier to consumption caused by digestive problems. In this study, we analyzed the impact of steeping at different temperatures (30, 45, 60, 75, and 90 °C) and at different pH (4.0, 5.0, and 6.0) on α-galactosides content in chickpeas, lentils, and beans. Our results showed that the lower the pH, the faster the α-galactosides were reduced. Moreover, steeping at lower temperatures (30 °C and 45 °C) favored hydrolysis of α-galactosides, whereas steeping at higher temperatures (60, 75, and 90 °C) favored diffusion. Soaking at 45 °C at a pH of 4.0 for 3 h resulted in acceptable levels of α-galactosides (less than 1 g/100 g), i.e. a reduction of up to 65 % in chickpeas, 85 % in lentils, and 52 % in beans.

Analyzing Cooking Efficiency of Gradoli Purgatory Beans: Effects of Dehulling, Malting, and Monovalent Carbonates

Legumes, rich in protein, fiber, and micronutrients, are increasingly popular in pulse-based and gluten-free foods despite global consumption stagnating at 21 g/day due to taste, low protein digestibility, anti-nutrients, and long cooking times. Bean resistance to cooking causes textural defects like the hardshell and hard-to-cook phenomena. The pectin-cation-phytate hypothesis explains why soaking beans in sodium salts reduces cooking time by enhancing pectin solubility in water. Gradoli Purgatory beans (GPB), from Italy's Latium region, were malted, reducing phytic acid by 32% and oligosaccharides by 63%. This study evaluated the hardness of cooked GPB seeds in various conditions, including decorticated or malted states, using a modified standard method. Cooking at 98 °C for 7-75 min on an induction hob with a water-to-seed ratio of 4 g/g was tested. Soaking was applied before cooking for conventional seeds only, followed by texture analysis. Conventional GPBs were adequately cooked if their cotyledons disintegrated upon pressing, requiring a force peak of 250 to 220 N and cooking times of 52 to 57 min. Malted, decorticated, and split GPBs cooked similarly to raw decorticated and split ones, with times of 32 and 25 min, respectively. Faster cooking was due to bean coat removal and splitting, not chemical changes. Sodium or potassium carbonate/bicarbonate at 1-2 g/L improved cooking efficiency, with 2 g/L of sodium carbonate reducing cooking time to 13 min. Higher concentrations caused non-uniform cooking. Cooking malted, decorticated, and split GPBs in sodium-carbonated water reduced greenhouse gas emissions from 561 to 368 g CO2e/kg, meeting the demand for eco-friendly and nutritionally enhanced plant protein sources.

Seed quality as a proxy of climate-ready orphan legumes: the need for a multidisciplinary and multi-actor vision

In developing countries, orphan legumes stand at the forefront in the struggle against climate change. Their high nutrient value is crucial in malnutrition and chronic diseases prevention. However, as the 'orphan' definition suggests, their seed systems are still underestimated and seed production is scanty. Seed priming is an effective, sustainable strategy to boost seed quality in orphan legumes for which up-to-date guidelines are required to guarantee reliable and reproducible results. How far are we along this path? What do we expect from seed priming? This brings to other relevant questions. What is the socio-economic relevance of orphan legumes in the Mediterranean Basin? How to potentiate a broader cultivation in specific regions? The case study of the BENEFIT-Med (Boosting technologies of orphan legumes towards resilient farming systems) project, developed by multidisciplinary research networks, envisions a roadmap for producing new knowledge and innovative technologies to improve seed productivity through priming, with the long-term objective of promoting sustainability and food security for/in the climate-sensitive regions. This review highlights the existing drawbacks that must be overcome before orphan legumes could reach the state of 'climate-ready crops'. Only by the integration of knowledge in seed biology, technology and agronomy, the barrier existing between research bench and local agricultural fields may be overcome, generating high-impact technical innovations for orphan legumes. We intend to provide a powerful message to encourage future research in line with the United Nations Agenda 2030 for Sustainable Development.

Variety-dependent accumulation of glucomannan in the starchy endosperm and aleurone cell walls of rice grains and its possible genetic basis

Plant cell wall plays important roles in the regulation of plant growth/development and affects the quality of plant-derived food and industrial materials. On the other hand, genetic variability of cell wall structure within a plant species has not been well understood. Here we show that the endosperm cell walls, including both starchy endosperm and aleurone layer, of rice grains with various genetic backgrounds are clearly classified into two groups depending on the presence/absence of β-1,4-linked glucomannan. All-or-none distribution of the glucomannan accumulation among rice varieties is very different from the varietal differences of arabinoxylan content in wheat and barley, which showed continuous distributions. Immunoelectron microscopic observation suggested that the glucomannan was synthesized in the early stage of endosperm development, but the synthesis was down-regulated during the secondary thickening process associated with the differentiation of aleurone layer. Significant amount of glucomannan in the cell walls of the glucomannan-positive varieties, i.e., 10% or more of the starchy endosperm cell walls, and its close association with the cellulose microfibril suggested possible effects on the physicochemical/biochemical properties of these cell walls. Comparative genomic analysis indicated the presence of striking differences between OsCslA12 genes of glucomannan-positive and negative rice varieties, Kitaake and Nipponbare, which seems to explain the all-or-none glucomannan cell wall trait in the rice varieties. Identification of the gene responsible for the glucomannan accumulation could lead the way to clarify the effect of the accumulation of glucomannan on the agronomic traits of rice by using genetic approaches.

Redesigning crop varieties to win the race between climate change and food security

Climate change poses daunting challenges to agricultural production and food security. Rising temperatures, shifting weather patterns, and more frequent extreme events have already demonstrated their effects on local, regional, and global agricultural systems. Crop varieties that withstand climate-related stresses and are suitable for cultivation in innovative cropping systems will be crucial to maximize risk avoidance, productivity, and profitability under climate-changed environments. We surveyed 588 expert stakeholders to predict current and novel traits that may be essential for future pearl millet, sorghum, maize, groundnut, cowpea, and common bean varieties, particularly in sub-Saharan Africa. We then review the current progress and prospects for breeding three prioritized future-essential traits for each of these crops. Experts predict that most current breeding priorities will remain important, but that rates of genetic gain must increase to keep pace with climate challenges and consumer demands. Importantly, the predicted future-essential traits include innovative breeding targets that must also be prioritized; for example, (1) optimized rhizosphere microbiome, with benefits for P, N, and water use efficiency, (2) optimized performance across or in specific cropping systems, (3) lower nighttime respiration, (4) improved stover quality, and (5) increased early vigor. We further discuss cutting-edge tools and approaches to discover, validate, and incorporate novel genetic diversity from exotic germplasm into breeding populations with unprecedented precision, accuracy, and speed. We conclude that the greatest challenge to developing crop varieties to win the race between climate change and food security might be our innovativeness in defining and boldness to breed for the traits of tomorrow.

Gene expression profiling of soaked dry beans (Phaseolus vulgaris L.) reveals cell wall modification plays a role in cooking time

Dry beans (Phaseolus vulgaris L.) are a nutritious food, but their lengthy cooking requirements are barriers to consumption. Presoaking is one strategy to reduce cooking time. Soaking allows hydration to occur prior to cooking, and enzymatic changes to pectic polysaccharides also occur during soaking that shorten the cooking time of beans. Little is known about how gene expression during soaking influences cooking times. The objectives of this study were to (1) identify gene expression patterns that are altered by soaking and (2) compare gene expression in fast-cooking and slow-cooking bean genotypes. RNA was extracted from four bean genotypes at five soaking time points (0, 3, 6, 12, and 18 h) and expression abundances were detected using Quant-seq. Differential gene expression analysis and weighted gene coexpression network analysis were used to identify candidate genes within quantitative trait loci for water uptake and cooking time. Genes related to cell wall growth and development as well as hypoxic stress were differentially expressed between the fast- and slow-cooking beans due to soaking. Candidate genes identified in the slow-cooking beans included enzymes that increase intracellular calcium concentrations and cell wall modification enzymes. The expression of cell wall-strengthening enzymes in the slow-cooking beans may increase their cooking time and ability to resist osmotic stress by preventing cell separation and water uptake in the cotyledon.

Hard-to-cook phenomenon in common legumes: Chemistry, mechanisms and utilisation

Future dietary protein demand will focus more on plant-based sources than animal-based products. In this scenario, legumes and pulses (lentils, beans, chickpeas, etc.) can play a crucial role as they are one of the richest sources of plant proteins with many health benefits. However, legume consumption is undermined due to the hard-to-cook (HTC) phenomenon, which refers to legumes that have high resistance to softening during cooking. This review provides mechanistic insight into the development of the HTC phenomenon in legumes with a special focus on common beans and their nutrition, health benefits, and hydration behaviour. Furthermore, detailed elucidation of HTC mechanisms, mainly pectin-cation-phytate hypothesis and compositional changes of macronutrients like starch, protein, lipids and micronutrients like minerals, phytochemicals and cell wall polysaccharides during HTC development are critically reviewed based on the current research findings. Finally, strategies to improve the hydration and cooking quality of beans are proposed, and a perspective is provided.

Novel insights into the role of the pectin-cation-phytate mechanism in ageing induced cooking texture changes of Red haricot beans through a texture-based classification and in situ cell wall associated mineral quantification

Utilization of common beans is greatly hampered by the hard-to-cook (HTC) defect induced by ageing of the beans under adverse storage. Large bean-to-bean variations exist in a single batch of beans. Therefore, a texture-based bean classification approach was applied in this detailed study on beans with known textures, to gain in-depth insights into the role of the pectin-cation-phytate mechanism in relation to the texture changes during subsequent cooking of Red haricot fresh and aged beans. For the first time, a correlation between the texture (exhibited after cooking) of a single bean seed before ageing (fresh) and its texture after ageing was established. Furthermore, scanning electron microscopy coupled with energy dispersive spectrometry (SEM-EDS) based in situ cell wall associated mineral quantification revealed that the cell wall associated Ca concentration was significantly positively correlated with the texture of both fresh and aged cooked Red haricot bean cotyledons, with ageing resulting in a significant enrichment of Ca at the cell wall. These additional Ca cations originate from intracellular phytate hydrolysis during ageing, which was shown to affect the texture distribution of aged beans during cooking significantly. The relocation of the mineral cations from the cell interior to the cell wall occurs mainly during storage rather than subsequent soaking of the cotyledons. In addition, the pectin-cation-phytate hypothesis of HTC was further confirmed by demethylesterification of the cell wall pectin and increased pectin-Ca interactions upon ageing of the cotyledons, finally leading to HTC development of the cotyledon tissue.

Influence of high‐pressure processing on nutritional composition and bioactive compounds of Phaseolus coccineus L

The influence of high-pressure processing (HPP) prior to cooking on nutritional composition and bioactive compounds content of four varieties of Phaseolus coccineus L. was studied. Cooking and HPP+C increased the protein content. However, minerals, total carbohydrates, ciceritol and α-galactosides were reduced. Fat was not affected by cooking but decreased after HPP+C. For dietary fiber, the behavior observed was different depending on the sample and the treatment applied. HPP+C could be considered a good processing technology to retain the advantageous lower myo-inositol phosphates isoforms and supply prebiotic oligosaccharides. The trypsin inhibitors activity was lower in the cooked and HPP+C samples; however, there were no significant differences between both thermal treatments. Thus, HPP+C reduced cooking time and preserving or improving the nutritional composition of the beans and their bioactive compounds content.

Utilizing Hydrothermal Processing to Align Structure and In Vitro Digestion Kinetics between Three Different Pulse Types

Processing results in the transformation of pulses’ structural architecture. Consequently, digestion is anticipated to emerge from the combined effect of intrinsic (matrix-dependent) and extrinsic (processed-induced) factors. In this work, we aimed to investigate the interrelated effect of intrinsic and extrinsic factors on pulses’ structural architecture and resulting digestive consequences. Three commercially relevant pulses (chickpea, pea, black bean) were selected based on reported differences in macronutrient and cell wall composition. Starch and protein digestion kinetics of hydrothermally processed whole pulses were assessed along with microstructural and physicochemical characteristics and compared to the digestion behavior of individual cotyledon cells isolated thereof. Despite different rates of hardness decay upon hydrothermal processing, the pulses reached similar residual hardness values (40 N). Aligning the pulses at the level of this macrostructural property translated into similar microstructural characteristics after mechanical disintegration (isolated cotyledon cells) with comparable yields of cotyledon cells for all pulses (41–62%). We observed that processing to equivalent microstructural properties resulted in similar starch and protein digestion kinetics, regardless of the pulse type and (prolonged) processing times. This demonstrated the capacity of (residual) hardness as a food structuring parameter in pulses. Furthermore, we illustrated that the digestive behavior of isolated cotyledon cells was representative of the digestion behavior of corresponding whole pulses, opening up perspectives for the incorporation of complete hydrothermally processed pulses as food ingredients.

Improving soaking efficiency of soybeans through sweeping frequency ultrasound assisted by parameters optimization

Soybean soaking is important to the processing of bean products, however, restricted by the long soaking time. Herein, the soybean soaking was assisted by 60 kHz sweeping frequency ultrasound (SFU). Shortening mechanism of soaking time and physicochemical properties of soybeans were analyzed. Results showed that soaking temperature of 37 °C, ultrasonic power of 60% (144 W), and soaking time of 214 min were optimum SFU-assisted parameters. The soaking time was reduced by 45.13%, and soluble protein content increased by 14.27% after SFU. Based on analysis of acoustic signals, the maximum voltage amplitude of SFU increased with the increment of oscillation periods of cavitation bubbles, which enlarged the intercellular space and size of soybean, and cell membrane permeability was enhanced by 4.37%. Unpleasant beany flavor compounds were reduced by 16.37%-47.6%. Therefore, SFU could significantly improve the soaking efficiency of soybeans and provide a theoretical basis for the processing enterprises of soybean products.

Multivariate genomic analysis and optimal contributions selection predicts high genetic gains in cooking time, iron, zinc, and grain yield in common beans in East Africa

Common bean (Phaseolus vulgaris L.) is important in African diets for protein, iron (Fe), and zinc (Zn), but traditional cultivars have long cooking time (CKT), which increases the time, energy, and health costs of cooking. Genomic selection was used to predict genomic estimated breeding values (GEBV) for grain yield (GY), CKT, Fe, and Zn in an African bean panel of 358 genotypes in a two-stage analysis. In Stage 1, best linear unbiased estimates (BLUE) for each trait were obtained from 898 genotypes across 33 field trials in East Africa. In Stage 2, BLUE in a training population of 141 genotypes were used in a multivariate genomic analysis with genome-wide single nucleotide polymorphism data from the African bean panel. Moderate to high genomic heritability was found for GY (0.45 ± 0.10), CKT (0.50 ± 0.15), Fe (0.57 ± 0.12), and Zn (0.61 ± 0.13). There were significant favorable genetic correlations between Fe and Zn (0.91 ± 0.06), GY and Fe (0.66 ± 0.17), GY and Zn (0.44 ± 0.19), CKT and Fe (-0.57 ± 0.21), and CKT and Zn (-0.67 ± 0.20). Optimal contributions selection (OCS), based on economic index of weighted GEBV for each trait, was used to design crossing within four market groups relevant to East Africa. Progeny were predicted by OCS to increase in mean GY by 12.4%, decrease in mean CKT by 9.3%, and increase in mean Fe and Zn content by 6.9 and 4.6%, respectively, with low achieved coancestry of 0.032. Genomic selection with OCS will accelerate breeding of high-yielding, biofortified, and rapid cooking African common bean cultivars.