Nutritional ranking of 30 Brazilian genotypes of cowpeas including determination of antioxidant capacity and vitamins

Assessment of Protein Quality and Nutritional Characteristics of Commonly Consumed Pulses in the Caribbean Diet by Different In Vitro Assays

Pulses, the dried seeds of leguminous plants, form an important part of the diets of many cultures, including Caribbean cuisine, and are a rich source of protein, carbohydrates, and antioxidants while being low in fats. This study examined the effect of a traditional home-cooking method on the nutritional characteristics of pulses commonly consumed in the Caribbean: red kidney beans and cranberry beans (Phaseolus vulgaris L.), cowpeas (Vigna unguiculata L.), and pigeon peas (Cajanus cajan L.). Protein quality, determined via three in vitro protein digestibility methods, starch, and phenolic content were determined in pre- and post-cooked samples using established methods. Pulses contained 20-26% protein, and cooking improved protein digestibility on average by 14.0 ± 2.5% (p < 0.05). However, notable differences in digestibility were observed: it was higher in static assays (pH-Drop and pH-Stat) than in the two-step digestibility assay. Average protein digestibility-corrected amino acid score (IVPDCAAS) among cooked pulses was 0.81 ± 0.14, with the highest in cranberry bean (0.82) and cowpea (0.88). Cooking modified pulse starch profiles by increasing total digestible starch. However, resistant starch and slowly digestible starch fractions accounted for approximately 20-25% of total cooked starch content. While total phenolic content (TPC) and antioxidant activity were reduced with cooking, they were within expected ranges for cooked pulse flours; however, they were higher in bean (P. vulgaris) varieties than cowpea and pigeon pea. These findings support the promotion of increased pulse consumption in Caribbean diets. Home cooking is a simple method to enhance pulse protein quality through enhancing digestibility; however, in vitro protein digestibility assays may require further standardization.

Prospects on emerging eco-friendly and innovative technologies to add value to dry bean proteins

The world's growing population and evolving food habits have created a need for alternative plant protein sources, with pulses playing a crucial role as healthy staple foods. Dry beans are high-protein pulses rich in essential amino acids like lysine and bioactive peptides. They have gathered attention for their nutritional quality and potential health benefits concerning metabolic syndrome. This review highlights dry bean proteins' nutritional quality, health benefits, and limitations, focusing on recent eco-friendly emerging technologies for their obtaining and functionalization. Antinutritional factors (ANFs) in bean proteins can affect their in vitro protein digestibility (IVPD), and lectins have been identified as potential allergens. Recently, eco-friendly emerging technologies such as ultrasound, microwaves, subcritical fluids, high-hydrostatic pressure, enzyme technology, and dry fractionation methods have been explored for extracting and functionalizing dry bean proteins. These technologies have shown promise in reducing ANFs, improving IVPD, and modifying allergen epitopes. Additionally, they enhance the techno-functional properties of bean proteins, making them more soluble, emulsifying, foaming, and gel-forming, with enhanced water and oil-holding capacities. By utilizing emerging innovative technologies, protein recovery from dry beans and the development of protein isolates can meet the demand for alternative protein sources while being eco-friendly, safe, and efficient.

Cooking properties and nutrient retention of biofortified common bean (Phaseolus vulgaris) varieties: The case of Burundi

Introduction

Current research on micronutrient deficiency indicates positive outcomes associated with utilizing biofortified beans in mitigating nutrition-related iron and zinc deficiencies, primarily in Sub-Saharan Africa. The common bean is however not palatable in its raw state and requires cooking before consumption. Existing research on the cooking qualities and nutrient retention of these novel biofortified common bean varieties is nonetheless scant, notably in Burundi.

Materials and methods

This study determined water absorption capacity, cooking yield, cooking time, and iron and zinc retention of 9 biofortified common bean varieties with Kinure, a traditional non-biofortified variety, as the control. The study employed a 10 × 2 completely randomized design in a factorial arrangement. The first factor was bean varieties with ten levels, and the second was pre-treatment with two levels, soaking and not soaking. Standard methods were used to analyze cooking properties and mineral retention, and experiments replicated thrice. Data analysis was conducted at a 95% confidence level and included Analysis of Variance and t-test comparison studies. Post-hoc analysis was performed using Tukey's Honestly Significant Difference.

Results and discussion

Cooking properties and mineral retention varied significantly between soaked and unsoaked bean varieties (P &lt; 0.05) and in comparison, to Kinure (P &lt; 0.05 and P &lt; 0.001). Water absorption capacity varied from 64.51% to 116.3%. Soaked beans recorded half the total cooking time needed to cook unsoaked beans (77.62 versus 156.86 minutes), had higher cooking yields (289.77% versus 259.82%), and reduced Fe (121.58 versus 167.8%) and Zn (127.74% versus 145.15%) retention. Compared to Kinure, soaking resulted in longer cooking times, lower cooking yields in the biofortified common beans, and an insignificant effect on their zinc retention. A significant correlation between iron and zinc retention (r = 0.445), water absorption capacity and iron retention (r = −0.0425) and water absorption capacity and zinc retention (r = −0.477) were recorded. Three clusters were also observed; iron and zinc retention, cooking yields, and water absorption capacity, and cooking time. It was observed that, soaking common beans before cooking reduces cooking time and increases cooking yield in both biofortified and traditional common bean varieties. Moreover, biofortified common beans are a good source of iron and zinc and could considerably alleviate micronutrient deficiencies, particularly in developing countries.

Evaluation of adaptability and stability for iron, zinc and protein content in cowpea genotypes using GGE biplot approach

Cowpea is a widely cultivated crop in the world. Biofortification strategies aim to reduce mineral and protein deficiencies, especially among the poorest people. The aim of this study was to estimate adaptability and stability of cowpea genotypes for iron, zinc and protein contents, through GGE biplot analysis. Twenty cowpea genotypes were evaluated in the municipalities of Piauí Monsenhor Hipólito, Pio IX and São Miguel do Tapuio, under rainfed conditions. The experimental design was a randomized block design with four replications. The traits evaluated were grain yield, iron, zinc and protein contents in dry grains. Iron (Fe) and zinc (Zn) were determined by flame atomic absorption spectrophotometer, and protein contents by Kjeldahl methods. Adaptability and stability were evaluated by GGE biplot analyses. The means of the experiments were 1,209.1 kg ha^-1, 51.1 mg kg^-1, 46.8 mg kg^-1 and 24.3% for grain yield, Fe, Zn and protein contents, respectively. The joint analysis of variance showed significant difference (p < 0.05) for the effect of interaction genotypes by environments for Fe, Zn and protein contents. The lines G6 and G8 were the most promising for grain yield, mineral and protein content through adaptability and stability by GGE biplot approach.

Cowpea Immature Pods and Grains Evaluation: An Opportunity for Different Food Sources

Currently, the sustainability of agro-food systems is one of the major challenges for agriculture and the introduction of new pulse-based products can be a good opportunity to face this challenge. Cowpea (Vigna unguiculata L. Walp.) is a nutritionally important crop and has the particularity that the aerial section of the plant is entirely edible. The current research determines the nutritional composition of the alternative cowpea food sources immature pods and grains comparatively to dry grains through the evaluation of protein, minerals and different polyphenolic contents, and antioxidant capacity. Ten cowpea genotypes were analyzed during two harvest seasons. Cowpea immature pods and grains revealed high levels of total protein and K, Ca, Zn and Fe contents. In general, most of the genotypes produced cowpea of high nutritional value, with a high variation observed between them. Our results showed the potential of the introduction of new cowpea new products in the market allowing a healthy and variable diet and at the same time a better use of the crop under the scenario of climate change.

Ensuring Global Food Security by Improving Protein Content in Major Grain Legumes Using Breeding and 'Omics' Tools

Grain legumes are a rich source of dietary protein for millions of people globally and thus a key driver for securing global food security. Legume plant-based 'dietary protein' biofortification is an economic strategy for alleviating the menace of rising malnutrition-related problems and hidden hunger. Malnutrition from protein deficiency is predominant in human populations with an insufficient daily intake of animal protein/dietary protein due to economic limitations, especially in developing countries. Therefore, enhancing grain legume protein content will help eradicate protein-related malnutrition problems in low-income and underprivileged countries. Here, we review the exploitable genetic variability for grain protein content in various major grain legumes for improving the protein content of high-yielding, low-protein genotypes. We highlight classical genetics-based inheritance of protein content in various legumes and discuss advances in molecular marker technology that have enabled us to underpin various quantitative trait loci controlling seed protein content (SPC) in biparental-based mapping populations and genome-wide association studies. We also review the progress of functional genomics in deciphering the underlying candidate gene(s) controlling SPC in various grain legumes and the role of proteomics and metabolomics in shedding light on the accumulation of various novel proteins and metabolites in high-protein legume genotypes. Lastly, we detail the scope of genomic selection, high-throughput phenotyping, emerging genome editing tools, and speed breeding protocols for enhancing SPC in grain legumes to achieve legume-based dietary protein security and thus reduce the global hunger risk.

Breeding of Vegetable Cowpea for Nutrition and Climate Resilience in Sub-Saharan Africa: Progress, Opportunities, and Challenges

Currently, the world population is increasing, and humanity is facing food and nutritional scarcity. Climate change and variability are a major threat to global food and nutritional security, reducing crop productivity in the tropical and subtropical regions of the globe. Cowpea has the potential to make a significant contribution to global food and nutritional security. In addition, it can be part of a sustainable food system, being a genetic resource for future crop improvement, contributing to resilience and improving agricultural sustainability under climate change conditions. In malnutrition prone regions of sub-Saharan Africa (SSA) countries, cowpea has become a strategic dryland legume crop for addressing food insecurity and malnutrition. Therefore, this review aims to assess the contribution of cowpea to SSA countries as a climate-resilient crop and the existing production challenges and perspectives. Cowpea leaves and immature pods are rich in diverse nutrients, with high levels of protein, vitamins, macro and micronutrients, minerals, fiber, and carbohydrates compared to its grain. In addition, cowpea is truly a multifunctional crop for maintaining good health and for reducing non-communicable human diseases. However, as a leafy vegetable, cowpea has not been researched and promoted sufficiently because it has not been promoted as a food security crop due to its low yield potential, susceptibility to biotic and abiotic stresses, quality assurance issues, policy regulation, and cultural beliefs (it is considered a livestock feed). The development of superior cowpea as a leafy vegetable can be approached in different ways, such as conventional breeding and gene stacking, speed breeding, mutation breeding, space breeding, demand-led breeding, a pan-omics approach, and local government policies. The successful breeding of cowpea genotypes that are high-yielding with a good nutritional value as well as having resistance to biotics and tolerant to abiotic stress could also be used to address food security and malnutrition-related challenges in sub-Saharan Africa.

Resistance of Cowpea Genotypes to Spodoptera frugiperda (Lepidoptera: Noctuidae) and Its Relationship to Resistance-Related Enzymes

Spodoptera frugiperda (J.E. Smith) can attack cowpea plants (Vigna unguiculata [L.] Walp.) (Fabales: Fabaceae) in any growth stage but attacks primarily in the first days after plant emergence, when the plants are more sensitive to defoliation. This study was carried out to evaluate the resistance to S. frugiperda in six cowpea genotypes, of which four were cultivars (BRS Tapahium, BRS Tumucumaque, Fradinho, and Miranda), and two were landraces (Juti and Nioaque), in three different experiments. In the first experiment, adult emergence, adult weight, adult longevity, larva to adult period, numbers of injured leaves per plant canopy (upper, middle, and lower), and reduction in plant dry matter were assessed. In the second experiment, the oviposition preference of S. frugiperda for the different cowpea genotypes was evaluated under free-choice conditions. In the third experiment, levels of peroxidase (POD), superoxide dismutase (SOD), and protein content in cowpea leaves were assessed. Insects fed on landrace Juti plants showed low adult emergence, yielded a lower fitness index, and caused less plant dry matter reduction. In addition, plants of landrace Juti were less preferred for oviposition. Overall, Juti plants showed higher resistance levels in all three resistance categories and higher levels of POD and SOD in S. frugiperda injured leaves, in addition to a lower protein content. Juti will be tested in field conditions, followed by molecular characterization. This will provide additional information about its potential as an S. frugiperda resistance source in plant breeding programs.

Protein, Phytate and Minerals in Grains of Commercial Cowpea Genotypes

The objective of this study was to investigate and characterize cowpea (Vigna unguiculata) genotypes for total grain protein content, storage protein fractions (globulin, albumin, prolamin, basic and acid glutelins), and phytate and minerals contents. Eighteen cowpea genotypes were selected. Total grain protein content varied from 21.4% to 29.2%, for BRS Marataoã and Paulistinha genotypes, respectively. The variation in the concentration of each protein fraction was significant (P<0.05) only for glutelins (basic and acid). The genotypes studied exhibited great similarity in the PAGE electrophoretic profile of the grain protein fractions and also in the mineral content. BRS Paraguaçu genotype exhibited higher Zn content than thegenotypes that have been previously recommended for this characteristic. The lowest phytate grain content was observed in four of the 18 genotypes studied, which also exhibited high protein contents. Although the results did not converge to the selection of a few genotypes, some specific differences were detected that which may be further explored. Considering total grain protein, mineral and phytate contents, the genotype Paulistinha revealed a better balance unveiling high grain total protein content, low grain phytate content and more homogeneous mineral composition.

Natural Fermentation of Cowpea (Vigna unguiculata) Flour Improves the Nutritive Utilization of Indispensable Amino Acids and Phosphorus by Growing Rats

Cowpea (Vigna unguiculata) is among the most cultivated legumes, with interesting agronomic and environmental properties, and great potential as a nutritious food. The nutritional value of cowpea can be improved by technological processing. In this study, we showed that natural fermentation improved bioavailability of protein, amino acids, and dietary essential minerals from cowpea in growing rats, thus strengthening its potential value as functional food or food supplement. Forty Wistar albino rats (48 ± 1.8 g), were fed one of four experimental diets (n = 10 rats per diet): casein, raw cowpea, fermented cowpea or fermented and autoclaved cowpea. Despite lower growth indices of raw and fermented cowpea protein (PER, FTI) than casein, fermentation enhanced apparent digestibility of arginine, leucine, lysine, methionine, phenylalanine, tyrosine, and valine, and true digestibility of essential amino acids, except for tyrosine and valine, compared to raw cowpea. On the other hand, autoclaving of fermented cowpea flour decreased apparent, as did true digestibility of sulfur amino acids. Regarding the nutritive utilization of dietary essential minerals, Vigna unguiculata was a good source of available P, Mg, and K, while fermentation significantly improved the availability of P. Overall, cowpea was a good source of digestible essential amino acids and minerals and fermentation significantly improved its nutritional value that was not further enhanced by autoclaving.

Heat treatments of peptides from oyster (Crassostrea gigas) and the impact on their digestibility and angiotensin I converting enzyme inhibitory activity

The changes of protein digestibility, the peptides in the digestive juice and angiotensin I converting enzyme (ACE) inhibitory activity after heating of oysters were investigated. The digestibility of raw oysters was 71.1%, and that of oysters heated at 100 °C was 67.9%. A total of 169 and 370 peptides were identified from the digestion of raw oysters and heated oysters, respectively. According to UPLC-Q-TOF-MS spectra, the peptides with a molecular weight below 2000 Da accounted for 87.6% of the total peptides of raw oysters and 94% of heated oysters. Testing the ACE inhibitory activity in vitro, the IC₅₀ values of raw oyster and cooked oyster were 6.77 μg/mL and 3.34 μg/mL, respectively. Taken together, the results showed that heated oysters could produce more active peptides and provide ACE inhibitory activity.

A review of the contribution of cowpea leaves to food and nutrition security in East Africa

Cowpea leaf is among the African indigenous vegetables that have been recommended for possible alleviation of food and nutrition insecurity in sub-Saharan Africa (SSA). The vegetable is rich in micronutrients including iron and vitamin A whose deficiencies are prevalent in SSA. Considering the limitation of seasonal availability, preservation techniques have been adopted to enhance availability with little success. This review aims at highlighting the contribution of cowpeas leaves to food and nutrition security as well as research gaps that must be addressed to promote the utilization of value-added forms that would have extended effect of improving its production and consumption. It was found that preserved and fresh cowpea leaves were rich in beta-carotene and iron in the ranges of 0.25-36.55 and 0.17-75.00 mg/100 g dry weight, respectively. The proportion of rural households incorporating the vegetable in its various forms in the region can be as high as 30%. With adequate utilization, the vegetable provided up to ≥ 75% and 25% of RDAs for vitamin A and iron, respectively, of children aged 4-8. However, the utilization of preserved forms faced a limitation for a deviation of up to 30% in their sensory scores and decreased nutrient content as compared to the fresh ones hugely hindered their market penetration. Utilization of novel processing techniques incorporating concept of hurdle technology can help address these quality losses. In conclusion, preservation of cowpea leaves should seek not only to enhance the shelf-life, but also to enhance acceptability of the products with a view of increased utilization.

Effect of cowpea flour processing on the chemical properties and acceptability of a novel cowpea blended maize porridge

Childhood growth stunting is a pervasive problem in Malawi and is in large part due to low quality complementary foods and chronic gut inflammation. Introducing legumes such as cowpea (Vigna unguiculata) into the complementary diet has the potential to improve childhood growth by improving diet quality through improvements in macro- and micronutrients and also by reducing gut inflammation. However, cowpea is relatively underutilized in complementary feeding in Malawi due to its strong taste, long processing time, and high energy requirements for processing. Effective utilization of cowpea in complementary feeding requires processing which may affect chemical composition as well as sensory quality. The present study evaluated the effect of processing on the retention of zinc, crude fibre, and flavonoid in roasted, boiled, and dehulled cowpea flours, and assessed the acceptability of maize porridge (70%) enriched with one of the three cowpea flours (30%). Roasting, dehulling, and boiling did not have any effect on zinc content. Crude fibre content increased after processing by all methods. Processing had no effect on measurable flavonoids. Roasted, boiled, and dehulled cowpea blended maize porridges were acceptable to children with mean quantities of leftover food of less than 3g from the given 100g. Caregivers also rated the blended flours to be highly acceptable to them as well, with maize porridge blended with dehulled cowpea flour the most acceptable to both children and caregivers. These results demonstrate that cowpea flour, processed by any of these three different methods, could serve as a useful addition to maize porridge for complementary feeding of children in sub-Saharan Africa.

Evaluating the freezing impact on the proximate composition of immature cowpea (Vigna unguiculata L.) pods: classical versus spectroscopic approaches

BACKGROUND

Freezing represents a common conservation practice regarding vegetal foodstuffs. Since compositional features need to be monitored during storage, the development of rapid monitoring tools suitable for assessing nutritional characteristics arises as a pertinent issue. In this study, cowpea (Vigna unguiculata L.) pods, both fresh and after 6 and 9 months of freezing at -18 °C, were evaluated by high-performance liquid chromatography for their content of protein as well as of essential and nonessential amino acids, while their Fourier transform infrared spectra in the mid infrared (MIR) and near infrared (NIR) ranges were concomitantly registered to assess the feasibility of this approach for the traceability of these frozen matrices.

RESULTS

For the NIR interval, the application of the 1st derivative to the spectral data retrieved the best results, while for lower concentrations the application of the Savitzky-Golay algorithm was indispensable to achieve quantification models for the amino acids. MIR is also suitable for this purpose, though being unable to quantify amino acids with concentrations below 0.07 mmol g^-1 dry weight, irrespective of the data treatment used.

CONCLUSIONS

The spectroscopic approach constitutes a methodology suitable for monitoring the impact of freezing on the nutritional properties of cowpea pods, allowing accurate quantification of the protein and amino acid contents, while NIR displayed better performance. © 2017 Society of Chemical Industry.

Cowpea (Vigna unguiculata L. Walp), a renewed multipurpose crop for a more sustainable agri-food system: nutritional advantages and constraints

The growing awareness of the relevance of food composition for human health has increased the interest of the inclusion of high proportions of fruits and vegetables in diets. To reach the objective of more balanced diets, an increased consumption of legumes, which constitutes a sustainable source of essential nutrients, particularly low-cost protein, is of special relevance. However, the consumption of legumes also entails some constraints that need to be addressed to avoid a deleterious impact on consumers' wellbeing and health. The value of legumes as a source of nutrients depends on a plethora of factors, including genetic characteristics, agro-climatic conditions, and postharvest management that modulate the dietary effect of edible seeds and vegetative material. Thus, more comprehensive information regarding composition, especially their nutritional and anti-nutritional compounds, digestibility, and alternative processing procedures is essential. These were the challenges to write this review, which focusses on the nutritional and anti-nutritional composition of Vigna unguiculata L. Walp, an emerging crop all over the world intended to provide a rational support for the development of valuable foods and feeds of increased commercial value. © 2016 Society of Chemical Industry.

Individualistic impact of unit operations of production, at household level, on some antinutritional factors in selected cowpea-based food products

The individualistic effect of unit operations of production, at household level, on some antinutritional factors in selected cowpea-based food products (moin-moin, akara, and gbegiri) was investigated. Four cowpea types (IT93K-452-1, IT95K-499s-35, IT97K-568-18, and market sample) were used for the study, whereas the three traditional food products were produced from each of the cowpea types, respectively. The results revealed that every unit operation involved in the production of moin-moin, akara or gbegiri contributed to the overall reduction of trypsin inhibitor activity (TIA), phytic acid (PA), and tannin; though at varying degrees. In the production of moin-moin, the major contributions to the overall reduction in TIA were from steaming (64.2-72.0%), second-stage soaking (9.7-11.9%), and dehulling (9.4-10.2%). The contributions to the overall reduction in PA were from dehulling (34.0-40.4%), preliminary soaking (15.4-21.0%), and steaming (7.8-14.0%), whereas that of tannin were from dehulling (39.7-47.6%), steaming (19.6-24.7%), and preliminary soaking (9.8-15.9%). For akara production, the major contributions to TIA reduction were from deep frying (64.2-72.0%), second-stage soaking (9.7-11.9%), and dehulling (9.4-10.2%). The PA reduction was from dehulling (34.0-40.4%), preliminary soaking (15.4-21.0%), and deep frying (9.6-15.9%), whereas that of tannin reduction was from dehulling (39.7-47.6%), deep frying (20.7-25.3%), and preliminary soaking (9.8-15.9%). In the production of gbegiri, the overall reduction in TIA was contributed from pressure cooking (79.0-84.8%), preliminary soaking (5.8-11.3%), and dehulling (9.4-10.2%). The reduction in PA was contributed by dehulling (34.0-40.4%), pressure cooking (24.7-35.0%), and preliminary soaking (15.4-21.0%), whereas the overall reduction in tannin content was similarly contributed by dehulling (39.7-47.6%), pressure cooking (29.8-34.4%), and preliminary soaking (9.8-15.9%).

Nutritive Evaluation of the Bambara Groundnut Ci12 Landrace [Vigna subterranea (L.) Verdc. (Fabaceae)] Produced in Côte d'Ivoire

The nutritional evaluation of the Bambara groundnut Ci12 landrace (Vigna subterranea (L.) Verdc.) seeds produced in Côte d'Ivoire shows a 19% content of protein, containing all the essential amino acids with tryptophan as the limiting amino acid, a total dietary fiber level of 10%, with a low soluble fraction content, and a fat content of 1.4%, with a high proportion of total unsaturated fatty acids (61%) of which 36% were n-6 fatty acids. This legume contains phosphorus, as the major mineral, followed by magnesium and calcium, and trace elements (iron, copper and zinc). It is characterized by the same amount of α-tocopherol and antioxidant capacity as common legumes. The high concentration of essential amino acids, n-6 fatty acids and minerals, mainly Fe, in the Ci12 landrace of Bambara groundnut indicates that this local legume has the potentiality to improve the nutritional status in Côte d'Ivoire and it could be regarded as a nutrient dense food.

Effects of cooking methods on the iron and zinc contents in cowpea (Vigna unguiculata) to combat nutritional deficiencies in Brazil

Background

Because iron deficiency anemia is prevalent in developing countries, determining the levels of iron and zinc in beans, the second most consumed staple food in Brazil, is essential, especially for the low-income people who experience a deficiency of these minerals in their diet.

Objectives

This study aimed to evaluate the effect of cooking methods by measuring the iron and zinc contents in cowpea cultivars before and after soaking to determine the retention of these minerals.

Methods

The samples were cooked in both regular pans and pressure cookers with and without previous soaking. Mineral analyses were carried out by Spectrometry of Inductively Coupled Plasma (ICP).

Results

The results showed high contents of iron and zinc in raw samples as well as in cooked ones, with the use of regular pan resulting in greater percentage of iron retention and the use of pressure cooker ensuring higher retention of zinc.

Conclusions

The best retention of iron was found in the BRS Aracê cultivar prepared in a regular pan with previous soaking. This cultivar may be indicated for cultivation and human consumption. The best retention of zinc was found for the BRS Tumucumaque cultivar prepared in a pressure cooker without previous soaking.