No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Influence of infrared heating processing technology on the cooking characteristics and functionality of African legumes: a review
Abstract
African legumes are an important protein source in the human diet. However, a long and often extended cooking process has been identified as a major challenge in the consumption and utilisation of these legumes. The application of infrared heating as a method of shortening the cooking-time of African legume seeds and flour, by increasing their water absorption rates and pasting viscosity is emphasised in literature. Structural changes caused by infrared heating of moisture-conditioned African legumes include microstructural, molecular and interaction of the biomolecules in the seeds. However, to the best of the authors’ our knowledge, no overview on elucidated mechanisms surrounding the microstructural and molecular changes of infrared heated African legumes has been done. The authors’ therefore, present current knowledge of these mechanisms including certain highlighted factors such as seed sizes, moisture, surface temperature and time, affecting the efficacy of the application of infrared heating to African legumes. In conclusion, infrared heating is a promising technology that provides a potential solution to the consumption and utilisation challenges of African legumes and flour from these legumes, to enhance their consumption in the food industry.
... Infrared heating is an emerging technology that enables very high temperatures to be reached in a short time, leading to increased water absorption during soaking and cooking, reduced cooking time, and improved sensory qualities including color, flavor, and texture. It can also produce instant flours with modified functionality and enhanced fat absorption capacity [112]. Further studies and investigations are needed to assess the consequences and mechanisms through which infrared heating may affect the nutritional properties of legumes [112]. ...
... It can also produce instant flours with modified functionality and enhanced fat absorption capacity [112]. Further studies and investigations are needed to assess the consequences and mechanisms through which infrared heating may affect the nutritional properties of legumes [112]. ...
... Extrusion technology is an important technique that can be employed for the production of various foods, such as crispy snacks (bars, galettes), creamy puffs, breakfast cereals, instant soups and meat substitutes [112]. In recent times, the prospect of incorporating legumes into cereal-based products through the application of extrusion technology has been explored. ...
Legumes are nutrient-dense crops with health-promoting benefits. However, several barriers are associated with their consumption. Emerging issues including food neophobic tendencies or taboos, unclear dietary guidelines on legume consumption, health concerns, and socio-economic reasons, as well as long cooking procedures, adversely affect legume consumption frequency. Pre-treatment methods, including soaking, sprouting, and pulse electric field technology, are effective in reducing the alpha-oligosaccharides and other anti-nutritional factors, eventually lowering cooking time for legumes. Extrusion technology used for innovative development of legume-enriched products, including snacks, breakfast cereals and puffs, baking and pasta, represents a strategic way to promote legume consumption. Culinary skills such as legume salads, legume sprouts, stews, soups, hummus, and the development of homemade cake recipes using legume flour could represent effective ways to promote legume consumption. This review aims to highlight the nutritional and health effects associated with legume consumption, and strategies to improve their digestibility and nutritional profile. Additionally, proper educational and culinary approaches aimed to improve legumes intake are discussed.
... Therefore, several thermal techniques (such as cooking, autoclaving, microwave heating, irradiation, germination, fermentation, extrusion, and drying) used during food processing could be optimized to improve the quality of plant proteins (2). Also, they can be isolated from sustainable and cheap sources such as plant-derived wastes from agriculture and by-products of crop and oil industries, which can also regulate food waste reduction (2,7,18). ...
... The modification approaches for plant-based proteins help them to make multifunctional food products. The modification of proteins can be classified into physical (18,62,(69)(70)(71)(72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82), chemical (125)(126)(127)(128)(129)(130), biological (131,132), and other novel methods (133)(134)(135)(136)(137) as briefly described in Tables 1-3. The physical modification approaches include heat treatment (such as conventional thermal treatment, ohmic heating, microwave heating, radio frequency treatment, infrared irradiation), gamma irradiation, electron beam irradiation, ultraviolet radiation, pulsed-electric field, high-pressure treatment (such as high hydrostatic pressure, dynamic high-pressure fluidization), sonication, extrusion, ball mill treatment, cold atmospheric plasma processing, and ultrafiltration. ...
... These compounds are produced in plants having various biological properties, such as they protect the plants and seeds from insects, fungus, viruses, and other microbes. Therefore, some of the modification approaches discussed have been used to reduce or eliminate the adverse effects of antinutrients (18). Furthermore, some plant-based proteins have challenges in food applications due to their bitter taste, which can be masked by various modulation techniques. ...
Proteins are essential components of the human diet. Dietary proteins could be derived from animals and plants. Animal protein, although higher in demand, is generally considered less environmentally sustainable. Therefore, a gradual transition from animal- to plant-based protein food may be desirable to maintain environmental stability, ethical reasons, food affordability, greater food safety, fulfilling higher consumer demand, and combating of protein-energy malnutrition. Due to these reasons, plant-based proteins are steadily gaining popularity, and this upward trend is expected to continue for the next few decades. Plant proteins are a good source of many essential amino acids, vital macronutrients, and are sufficient to achieve complete protein nutrition. The main goal of this review is to provide an overview of plant-based protein that helps sustain a better life for humans and the nutritional quality of plant proteins. Therefore, the present review comprehensively explores the nutritional quality of the plant proteins, their cost-effective extraction and processing technologies, impacts on nutrition, different food wastes as an alternative source of plant protein, and their environmental impact. Furthermore, it focuses on the emerging technologies for improving plant proteins' bioavailability, digestibility, and organoleptic properties, and highlights the aforementioned technological challenges for future research work.
... Infrared heating, also known as micronization, is an emerging technology being used in food processing with limited applications in pulse processing (Ogundele and Kayitesi, 2019). It is based on the use of electromagnetic radiation with frequencies operating between the visible (0.38-0.78 µm) and microwaves (1-1,000 mm). ...
... The use of infrared heating has many benefits over conventional heating under similar conditions. This includes efficient heating with temperatures between 750 and 930 • C, shorter cooking time, more homogenous heating, lower energy cost, and minimal loss in food quality (Rastogi, 2012;Ogundele and Kayitesi, 2019). However, infrared heating has low penetration power and could cause swelling and fracture in pulses when subjected to longer heating times (Krishnamurthy et al., 2008). ...
... For bulk food products, it is recommended to use infrared heating in combination with techniques such as dehulling and microwave heating to ensure penetration of heat into the food (Krishnamurthy et al., 2008). The efficacy of infrared heating is reliant on parameters such as heating duration, surface temperature, moisture content, and geometry of pulse seeds or products (Ogundele and Kayitesi, 2019). ...
Diversification of plant-based food sources is necessary to improve global food and nutritional security. Pulses have enormous nutritional and health benefits in preventing malnutrition and chronic diseases while contributing positively to reducing environmental footprint. Pulses are rich in diverse nutritional and non-nutritional constituents which can be classified as bioactive compounds due to their biological effect. These bioactive compounds include but are not limited to proteins, dietary fibres, resistant starch, polyphenols, saponins, lectins, phytic acids, and enzyme inhibitors. While these compounds are of importance in ensuring food and nutritional security, some of the bioactive constituents have ambivalent properties. These properties include having antioxidant, anti-hypertensive and prebiotic effects. Others have a deleterious effect of decreasing the digestibility and/or bioavailability of essential nutrients and are therefore termed antinutritional factors/compounds. Various processing techniques exist to reduce the content of antinutritional factors found in pulses. Traditional processing of pulses comprises soaking, dehulling, milling, germination, fermentation, and boiling, while examples of emerging processing techniques include microwaving, extrusion, and micronization. These processing techniques can be tailored to purpose and pulse type to achieve desired results. Herein, the nutritional qualities and properties of bioactive compounds found in pulses in meeting the sustainable development goals are presented. It also discusses the effect of processing techniques on the nutritional and non-nutritional constituents in pulses as well as the health and environmental benefits of pulse-diet consumption. Major challenges linked to pulses that could limit their potential of being ideal crops in meeting the sustainable development goal 2 agenda are highlighted.
... The order-disorder phase changes the molecular structure of the starch and thereby alters the granules of starch (Sciarini et al. 2015). Micronising starch by IR heating is a short-time processing method involving exposure of moisture-conditioned grain to IR in the wavelength range between 1.8 and 3.4 µm (Ogundele and Kayitesi 2019). The moisture-conditioned grain absorbs the radiation, which causes intermolecular friction and vibration amongst the water molecules and other substances, leading to water vapor pressure rise and heat generation in the product (Ogundele, Minnaar, and Emmambux 2017). ...
... During IR treatment, the granular complexity of the product plays a major role in starch digestibility. However, an increase in starch digestibility has been observed in IR-treated legumes (Ogundele and Kayitesi 2019). ...
Infrared (IR) radiation has been used in food processing applications for its unique high heating efficiency. There is a great need to address the radiation absorption and heating effect during the application of IR in the processing of foods. The radiation wavelength determines the nature of the processing, and it is mainly affected by the type of emitter, operating temperature, and the power supplied. The penetration depth of the IR on food material plays a critical role in the heating level along with the optical characteristics of the IR and food product. The IR radiations cause a significant change in the food components like starch, protein, fats and enzymes. The facility to generate wavelength-specific radiation output can hold the potential of momentously increasing the efficiency of IR heating operations. IR heating is gaining importance in 3D and 4D printing systems, and the application of artificial intelligence in IR processing is being explored. This state-of-art review gives a detailed view of the different emitters of IR and mainly emphasizes the behavior and changes of major food components during IR treatment. The penetration depth of IR, optical characteristics and selective spectral heating based on the target product are discussed.
... Infrared (IR) radiation is generally conveyed as an electromagnetic wave, transforming its energy into heat. The heat generated, possibly due to water molecule absorption of the IR energy, endorses less or nearly no damage to the food quality (Bingol et al. 2014;Ogundele and Kayitesi 2019). Heat is transferred through radiative and conduction mechanisms in IR heating. ...
... However, an inverse relationship between IR intensity and distance, as shown in Figure 5. Atungulu (2018a) stated that increasing radiation distance reduces radiation intensity because of radiation scattering. Nevertheless, an increase in intensity with increasing input power, where water molecules absorb IR rays primarily (Ogundele and Kayitesi 2019). Therefore, the interactions amongst these parameters could impact the texture and rheology of food. ...
Infrared (IR) radiation is part of an electromagnetic spectrum between the ultraviolet and microwave regions. IR radiation impacts the surface of the food, generating heat that can be used as an efficient drying technique. Apart from drying, IR heating is an emerging food processing technology with applications in baking, roasting, microbial inactivation, insect control, extraction for antioxidant recovery, peeling, and blanching. Physicochemical properties such as texture, color, hardness, total phenols, and antioxidants capability of foods are essential quality attributes that affect the food quality. In this regard, the main objective of this review study was to highlight and discuss the effects of IR heating on food quality to expand its food applications and commercial adoption. The fundamental mechanisms, type of emitters, and IR processing parameters are discussed in this review to explore their impacts on food quality. Infrared heating has been shown that the appropriate operating conditions (distance, exposure time, IR power, and temperature) with high heat transfer, thus leading to a shorter drying time. Besides, IR heating used in food processing to improve food-surface color and flavor, it also enhances hardness, firmness, shrinkage, crispiness, and viscosity. Meanwhile, antioxidant activity is enhanced, and some nutrients are retained.
... Cowpea is mostly utilized as cooked whole seeds often achieved after boiling for up to 2 h, resulting in extensive energy consumption and long food preparation times [7]. Owing to this, attempts are being made to reduce the time it takes to cook leguminous seeds by employing traditional methods, such as soaking in salted water using Kawe (natural rock salt) and the application of hydrothermal process including microwaving annealing and infrared heating [8]. ...
... Infrared radiation heating is a heat pre-treatment process that uses electromagnetic radiation in the infrared region within the wavelength of about 3 to 1000 µm [8,9]. Over the last decade, attempts have been undertaken to rapidly heat moisture-conditioned legumes, using a table-top infrared heater with varied processing parameters of moisture (30-41%), infrared heating temperature (130-170 • C), and time (3-8 min) of bambara groundnut [10] and cowpea [11] seeds, with results suggesting an improvement in water hydration during soaking and cooking as well as a reduction in cooking time. ...
The infrared heating of preconditioned cowpea improves its utilization and potential application in food systems. This study investigated the effect of optimizing preconditioning and infrared heating parameters of temperature and time on cooking characteristics of precooked cowpeas using response surface methodology (RSM). The moisture level (32–57%), infrared heating temperature (114–185 °C), and time of processing the seeds (2–18 min) were optimized using a randomized central composite design to achieve optimal characteristics for bulk density and water absorption. A second-order polynomial regression model was fitted to the obtained data, and the fitted model was used to compute the multi-response optimum processing conditions, which were the moisture of 45%, the heating temperature of 185 °C, and time of 5 min. Precooked cowpea seeds from optimized conditions had a 19% increase in pectin solubility. The total phenolic and total flavonoid contents were significantly reduced through complexation of the seeds’ phenolic compounds with other macromolecules but nonetheless exhibited antioxidant properties capable of scavenging free radicals. There was also a significant reduction in phytate and oxalates by 24% and 42%, respectively, which was due to the heat causing the inactivation of these antinutrients. The obtained optimized conditions are adequate in the production of precooked cowpea seeds with improved quality.
... Of late application of micronization in the food industry is gaining unprecedented attention due to several advantages such as effectiveness, safety, cleanliness and short processing time (Pathiratne et al., 2015). In recent years, positive impacts of micronization on the functionality of grain flours have been reported on desi chickpeas and hull-less barley flours (Bai et al., 2018), lentil flour (Pathiratne et al., 2015) and African leguminous flours (Ogundele et al., 2019). However, to our knowledge, no study has hitherto focused on the potential effect of this technique on functional attributes of protein extracted from by-products. ...
... There was no major difference between the native and micronized proteins. The literature on the impact of infrared heating on the microstructure of proteins is very limited; however, few studies documented certain microstructural changes in biomolecules of grain flours for the same treatment (Ogundele et al., 2019). Sample US 5 contained relatively smaller particles when compared to the native protein (Fig. 5), suggesting that the shorter period of sonication might break protein bodies into small particles. ...
The black gram mill by-product is a valuable protein-rich source that is generally discarded. Therefore, this study was conducted to extract the protein from this underutilized source and further improve its functionality by using ultrasound and micronization techniques. Protein micronized at 110 °C had maximum water absorption (from 2.79 to 4.83 g/g) and emulsifying activity (from 9.94 to 38.32 m²/g). Ultrasonicated proteins for 10 min and 30 min exhibited the highest oil absorption (3.18–3.66 g/g) and foaming capacity (53.7–91.25%), respectively. When compared to ultrasonication, micronization particularly at 150 °C, was very effective in improving zeta potential (−18.7 to −24.95 mV). Thermal properties suggested structural changes, particularly in ultrasonicated proteins. FT-IR spectra showed no marked alteration in the secondary structure, while the electrophoretic pattern showed slight reduction in the intensity of the major band in modified proteins. The findings indicated that these techniques substantially enhanced the functionality of by-product protein, thus might increase its utilization in various food systems.
... Методика IR -нагрева предполагает минимизацию продолжительности воздействия электромагнитного излучения на продукты питания с использованием длин волн от 1,8 до 3,4 мкм (Ogundele & Kayitesi, 2019). Эта форма нагрева приводит к тому, что ядро сначала высыхает изнутри к внешней периферии посредством конвекции и излучения, обеспечивая более высокую скорость теплопередачи. ...
... The IR heating technique involves minimizing the duration of food exposure to electromagnetic radiation using wavelengths of 1.8 to 3.4 µm (Ogundele & Kayitesi, 2019). This form of heating causes the kernel to dry initially from the interior to the outer periphery via convection and radiation, producing a higher rate of heat transfer. ...
Emerging nonthermal and thermal food processing technologies are a better alternative to conventional thermal processing techniques because they offer high‐quality, minimally processed food. Texture is important in the food industry because it encompasses several product attributes and plays a vital role in consumer acceptance. Therefore, it is imperative to analyze the extent to which these technologies influence the textural attributes of food grains. Physical forces produced by cavitation are attributed to ultrasound treatment‐induced changes in the conformational and structural properties of food proteins. Pulsed electric field treatment causes polarization of starch granules, damaging the dense outer layer of starch granules and decreasing the mechanical strength of starch. Prolonged radio frequency heating results in the denaturation of proteins and gelatinization of starch, thus reducing binding tendency during cooking. Microwave energy induces rapid removal of water from the product surface, resulting in lower bulk density, low shrinkage, and a porous structure. However, evaluating the influence of these techniques on food grain texture is difficult owing to differences in their primary operation mode, operating conditions, and equipment design. To maximize the advantages of nonthermal and thermal technologies, in‐depth research should be conducted on their effects on the textural properties of different food grains while ensuring the selection of appropriate operating conditions for each food grain type. This article summarizes all recent developments in these emerging processing technologies for food grains, discusses their potential applications and drawbacks, and presents prospects for future developments in food texture enhancement.
... This thermal energy is generated by the molecular vibrations induced by the infrared radiation. Moreover, some solvent characteristics are modified during IR, such as surface tension and viscosity, increasing the likelihood of solubilization and the recovery of more compounds [49,82,83]. ...
Olive leaves are naturally generated as a by-product during olive harvesting and olive oil production. Usually discarded with no specific use, they are a valuable source of bioactive compounds that should not be overlooked. Their valorization must therefore be achieved through the recovery of their polyphenols using an ecological strategy. Conventional extraction is commonly known as an energy- and solvent-consuming process, whereas emerging and innovative extraction technologies, such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pulsed-electric-field-assisted extraction (PEF), high-voltage-electric-discharge-assisted extraction (HVED), supercritical fluid extraction (SFE), infrared-assisted extraction (IAE), and “Intensification of Vaporization by Decompression to the Vacuum” (IVDV), are considered more sustainable and environmentally friendly. The aim of this review is to provide a comprehensive and updated overview of the valorization of olive leaves through both pretreatment and extraction techniques via an analysis of the recovered polyphenols and their potential applications.
... Infrared heating (micronisation) can also result in reduction in cooking time of Bambara groundnut (Ogundele and Emmambux, 2018), which not only helps to save energy and water, but also has knock-on positive impacts on the retention of nutrients. This instant heating process, which causes starch gelatinisation and protein denaturation, could enhance the utilisation of Bambara groundnut seeds and flour for production of a diverse range of convenience products such as partially-cooked seeds or instant flour (Ogundele and Kayitesi, 2019). ...
Bambara groundnut (Vigna subterranea (L.) Verdc.) is a potential crop for future sustainable agri-food systems. However, utilisation of the crop is constrained by several factors, one of which is the hard-to-cook (HTC) phenomenon. The HTC seeds do not soften sufficiently after prolonged cooking time, thus demanding more energy for preparation. This, in turn, reduces the economic value and consumers acceptance of the pulse. The objective of this project was to explore the HTC traits in Bambara groundnut through the evaluation of physicochemical, microstructural, and technological properties to provide a basis to improve the processing efficiency and utilisation of the nutrient-dense pulse. A screening study was first conducted to assess the variability and relationship between physical, microstructural, hydration and cooking characteristics among 12 Bambara groundnut genotypes. The physical traits of the seeds, which were characterised in terms of geometric, gravimetric, and seed coat properties, varied among genotypes. Thick seed coat (95.29-133.19 μm) and palisade layer (70.62-103.03 μm), compact cotyledon cells, narrow hilar groove, small tracheid bar, and occluded micropyle were among the factors contributing to the poor hydration behaviour of Bambara groundnut. During the soaking process, the seed coat, which exhibited moisture-dependent permeability, was the primary barrier to initial water uptake among the dry seeds. A sigmoidal model was applied to describe the hydration kinetics of the seeds. Three hydration parameters were subsequently estimated: (1) equilibrium moisture content (94.5-135.2 %), (2) hydration rate (0.095-0.272 h-1), and (3) time to achieve half saturation (9.6-24.8 h). The cooking times (CTs) also showed genotypic variation, ranging from 70-208 mins and 38-120 mins for partially and fully hydrated seeds, respectively. The CT of fully hydrated seeds was not correlated (p>0.05) with any of the physical, microstructural and hydration kinetics parameters. It was, however, significantly (p<0.05) correlated with leaching losses during soaking, supporting the cell membrane deterioration hypothesis. The objective of the second stage of this study was to examine the differences in the characteristics of starch, protein, and cell wall materials between easy-to-cook (ETC) and hard-to-cook (HTC) genotypes. Two ETC genotypes (C_KARO and R_SONG; CT: 38-43 min) and two HTC genotypes (B_IPBB and N_ANAM; CT: 80-120 min) were selected for this study. Genotypic differences in cooking time could not be attributed to protein content and solubility. Additionally, the results of Fourier transform infrared spectroscopy indicated that there was no association between ease of cooking and molecular order of starch, secondary structure of protein, and molecular structure of cell wall materials. However, using a differential scanning calorimetry, a greater (p<0.05) thermal stability was observed among the HTC genotypes, as reflected by a higher thermal transition temperature and enthalpy of change. The HTC genotypes also exhibited a higher content of chelator-soluble pectin (p<0.05) and a lower content of water-soluble pectin (p<0.01) compared to the ETC genotypes, indicating the role of pectin solubility in strengthening intercellular adhesion and delayed cell separation during cooking. In the final study, the response surface methodology was applied to identify the optimal soaking solution for Bambara groundnut genotype C_NAV4 to maximise the hydration capacity and cookability of seeds while minimising colour changes of the cooked seeds. Consequently, a soaking solution containing 0.25% NaHCO3 + 0.14% Na2CO3 was selected. A comparative study was then conducted to assess the impact of salt solution on the hydration and cooking behaviour of the seed. The most notable effects arising from the presence of alkaline salt in the soaking solution were: (1) an improved hydration behaviour during soaking, as evidenced by a shorter lag time (τ = 8.1 h) and a faster hydration rate (k = 0.211 h-1) than that of distilled water-soaked seeds (τ = 10.9 h and k = 0.181 h-1, respectively), (2) a greater leaching loss throughout soaking and cooking processes, (3) a significant (p<0.05) decrease in the level of chelator-soluble pectin, and (4) a 2.5-fold increase in the rate constant of cooking. These results indicate that the salt solution was effective in improving the hydration rate and shortening the cooking time of Bambara groundnut. The microstructural changes at various stages of cooking provided evidence for an association between cotyledon cell separation and texture softening of seeds.
... However, in Figure 8b, cracks are visible due to IR heating and this facilitates peel loosening. Rapid pressure build-up and moisture vaporization from the inner surface has led to the rupture of the tunics and the creation of fissures on the surface of the skin during IR heating (Ogundele & Kayitesi, 2019). In Figure 8c, the untreated shallot bulb image shows that the cell structures are intact, and it is not subjected to damage. ...
Different wavelength emitting infrared (IR) lamps (transparent quartz tungsten (TQT), ruby‐coated quartz tungsten (RCQT), and ceramic) were used for dry peeling and evaluating the spectral characteristics of emitted radiations. The maximum temperatures for ceramic, RCQT, and TQT were 560, 662, and 861°C, respectively. The peak wavelength determined by Wien's law was between 3.37 and 21.47 µm. Comparatively, longer wavelength was emitted by ceramic lamp. The spectral emissive power determined by Stefan Boltzmann's law was 1.14–37.49 kW m⁻² using the IR emitters at different power levels. The radiant efficiency was higher for the ceramic lamp. The peak wavelength and emissive power had a major influence on the peeling performance and quality during IR peeling. The optimized parameters for IR dry peeling of shallots are 60 mm distance between lamp and product, 59.74% IR power level, 15 min of heating time using the ceramic (peak wavelength 8.16 µm) lamp.
Practical Application: Infrared dry peeling of shallots is a sustainable alternative to traditional peeling methods that leaves adverse environmental footprints. Spectral characteristics of the infrared lamp can be used to determine the suitable emitter for the dry‐peeling operation. It is necessary to check the wavelength emitted by the source for designing the IR system based on the food product and application. This study will be helpful in food processing industries to use an effective infrared lamp that can efficiently peel the agricultural product and sustainably maintain quality.
... In the food industry, sensory attributes and shelf-life are enhanced by altering the food's chemical bonds using various irradiation processes like radappertization, radicidation, and radurization (Sivasankar, 2014). Ogundele and Kayitesi (2019) used an infrared emitter, which generated 1.3 μm-3.0 μm wavelength. This energy was absorbed by moisture-conditioned foods and the subsequent heat transfer mechanism resulted in changes in the biomolecules and their microstructures, which eventually modified the food. ...
Background
Coffee (Coffea arabica) and tea (Camellia sinensis) are beverages consumed widely across the globe. Flavor enhancement of beverages is the prime interest for consumers and industry, but it is still a major challenge for researchers.
Objectives
In this work, we aimed to enhance the sensory characteristics and lower the caffeine content of tea and coffee by applying 2–6 μm mid-infrared wavelengths emitted through our recently invented Mid-Infrared Generating Atomizer (MIRGA) without creating any adverse effects.
Methodology
Two methods were followed: Direct MIRGA spraying over the packaged coffee or tea powder packets, and direct MIRGA spraying over the liquid coffee or tea. Controls were maintained in both methods. The treated samples were subjected to organoleptic tests by an expert panel and consumers.
Results
This study is supported by comprehensive field trials, including sensory attributes evaluation and laboratory analyses. In coffee, spraying resulted in 8% decaffeination and increase in theobromine and theophylline by 40% and 10–20%, respectively. In tea, caffeine and theobromine increased by 20–25% and 30%, respectively in addition to a 0.6–1.2% increase in thearubigins. A 20–30% lower amount of sprayed coffee or tea powder was required to prepare beverages with regular sensory characteristics. We have proven that the MIRGA technology applied to the products reduced the caffeine content in coffee, rendered them safe to consume, improved the taste and flavor, and induced health benefits. In addition, as the MIRGA platform contributed toward improving the product characteristics, it can also positively impact their price and affordability.
Conclusion
Applications of MIRGA technique and its benefits can be potentially scaled up and utilized for a variety of products used in daily life.
... Infrared heating, also known as micronization, is based on the absorption of far infrared (FIR) energy at the wavelength above 2.5 mm (Ogundele and Kayitesi, 2019). In relation to pulse processing, it has been shown to reduce the trypsin inhibitor activity of peas by up to 94% . ...
Pulse proteins stand as promising food ingredients with the potential to sustainably contribute to the nutritional needs of a growing world population. While benefiting from enhanced functionality and tailored biological activity towards health promotion, safety- and sensory-related issues may challenge the overall acceptability of pulse-based products. This chapter reviews potential food applications of pulse proteins, as well as protein extraction methods. Overall, safer and more sustainable products with enhanced functionality and bioactivity can be achieved when combining traditional and innovative processes. However, further research efforts should be directed towards production cost-effectiveness on an industrial scale and consumer acceptance to fully enable the game-changing market potential of pulse proteins.
... The benefits of IR heating over conventional heating include efficient heating with temperatures at 750-930 °C, shorter cooking time, more homogenous heating, lower energy cost and minimal loss in food quality. For bulk food products, the recommendation is combination with other techniques, such as dehulling and microwave heating to ensure penetration of heat into the food ( Ogundele & Kayitesi, 2019 ). ...
Legumes have immense health benefits to humans and animals, while substantially contributing to soil amelioration. However since they contain several antinutients, customarily legumes go through several processes before they are used as plated items or as another food ingredient. The contents of antinutrients in legumes have been reduced by applying various traditional and avant-garde processing methods. The traditional ones, like dehulling, soaking, boiling, pressure cooking, sprouting and fermentation help in the reduction of certain antinutrients, such as α-galactosides, phytic acid, enzyme inhibitors, lathyrogens, lectins, saponins and tannins. There also has been contemporary research which indicates the effectiveness of some recent innovative processes, such as dielectric heating, extrusion, γ-irradiation, ultrasound and high hydrostatic pressure in reducing antinutrients. This review is intended to assess the different types of antinutrients in legumes, their structure-function relations and the various processing methods which are going through as well as which have potentiality to be deployed in reducing or eliminating the antinutrients. Moreover, since these technological processes need to be optimised for more effectiveness, minimisation of antinutrients by using response surface methodology has also been highlighted. These processing techniques can be tailored or optimised to achieve targeted results.
... The results show a significant impact of micronization on the seed structure, as the stress values were ten times lower than those of the control samples. Infrared radiation treatment was also used in the case of African legumes [62]. As reported by the study, water is absorbed faster, which resulted in better viscosity of the pastes obtained. ...
In this study, a number of the most common methods used in assessing the efficiency of soybean heat treatment were compared. All the methods proved to be useful in assessing the efficiency of heating soybean seeds and soybean products. However, considering the sensitivity, precision, time consumed, and the effectiveness of determination of the characteristics of the samples, the use of the bromocresol purple index (BCPI) appears to be justified. The BCPI method turned out to be universal, allowing distinguishing unheated (BCPIBSM < 70 mg·g⁻¹), under-heated (70 mg·g⁻¹ < BCPI BSM < 130 mg·g⁻¹), properly heated (BCPI BSM = 130–140 mg·g⁻¹), and over-heated samples (BCPI BSM > 140 mg·g⁻¹).
... Moreover, IR possesses higher heating rates, uniform heating, rapid heating and higher ability to maintain the food quality and safety. It is reported that the exposure of proteins to IR heating denatures them or makes them more susceptible to denaturation and aggregation due to the unfolding of their molecules (Ogundele & Kayitesi, 2019). The submission of African legumes to IR heating resulted in an increase in their digestibility and decrease in the amount of their anti-nutritional factors such as α-galactosides, protease 21 inhibitors, tannins and/or lectins (Nti, 2009). ...
Plant-based proteins have recently attracted particular interest owing to their sustainable origins, economical costs and health benefits compared to animal-based counterparts. However, most of them have limited applications due to their inferior functionality, which is the consequence of poor-aqueous solubility, complexity and sensitivity to environmental stress conditions such as pH, salt and temperature. Additionally, plant proteins are often embedded in hemicellulose, lignin and other poorly digestible polysaccharides, which further reduce their bioavailability. Therefore, the modulation of plant proteins to improve their technological and industrial applications, and make them more accessible in general, is highly sought after.
The modification of plant proteins by altering their physicochemical properties provides the possibility to improve and diversify their techno-functionality and biological activities as well as addressing their limitations. The selection of protein modification method should be done carefully from the final application view especially in food products since it can influence the protein functional, nutritional and organoleptic properties. Therefore, discussing different modification methods with their advantages and disadvantages is particularly timely. This review highlights and discusses the modification methods for plant proteins in order to make their applications in foods more feasible by improving their flavor, nutrition and techno-functional attributes, which will open up new opportunities within different plant-based food products.
... The results show a signi cant impact of micronization on the seed structure, as the stress values were ten times lower than those of the control samples. Infrared radiation treatment was also used in the case of African legumes [60]. As reported by the study, water is absorbed faster, which resulted in better viscosity of the pastes obtained. ...
A number of the most common methods used in assessing the efficiency of soybean heat treatment were compared in this study. All the methods proved to be useful in assessing the efficiency of heating soybean seeds and soybean products. However, considering the sensitivity, precision, time consumed, and the effectiveness of determination of the characteristics of the samples, the use of purple bromocresol index (BCPI) appears to be justified. The BCPI method turned out to be universal, allowing distinguishing unheated (BCPI BSM <70 mg . g ⁻¹ ), under-heated (70 mg . g ⁻¹ <BCPI BSM <130 mg . g ⁻¹ ), properly heated (BCPI BSM = 130-140 mg . g ⁻¹ ), and over-heated samples (BCPI BSM > 140 mg . g ⁻¹ ).
... Infrared heating (micronization) can also result in reduction in cooking time of Bambara groundnut (74), which not only helps to save energy and water but also has knock-on positive impacts on the retention of nutrients. This instant heating process, which causes starch gelatinization and protein denaturation, could enhance the utilization of Bambara groundnut seeds and flour for production of a diverse range of convenience products such as partially cooked seeds or instant flour (75). ...
Rapid population growth, climate change, intensive monoculture farming, and resource depletion are among the challenges that threaten the increasingly vulnerable global agri-food system. Heavy reliance on a few major crops is also linked to a monotonous diet, poor dietary habits, and micronutrient deficiencies, which are often associated with diet-related diseases. Diversification—of both agricultural production systems and diet—is a practical and sustainable approach to address these challenges and to improve global food and nutritional security. This strategy is aligned with the recommendations from the EAT-Lancet report, which highlighted the urgent need for increased consumption of plant-based foods to sustain population and planetary health. Bambara groundnut (Vigna subterranea (L.) Verdc.), an underutilized African legume, has the potential to contribute to improved food and nutrition security, while providing solutions for environmental sustainability and equity in food availability and affordability. This paper discusses the potential role of Bambara groundnut in diversifying agri-food systems and contributing to enhanced dietary and planetary sustainability, with emphasis on areas that span the value chain: from genetics, agroecology, nutrition, processing, and utilization, through to its socioeconomic potential. Bambara groundnut is a sustainable, low-cost source of complex carbohydrates, plant-based protein, unsaturated fatty acids, and essential minerals (magnesium, iron, zinc, and potassium), especially for those living in arid and semi-arid regions. As a legume, Bambara groundnut fixes atmospheric nitrogen to improve soil fertility. It is resilient to adverse environmental conditions and can yield on poor soil. Despite its impressive nutritional and agroecological profile, the potential of Bambara groundnut in improving the global food system is undermined by several factors, including resource limitation, knowledge gap, social stigma, and lack of policy incentives. Multiple research efforts to address these hurdles have led to a more promising outlook for Bambara groundnut; however, there is an urgent need to continue research to realize its full potential.
... IR radiation is one of the electromagnetic spectra and the wavelength range of IR radiation is between 0.5 and 100 μm . IR heating applications in food processing include food drying (Yao, Fan, & Duan, 2020), inactivation of enzymes (Jeevitha, Hebbar, & Raghavarao, 2016), peeling of fruits and vegetables (Vidyarthi et al., 2019), inactivation of microorganisms (Watson, Kamble, Shanks, Khan, & El Darra, 2020), roasting (Bagheri, Kashaninejad, Ziaiifar, & Aalami, 2019), cooking (Ogundele & Kayitesi, 2019), and blanching (Wu, Guo, Wang, Pan, & Ma, 2018). IR possesses a lot of advantages compared to conventional thermal heating such as uniform heating, deep penetration, significant energy saving, less heating time, and decreased rate of food degradation thereby improving the quality of food preservation (Krishnamurthy et al., 2008). ...
Infrared irradiation is an alternative method for the thermal processing of foods. Lime is one of the citrus fruits and considered beneficial for human health. Dried lime juice is common in the Middle Eastern region and alternatives are desired to the conventional resistance heating method for the elimination of undesirable microorganisms. A batch infrared extraction pasteurizer (BIREP) was developed to test both infrared and conventional heating methods. Dried lime juice was treated in the BIREP using combinations of temperature (60, 75, and 90°C) and power output (350, 525, and 700 W) from infrared bulbs using a central composite design. Samples were subsequently analyzed for dependent variables of ascorbic acid content, total phenolic content, antioxidant activity, pectin methylesterase, hydroxymethyl, total plate counts, lightness, redness, and yellowness. Each combination of temperature and power was also quantified for specific infrared energy consumption, energy efficiency, and productivity. BIREP temperature and power settings were optimized for all dependent variables. The resulting optimized settings were used to process another set of dried lime juice samples. These samples were compared to control (untreated) and conventional heating samples. Sensory (appearance, aroma, taste, and overall acceptability) evaluation was conducted by a panel of humans. Infrared processing was superior to conventional processing and equivalent to control samples in all four sensory tests. The results indicated strong potential for infrared processing as a superior alternative to conventional heating for the preservation of dried lime juice. Infrared heating offers a safe alternative to conventional resistance heating that equals or improves the consumer‐desired characteristics compared to fresh dried lime juice and provides a marked improvement over conventional heating. This may allow infrared processed juice to warrant a price premium over conventional thermal processing. Since dried lime producers typically thermally process their juice using the batch method, they can switch to infrared heating to improve the quality of their processed juice and promote the resulting benefits. Cost‐benefit studies would be appropriate for dried lime juice processers to evaluate the conversion of thermal processing to infrared heating to take advantage of the superior product.
... This phenomenon breaks the oil cell walls and releases the oil. It was reported that water molecules absorb infrared energy and convert it into thermal energy (Ogundele & Kayitesi, 2019). Also, it was explained by the researcher that high moisture content foods absorb a large fraction of infrared rays (Vidyarthi et al., 2018). ...
This study proposed a new infrared-based oil extraction technique and investigated the applicability of this method for the recovery of oil from the viscera of common carp (Cyprinus carpio var. communis) at pilot-scales. An optimization attempt was performed to understand the effects of independent process parameters of this novel valorization approach, i.e., input power (130–250 W), temperature (50–70 °C), and the radiation distance (1–30 cm), on oil yield (OY), viscosity, thiobarbituric acid (TBA), free fatty acid (FFA), and peroxide value (PV) using the response surface methodology. The optimal extraction conditions were found to be the input power of 168.3 W, the temperature of 70 °C, and a distance of 6.08 cm. OY, viscosity, TBA, FFA, and PV at these processing conditions are expected to be 23.73%, 3.04 Pa.s, 1.55 mg malonaldehyde/kg oil, 0.675%, and 2.83 meq/kg oil, respectively. Besides, statistical results showed reduced cubic and quadratic models were well-fitted on the experimental data to predict PV and OY, respectively. The proposed valorization technique has a good potential for industrial adaptation considering the simplicity of the technology, ease of process control, and the possibility of enhancing the fish oil quality and quantity.
The increasing prevalence of dairy protein allergies, lactose intolerance, and environmental concerns associated with dairy production have spurred interest in plant-based alternatives. Among these, pulse proteins are gaining recognition as promising ingredients due to their lower production costs, rich nutritional content, functional versatility, and health benefits. This review explores the nutritional, antinutritional, and functional properties of pulse proteins and their application in the development of dairy alternatives. It also examines how different processing techniques impact the characteristics of pulse proteins and assesses the environmental benefits of pulse production. The literature highlights that pulses are an excellent source of protein, particularly lysine, and are also rich in carbohydrates, fiber, and starch, though variations exist depending on the type of pulse. Additionally, pulses are a valuable source of prebiotics, which support gut health. Their functional properties, such as emulsification, solubility, gelation, and water holding capacity, vary significantly depending on the pulse type, composition, processing techniques, and factors like pH. In terms of product applications, researchers have explored developing yogurt, cheese, kefir, and ice cream alternatives using pulses. However, challenges remain in achieving desirable texture properties and sensory characteristics. Various traditional and novel processing techniques have been investigated to ensure microbial safety, mitigate antinutritional factors, and enhance the digestibility of pulse components. Pulse-based dairy alternatives present a sustainable and nutritious option, particularly for individuals with lactose intolerance. Despite their potential, challenges persist in optimizing protein content, refining processing parameters, and addressing scalability for commercial production. Overcoming these obstacles is crucial to advancing the development and market adoption of pulse protein–based dairy alternatives. Future studies should focus on generating robust literature to optimize pulse protein content, refine processing parameters, and develop effective strategies for scaling up production to enable successful commercialization.
Since the world's population has surged in recent decades, the need for sustainable as well as environmentally friendly protein sources is growing. However, there are daunting challenges in utilizing these protein sources in the food industry due to their poor techno-functional properties compared with animal proteins. Numerous procedures have been introduced to improve plant protein functionalities with related pros and cons. Among them, complexation with polysaccharides is considered a safe and effective process for modulating plant proteins' technological and industrial applications. Notwithstanding the nutritional value of soy protein (SP) as a "complete protein," it is a crucial protein commercially because of its rank as the highest-traded plant-based protein worldwide. The current review deals with SP complexation with ionic polysaccharides, including chitosan, alginate, carrageenan, and xanthan gum, and their effects on the physicochemical and techno-functional properties of SP. Accordingly, the structure of SP and the abovementioned polysaccharides have been considered for a better understanding of the possible interactions. Then, the changes in the physicochemical and functional properties of SP and their potential applications in the formulation of plant-based food products have been discussed. Overall, ionic polysaccharides at optimum conditions would improve the functional properties of SP by altering its secondary structure, making it suitable for a wide range of applications in the food industry.
Foods undergo various physical and chemical reactions during cooking. Boiling, steaming, baking, smoking and frying are common traditional cooking techniques. At present, new cooking technologies including ultrasonic-assisted cooking, vacuum low-temperature cooking, vacuum frying, microwave heating, infrared heating, ohmic heating and air frying are widely studied and used. In cooking, lipid oxidation is the main reason for the change in lipid quality. Oxidative decomposition, triglyceride monomer oxidation, hydrolysis, isomerization, cyclization reaction and polymerization occurred in lipid oxidation affect lipids' quality, flavor, digestibility and safety. Meanwhile, lipid oxidation in cooking might cause the decline of lipid digestibility and increase of health risks. Compared with the traditional cooking technology, the new cooking technology that is milder, more uniform and faster can reduce the loss of lipid nutrition and produce a better flavor. In the future, the combination of various cooking technologies is an effective strategy for families to obtain healthier food.
Cowpea is widely grown and consumed in sub-Saharan Africa because of its low cost and high mineral, protein, and other nutritional content. Nonetheless, cooking it takes considerable time, and there have been attempts on techniques for speeding up the cooking process without compromising its nutritious value. Infrared heating has recently been proposed as a viable way of preparing instantized cowpea grains that take a short amount of time to cook while maintaining desired sensory characteristics. Despite this, only a few studies have shown the impact of moisture, temperature, and cooking time on cooking characteristics such as bulk density, water absorption (WABS), and the pectin solubility of infrared heated cowpea precooked using this technology. Artificial neural network was used as a machine learning tool to study the effect of a prediction model on the infrared heating performance and cooking characteristics of precooked cowpea seeds. With R values of 0.987, 0.991, and 0.938 for the bulk density, WABS, and pectin solubility, respectively, the prediction model created in this study utilizing an artificial neural network (a type of machine learning) outperformed the traditional linear, 2-factor interaction, and quadratic models.
Proteins are the principal supplier of nitrogen for growth, repair and maintenance of tissues and vital physiological functions. Plants produce a variety of noxious compounds to protect themselves against the predators like herbivores, insects, pathogens, and microbes as well as to fight against the adverse environmental factors. The noxious compounds, which impact the optimum utilization of food nutrients and reduce their digestion, absorption and metabolic utilization and may generate adverse health effects, are termed as antinutritional factors (ANFs). Depending on their structure and molecular weight, these ANFs of plant foods can limit the utilization of their nutrients and may trigger variable adverse physiological effects in humans. The major ANFs and toxic compounds present in plant foods are protease inhibitors, α-amylase inhibitors, α-galactosides, anti-minerals, phytates, oxalates, tannins, polyphenols, alkaloids, lectins, phytohaemagglutinins (PAH), gossypol, saponins, cyanogenic glycosides, compounds causing favism, lathyrogens, goitrogens, phytoestrogens, lipoxygenases, anti-vitamin factors, uricogenic nucleobases in yeast protein products, toxic proteins, and food allergens etc. Some of these ANFs in plant protein foods can be toxic, some make them unpalatable by adding bitter taste, whereas the others may have adverse effects leading to reduced growth and fitness through nutrient complexation, metabolic inhibition and/or interference with digestion and absorption of nutrients. The safety, nutritional quality, and palatability of plant protein foods can however be improved by a variety of processing techniques. This chapter describes the presence of these ANFs in plant protein food sources, their mechanism of action, processing methods to reduce or eliminate them from plant food sources and showcases their adverse health effects in humans.
Cowpea is widely grown and consumed in sub-Saharan Africa because of its low cost and high mineral, protein, and other nutritional content. Nonetheless, cooking it takes considerable time, and there have been attempts on techniques for speeding up the cooking process without compromising its nutritious value. Infrared heating has recently been proposed as a viable way of preparing instantized cowpea grains that take a short amount of time to cook while maintaining desired sensory characteristics. Despite this, only a few studies have shown the impact of moisture, temperature, and cooking time on cooking characteristics such as bulk density, water absorption (WABS), and the pectin solubility of infrared heated cowpea precooked using this technology. Artificial neural network was used as a machine learning tool to study the effect of a prediction model on the infrared heating performance and cooking characteristics of precooked cowpea seeds. With R values of 0.987, 0.991, and 0.938 for the bulk density, WABS, and pectin solubility, respectively, the prediction model created in this study utilizing an artificial neural network (a type of machine learning) outperformed the traditional linear, 2-factor interaction, and quadratic models.
The knowledge of physical properties of Bambara Groundnut is not only important in the design of equipment required for handling and processing, but also determines the potential food applications of the grains. Likewise, are the nutritional and microstructural properties that play key roles in the functionality and composition of end products. These properties of Bambara grains are interwoven and variations in them are known to significantly influence the overall grain composition. This chapter discussed the morphology, microstructure, physical properties as well as the nutritional composition (carbohydrate, protein, fat, ash and fibre) of Bambara grains. Comparisons were also made with other legumes for a better understanding of these constituents and grain structure. While few studies have been presented and discussed in this chapter further detailed studies into the properties of Bambara will provide better insights and open door for more effective food application of the grain.
The extraction of bioactive compounds from plant materials has attracted much attention due to their potential therapeutic effects. This article reviews the basic principles, characteristics, and recent applications of infrared assisted extraction (IAE) of bioactive compounds from plant materials. The advantages and disadvantages of IAE are considered, and operation mode and technological improvements, processes, solvents used and other future developments are identified. The review indicated that IAE was a simple, rapid, and cost-effective technique with the capacity for industrial scale application. Future research should focus on energy consumption reduction, green chemistry extraction processes, simplified operation steps, intelligent extraction process, and the establishment of kinetic and thermodynamic models. This article provides a comprehensive understanding of the principles and applications of IAE for the preparation of bioactive compounds, which will be of benefit to researchers and users of the technology.
Heat treatment is a common operation in grain processing technology. Thermal action on grain is characterized by temperature level and duration. Also, the grain changes all its complex properties. Frequently, the temperature in grain activates the process of change in the moisture content and is accompanied by moisture loss. The processes of change in the heat and moisture are interrelated. Based on the experiments conducted on legumes (different varieties of bean, white lupin), a mathematical model of these processes has been developed and the appropriate non-linear differential equations have been used. The obtained equations cannot be solved either analytically or numerically, because some of the coefficients are unknown. The equations are solved based on certain assumptions. Based on these assumptions, the paper provides the calculation of the change in temperature and moisture content over time in legumes, such as bean and white lupin. The obtained results have been compared with experimental data.
The present study was aimed to evaluate the differences among anti-nutritional factors in relation to mineral absorption and protein digestibility of Easy-to-cook (ETC) and Hard-to-cook (HTC) grains from different kidney bean (KB) accessions.HTC grains showed lower a* (redness to yellowness) and b* (greenness to blueness) values and L* value than ETC grains. HTC grains had significantly higher Ca and Zn and lower Cu, Mn and Fe than ETC grains. ETC and HTC grains showed significant variation in mineral, total phenolic content (TPC), tannin and phytic acid content. TPC and tannin content were significantly higher for HTC grains, on the contrary phytic acid content was lower than counterpart ETC grains. Protein and in vitro protein digestibility (IVPD) also varied significantly between HTC and ETC grains and was found to be lower for HTC grains. Majority of phenolic compounds (PCs) were present in bound state in both ETC and HTC grains. Moreover, HTC grains showed higher amount of chlorogenic acid and catechin content than ETC grains in bound form. ETC and HTC grains from dark color accessions showed higher catechin content.
Pulses are good sources of bioactive compounds such as polyphenols, phytosterols and non-digestible carbohydrates that play important physiological as well as metabolic roles. These compounds vary in concentration amongst different pulse species and varieties. Pulse seed coats are rich in water-insoluble fibres and polyphenols (having high antioxidant activities), while cotyledons contain higher soluble fibres, oligosaccharides, slowly digestible and resistant starch content. Ferulic acid is the most abundant phenolic acid present in pulses, while flavonol glycosides, anthocyanins and tannins are responsible for the seed coat colour. Sitosterol (most abundant), stigmasterol, and campesterol are the major phytosterols present in pulses. Pulse fibres, resistant starch and oligosaccharides function as probiotics and possess several other health benefits such as anti-inflammatory, anti-tumour, and reduce glucose as well as lipid levels. Beans and peas contain higher amounts of oligosaccharides than other pulses. Processing methods affect resistant starch, polyphenol composition and generally increase antioxidant activities of different pulses. In this review, the current information on pulse polyphenols, phytosterols, resistant starch, dietary fibre, oligosaccharides, antioxidant and associated health benefits are discussed.
Legume seeds are concentrated sources of cheap, widely available protein, and consequently a vital food resource worldwide. The grain legumes Canavalia ensiformis, Phaseolus vulgaris, Phaseolus lunatus, Vigna unguiculata and Mucuna pruriens are cultivated in the tropics of Mexico and other countries where cereals are a dietary staple. Grain legume nutritional value depends largely on nutrient content and the presence or absence of antinutritional and/or toxic factors. This review addresses certain important chemical components and antinutritional factors in these five legumes, as well as current techniques effective in reducing or eliminating antinutritional and toxic factors. A food's nutritional value constitutes its ability to provide usable forms of nutrients such as protein, carbohydrates, vitamins and minerals. Grain legumes are protein-rich but contain a wide variety of chemical substances which can degrade their nutritional value when ingested by animals and humans. Antinutritional factors are substances generated in natural feed stuffs through normal metabolism which, when ingested, can compromise optimum nutrition through mechanisms such as nutrient inactivation, and/or interference with the digestive process and metabolic feed utilization. Antinutritional factors can be acutely toxic (e.g. some lectins, cyanogenic glycosides, non-protein amino acids [NPAAs]), unpalatable (e.g. tannins or NPAAs) and/or antinutritional. The latter effect (e.g. phytates), metabolic inhibition (e.g. NPAAs, cyanogenic glycosides, isoflavones, alkaloids) and/or digestion interference (e.g. protease inhibitors, lectins, etc.). Humans have probably been processing grain legumes to partially or completely remove or inactivate antinutritional factors since the Neolithic, when these grains first formed part of agricultural systems. Early techniques most likely involved heat treatment to destroy thermolabile compounds and/or leaching to remove others. Several techniques are currently available to minimize antinutritional factor impact in grain legumes and improve their utilization (e.g. genetic manipulation). This overview is part of an on-going effort to stimulate interest in the production and use of tropical grain legumes by promoting a better understanding of their nutritional value, the importance of reducing or eliminating their antinutritional factor content, and the functional properties of flours and products derived from them.
The term ‘micronization’ is often used to refer
to a process of heat treatment of grains at high temperature
for a relatively short time processing using near-infrared
radiation. Recently there is an increasing interest in the
application of micronization as a processing technology for
grains. When cereals/legumes with sufficient moisture are
subjected to micronization, some beneficial changes like
partial gelatinization of starch, inactivation of enzymes that
are responsible for the degradation of quality and denaturing
of antinutritional factors are observed. The partial
gelatinization due to micronization improves starch
digestibility and palatability and reduces the cooking time
without significantly affecting other nutrients present in
grains. Micronization is applied in the commercial production
of quick cooking pulses, flaked cereals and toasted
products. This review mainly deals with recent studies on
micronization of pulses and cereals used as food and feed
and the effect of micronization on product quality and
cooking characteristics.
The selective far-infrared (FIR) heating concept was applied to inactivate spores of Aspergillus niger and Fusarium proliferatum in corn meal. The selective heating method proposed denatures protein constituents in the spectral range between 5.88 and 6.66 μm, demonstrating an enhanced (∼40% in 5 min heating) lethality, compared to normal infrared (IR) radiation. A thermal death kinetics model based on the dynamic temperature profile to predict survivors under time varying conditions was developed to validate the selective IR heating process. The proposed dynamic thermal death kinetics model concept can be extended to other inactivation process.
The objective of the presented work was to determine the effect of infrared heating on the physicochemical characteristics of Mexican common bean flour. Variety of Pinto Villa beans were used in the present experiment. Infrared heating was fitted at 0, 10, 20 and 40 Hz. Power absorption, relative crystallinity by X-ray diffraction, proximate analysis, water absorption capacity, water absorption index, viscosity, and total, resistant and available starch methods were used to characterize the common bean flour. X-ray diffraction data showed changes in the diffraction patterns attributable to the possible formation of amylose–lipid complex. Water absorption capacity (WAC) and water absorption index (WAI), as well viscosity profiles, were affected by changes in the starch and protein content. Sample with highest power absorbed (20 Hz) show highest values of WAC and WAI and lowest value of viscosity. The content of resistant starch (RS) was highest at medium absorbed power (10 Hz).
Purpose
Legumes are widely grown and are consumed as a source of plant protein throughout the world. They rank second after cereals with respect to their consumption order. Legumes have anti‐nutritional factors which make their uses limited. This study aims to check the effect of soaking and cooking on the anti‐nutrient contents and nutritional quality of the legumes.
Design/methodology/approach
Five legumes (white kidney bean, red kidney bean, lentil, chickpea, and white gram) frequently used by the masses were selected for soaking and cooking trials. Legumes were tested for their weight, volume, density, swelling capacity and water absorption capacity before soaking and cooking. Legumes were soaked in simple water, 2 per cent sodium chloride solution, acetic acid and sodium bicarbonate and cooked in a beaker with 1 : 5 seed water ratio to uniform soft mass. After soaking and cooking, legumes were tested for anti‐nutrients (phytic acid and tannin) and their nutritional quality.
Findings
The statistical analysis of the study results revealed that dark colour legume (red kidney bens) has a high level of phytic acid and tannin compared with light colour (white kidney beans and white grams). Soaking and cooking of legumes result in significant reduction in phytic acid and tannin contents. Maximum reduction of phytic acid (78.055) and tannin (65.81 per cent) was found for sodium bicarbonate soaking followed by cooking. These treatments also result in a slight reduction in nutrients such as protein, minerals and total sugars.
Practical implications
Soaking and cooking of legumes reduce their anti‐nutrients; phytic acid and tannin significantly. These treatments may be used domestically as well as commercially to increase the nutrients' availability from legumes to meet the problem of protein and minerals deficiencies.
Originality/value
Along with water different soaking solutions which are easily available in the market were used to test out their effect on the nutritional quality and safety. These may be used by the common people to raise their nutritional status.
Microwaves are known to induce compositional, nutritional and functional changes in majority of the food systems. The objective of the present studies was to investigate the effect of microwave heating on protein solutibility and on the functional properties of a cereal, legume and their blends as such information will facilitate the processing and new product developments consisting of the above ingredients. The three samples i.e. a cereals (wheat flour & haleem flour) legumes (red bean flour) were used to evaluate the effects of microwave heating on their functional properties such as the water holding, oil binding, emulsifying, foaming capacities and the protein solubility index. It was found that all the microwave treated (MWT) samples produced significantly enhanced values of the above mentioned characteristics as compared to the microwave untreated (MWU) counter parts. The time for MWT as 50 s, 90 s and 300 s was found to alter the functionality of the three selected flours. Protein solubility in general was increased during MWT for a short period of time and decreased with increase in the time of treatment. The results have indicated that MWT of the raw materials for a limited time period will be helpful in designing the processing system and determining the quality of processed foods.
Pulses (pea, chickpea, lentil, bean) are an important source of food proteins. They contain high amounts of lysine, leucine, aspartic acid, glutamic acid and arginine and provide well balanced essential amino acid profiles when consumed with cereals and other foods rich in sulphur-containing amino acids and tryptophan. The protein content of most pulse legumes fall within the range of 17–30% (d.w.b.). Apart from their nutritional properties, pulse proteins also possess functional properties that play an important role in food formulation and processing. Examples of such functional properties include solubility, water and fat binding capacity and foaming. Various research studies indicate that some functional properties of pulse proteins may be comparable to those of other frequently used proteins such as soy and whey. The functional properties of pulse proteins have been exploited in the preparation and development of products such as bakery products, soups, extruded products and ready to eat snacks. The growing body of research on the health benefits associated with the consumption of pulses has increased interest in developing innovative technologies to expand the use of pulses in food products. At the same time, there are growing global food security challenges and protein malnutrition continues to be a problem in many countries around the world. Pulses, especially when blended with cereal proteins, may offer a promising alternative source for nutritional and functional proteins. This review provides an overview of the characteristics of pulse proteins, current and emerging techniques for their fractionation, their major functional properties and opportunities for their use in various applications.
Bambara groundnut seed is an indigenous legume with good protein quality. However, the cooking time (3 h) has contributed to its under-utilisation. In this study, the effects of pre-soaking bambara groundnut seeds with or without dehulling (whole and dehulled), followed by infrared heating (130 °C, 0, 5, 10 and 15 min) on their cooking characteristics were studied. As infrared heating time increases (0, 5, 10 and 15 min), soluble pectin increased and cell wall separation was enhanced in the grains. Water absorption during soaking and cooking (whole and dehulled) were higher in infrared heated samples compared to untreated. The rate of water absorption during cooking (95 °C) was higher in pre-soaked whole and dehulled bambara groundnut after infrared heating treatment for 15 min compared to untreated seeds. Further, the cooking times of untreated whole (162 min) and dehulled (41 min) was reduced to about 60 min and 30 min respectively after infrared heating of pre-soaked seeds for 15 min. With or without dehulling, infrared heating especially at 15 min can produce bambara groundnut seeds with short cooking time limiting energy demand in both urban and rural communities in Africa.
Functional properties of flours from pre-soaked and micronised (130 °C) whole and dehulled bambara seeds (5, 10 and 15 min) were determined. An increase in micronisation time significantly reduced the pasting viscosity of the flours. Significant reductions in the differential scanning calorimetry endothermic peak enthalpies and loss of birefringence in the starch were found, indicating starch pre-gelatinisation when micronised. The low viscous paste of resultant flours seems to be related to protein denaturation as shown by decrease in nitrogen solubility index. Starch was embedded in a protein matrix as shown by confocal laser scanning microscopy. This denatured protein matrixes could be in part preventing starch hydration and dispersion during pasting and thus reduced viscosity. Dehulling reduced the pasting viscosity suggesting higher effect of micronisation for dehulled than whole samples. Resulting flours can be useful ingredients in protein energy-dense foods due to low viscosity.
This study was conducted to evaluate the effects of infrared irradiation for 60, 90, 120 and 150 seconds on starch degradability and chemical compositions of corn grains. Three ruminally fistulated rams were used to measure in sacco degradation. There was a linear increase in DM of irradiated corn grains (P<0.001). Infrared irradiation decreased potentially degradable fraction and constant degradation rate of starch (P<0.05). Effective ruminal degradability of starch for irradiated corn grain decreased linearly (P<0.001) as irradiation time increased.
A mathematical model of temperature and moisture changes for granular material exposed to infrared (IR) heat processing (micronization) was developed. The model was based on a radiation exchange principle in an enclosure composed of diffuse-gray surfaces. The validation of the model was performed for experiments conducted with peas tempered to three initial moisture contents of 20%, 25%, and 30% w.b. (wet basis). The simulation results were in good agreement with the experimental values. Further simulation experiments quantified the effect of such micronization variables as the temperature of the IR emitter, emissivity, configuration factor, temperature of the conveying trough, temperature of the surroundings, and emissivity of the processed material.
Soybeans (SBs) were obtained from five leading SB-producing countries (Argentina, Brazil, China, India, and the United States), imported to the United States, and processed into soybean meal (SBM) under uniform conditions in the United States. SBs from China had the highest crude protein (CP) content while SBs and the resultant SBM from Argentina had the lowest. Additional differences in the quality of the SB and resultant SBM samples collected were noted. An additional set of SBM produced in these five countries and subjectively evaluated to be of low, intermediate, and high quality also were obtained and evaluated. Overall, SBM quality affected amino acid and mineral concentrations with differences existing both among and within countries. SBM produced in the United States had a higher CP content than SBM produced in other countries. Amino acid concentrations generally increased, and antinutritional factors decreased with increasing subjective quality assessment.
The objective of this study was to determine the effects of micronization (high intensity infrared heat) on water hydration rate and cooking time of split peas, and the functional properties of the protein and starch components in the micronized peas. Split peas at 26% moisture content were micronized for 90 s using a 500 W infrared tubular quartz lamp to a final moisture of 15% without affecting the exterior or interior color of the peas. Micronization increased water hydration rate by 7% and cooking time was decreased by one-third. The pea proteins were denatured and starch granules pregelatinized by the heat treatment so that granule disintegration was enhanced during amylography. Micronization was an effective technique for instantizing split peas and expanding food uses for dry peas.
Retention of water‐soluble nutrients, prevention of solid loss and elimination of waste water generation are some of the advantages of dry blanching. Dry blanching of red bell pepper ( C apsicum annuum L .) slices using infrared ( IR ) and microwave ( MW ) radiations was attempted and its performance was compared with conventional water and steam blanching methods. Processing conditions (time and temperature) were standardized on the basis of degree of enzyme inactivation (peroxidase, polyphenol oxidase). Effect of blanching methods on retention of micronutrients such as ascorbic acid, β ‐carotene and protein, besides product shrinkage, structure and texture (shearing force) were analyzed. Water and steam blanching were found to need lower processing time (1.0 and 1.5 min, respectively) compared with IR (6.0 min) and MW blanching (3.0 min). However, MW ‐blanched samples retained higher amounts of ascorbic acid (94.7%). Dry blanching with IR (150 C ) and MW (17.5 W /g) resulted in higher retention of β ‐carotene (103.2 and 118.6%, respectively) compared with water (60.3%) and steam blanching (88.3%). Dry blanching resulted in moisture loss (1–6%) and shrinkage, perhaps resulting in higher shearing force observed in dry blanched slices. Scanning electron micrographs indicated that method of blanching has a role on extent of effect on cell structure.
Practical Applications
Red bell pepper is a rich source of ascorbic acid and β ‐carotene. This study explored the possibilities of dry blanching red bell pepper using infrared and microwave radiation as a potential alternative to water and steam blanching. The dry blanching is expected to retain higher amount of nutrients, reduce solid loss and eliminate effluent generation besides being convenient to operate.
Microwave heating has vast applications in the field of food processing such as cooking, drying, pasteurization and preservation of food materials. In this article, various applications of microwave food processing such as microwave cooking, microwave pasteurization and microwave assisted drying were extensively reviewed. The advantages and the factors affecting the microwave cooking of food materials have been reviewed. Microwave pasteurization of fresh juices, milk and various food products has been elaborately discussed. Microwave pasteurization has the ability to achieve destruction of microorganisms at temperatures lesser than that of conventional pasteurization due to significant enhancement or magnification of thermal effects. Applications of microwave drying include microwave assisted hot air drying, microwave vacuum drying and microwave freeze drying. Microwave drying combined with other conventional methods of drying enhances the drying characteristics of the sole effect of microwave drying. Modeling of microwave heating of food materials based on Maxwell's equations and Lambert's law equations have been reviewed along with their applications. Microwave modeling can be used to predict the temperature and moisture distributions during microwave heating of food materials. The factors affecting the dielectric property of food material and the applications of dielectric property measurements were also discussed. Various solution strategies to overcome non-uniform temperature distribution during microwave heating of food materials were proposed. It is required to obtain better end product qualities of food materials by conducting more research at pilot scale levels. It is also necessary to eliminate hot spots or non-uniform temperature distribution during microwave heating of food materials.
Far-infrared heating has recently been adopted for use in certain food processing applications, because of its superiority in terms of costs and the quality of the products as compared with conventional heating. This article surveys the possible applications of far-infrared heating for baking (roasting), drying, thawing and pasteurization in the food industry.
Tempering pretreatments were evaluated for the micronization of navy and black beans. Navy and black beans were tempered to 28g/100g and 26g/100g moisture, respectively, using water, a mixture of salts of bicarbonate, carbonate and phosphate, a mixture of citric acid and ascorbic acid, or ethylenediaminetetraacetic acid (EDTA) and monitored for texture after cooking, and changes in starch, protein and colour. The mixture of sodium bicarbonate, sodium carbonate and dibasic sodium phosphate was more effective than the mixture of citric and ascorbic acid or disodium EDTA or water alone in reducing the hardness of micronized black beans, while the water and salt mixture were equally effective in reducing the hardness of navy beans and the firmness of both navy and black beans. Lower soluble protein levels and higher levels of gelatinized starch were significantly correlated with a decrease in the hardness of micronized beans. Colour was affected for all micronized black beans, but the colour of micronized navy beans was only affected by the acid treatment. The ability of the bean to imbibe and distribute water in its seed renders seed constituents more sensitive to the effect of heat and solutes, thereby influencing the tempering strategy.
This review has presented the principles underlying the dielectric heating effects observed for chemical compounds in solution and in the solid state. The applications of the technique to a wide range of chemical syntheses have also been indicated. The field is in its infancy and therefore much of the effort to date has been directed towards understanding the rate enhancements of known reactions. The next few years should see the isolation of new compounds using microwave heating techniques
Bambara groundnut (Vigna subterraenea (L.) verdc) (BGN) is a legume; its origin have been traced back to Africa, and it is the third important legume; however, it is one of the neglected crops. It is highly nutritious, and has been termed a complete food. Its seed consist of 49%-63.5% carbohydrate, 15%-25% protein, 4.5%-7.4% fat, 5.2%-6.4% fiber, 3.2%-4.4% ash and 2% mineral compared to whole fresh cow milk 88% moisture, 4.8% carbohydrate, 3.2% proteins, 3.4% fat, 0.7% ash, and 0.01% cholesterol. Its chemical composition is comparable to that of soy bean. Furthermore, BGN has been reported to be a potential crop, owing to its nutritional composition, functional properties, antioxidant potential, and a drought resistant crop. Bambara groundnut milk (BGNM) had been rated higher in acceptability than milk from other legumes like soybean and cowpea. Probiotics have been defined as live microorganisms which when administered in adequate amount confer a health benefit on the host. These benefits have been reported to be therapeutic, suppressing the growth and activity in conditions like infectious diarrhea, irritable bowel syndrome, and inflammatory bowel disease. The nutritional profile of BGNM is high enough to sustain the growth of probiotics. BGNs are normally boiled and salted, eaten as a relish or roasted, and eaten as a snack. Hence, BGNM can also be fermented with lactic acid bacteria to make a probiotic beverage that not only increase the economic value of the nutritious legume but also help in addressing malnutrition.
The physicochemical, functional, and thermal properties of protein isolates obtained from two varieties of Bambara groundnut were evaluated. Proteins were isolated using alkaline extraction (isoelectric precipitation [IEP]) and micellisation techniques. IEP recorded a higher protein yield (56.3–58.2 g/100 g) than the micellised protein (MP) (14.2 – 15.6 g/100 g). A similar trend was observed for the protein content of the isolates. The isolates contained a high level of lysine, arginine, and glutamic acid compared to soy protein. Minimum solubility of the flours of the two varieties occured at pH 5. MP isolates exhibited higher solubility than the corresponding isoelectric (IEP) isolates over all pH values. The micellised protein recorded superior functional characteristics than the isoelectric isolates. The micellised isolates also showed a significantly higher (P < 0.05) foam capacity and stability, oil and water absorption properties than the isoelectric isolate. The MP of both varieties also recorded significantly higher emulsifying properties-+ than their isoelectric protein isolates. The micellised protein also had better gelation properties than the isoelectric isolate. Micellised and isoelectric isolates did not reveal major differences in the electrophoretic patterns; both isolates had three major bands at 35.0, 43.0, and 112.0 kDa. The bands in the isoelectric protein isolate however, were well defined compared with the micellised isolate. All Bambara isolates were not dissociated by 1,4-Dithiothreitol (DTT) suggesting that they do not contain subunits linked by a disulphide bond. This suggests that 7S vicilin may be the major storage protein in Bambara groundnut isolates. Differential scanning calorimetry studies (DSC) of the two varieties of bambara groundnut proteins indicated that the thermograms of the micellised isolates have a higher denaturation temperature Td (97.9–108.4°C) than their corresponding isoelectric isolates (89.5–90.6°C).
Background:
Cowpea is mostly utilised as cooked whole seeds. This is often achieved only after boiling for up to 2 h, resulting in high energy consumption and a long time for food preparation. Micronisation of pre-conditioned cowpeas reduces their cooking time. Micronisation changes the physicochemical properties of cowpea seeds, which may affect the sensory properties of cooked cowpeas. Consumer acceptance and utilisation of micronised cowpeas depend on their sensory properties. Micronised and unmicronised samples of Blackeye, Bechuana white, Glenda and Dr Saunders cowpeas were subjected to cooking time, descriptive sensory and colour analyses.
Results:
Micronisation significantly reduced cowpea cooking time by 28-49%. There were significant (P < 0.05) increases in roasted aroma and flavour, mushy texture and splitting in all micronised samples. Bechuana white was more mushy and split than others. There were significant decreases in firmness, mealiness and coarseness after micronisation for all cowpea types. Micronised cowpeas were darker (lower L* values) than unmicronised cooked cowpeas. Darkening was more evident in light-coloured than dark-coloured cowpeas.
Conclusion:
Micronisation reduces cowpea cooking time but also affects sensory properties of cowpeas such as introducing roasted flavours that may not be familiar to consumers. This might have an influence on consumer acceptance of micronised cowpeas.
Black beans (Phaseolus vulgaris) were stored for 10 months under three environmental conditions [high temperature/humidity (HTHH: 30°C, 85% RH); medium temperature/humidity (MTMH: 25°C, 65% RH); low temperature/humidity (LTLH: 15°C, 35% RH)] in order to determine changes in starch and protein and to assess their contribution in textural defects. Hard-to-cook defect developed in HTHH-stored seeds and partially in MTMH samples. An increase in the DSC peak starch gelatinization temperature during storage at all three conditions was not related to hardening. Five protein fractions were separated by gel filtration. A significant increase (p < 0.05) was found during storage for a low-MW fraction of HTHH and MTMH extracts. At the same time a high-MW fraction decreased significantly (p < 0.05), suggesting the breakdown of large proteins. After 10 months of storage, free aromatic amino acids increased significantly (p < 0.05) with increasing temperature and humidity of storage. The coincidence of the appearance of small polypeptides and aromatic amino acids with the development of the hard-to-cook defect suggested a relation between these phenomena.
Effect of gamma irradiation on Vigna unguiculata subsp. unguiculata seeds (maroon-coloured seed coat) at various doses (2, 5, 10, 15 and 25 kGy) on the physicochemical properties, proximate composition, vitamins (niacin and ascorbic acid) and antinutritional factors were analysed. No significant changes were recorded in the physicochemical properties of irradiated seeds. Gamma irradiation resulted in a significant increase in crude protein, while the crude lipid, crude fibre and ash contents resulted in a dose-dependent decrease. Gamma-irradiated seeds presented a significant decrease in the ascorbic acid and niacin content. Irradiation processing significantly reduced the level of L-DOPA, phytic acid, hydrogen cyanide, trypsin inhibitor activity, oligosaccharides and lectins. The total free phenolics, tannins and in vitro protein digestibility on irradiation showed a significant dose-dependent increase. Gamma irradiation seems to be a good procedure to improve the quality of legume seeds from the nutritional point of view.
Summary Five legume seeds (kidney beans, green peas, black beans, lentil and pinto beans) were heated by infrared to a surface temperature of 140 °C. The changes in chemical composition, physical, mechanical and functional properties of the processed seeds were measured and compared to those of the raw seeds. Significant changes in the properties of the seeds in terms of increased volume, lower rupture point and toughness, higher water uptake and higher leaching losses (when the seeds were soaked in water) were obtained. The changes in the physical and mechanical properties were attributed to possible cracking of the seed. Even though trypsin inhibitor activity was reduced, infrared heating did not significantly affect the starch and protein components of the seeds. The functional characteristics of flour from the infrared-heated seeds were superior to those of flour from untreated seeds.
Laird No. 1 lentils micronized (high-intensity infrared heat) to give internal temperatures of 138 and 170 °C were compared to unprocessed lentils stored at room temperature. Micronized lentils, which had been tempered to 33% moisture for 16 h, required less force to compress after cooking and contained increased levels of gelatinized starch and pectic substances but decreased levels of soluble protein, phytic acid, and neutral detergent fiber compared to the unprocessed lentils. Cell walls in the micronized lentil were less susceptible to fracture, and the microstructure was more open. Properties of the micronized lentils were better when the internal temperature reached 138 °C. When micronized to an internal temperature of 170 °C, cooked lentils were harder, possibly due to greater moisture losses and a change in the neutral detergent fiber. Micronization resulted in a slight darkening of the lentils, and this was accentuated at 170 °C.
Soaking and cooking treatments: were evaluated to establish the relationship of various regimes to the development of cooked bean texture and flavor of black beans (Phaseolus vulgaris L.). A salt combination soaking solution was most effective in promoting bean softening during cooking, compared to no soaking or a distilled water soak. A high correlation was observed between objective and sensory texture scores. An Instron puncture force of.150g (0.14 cm probe, 5 cm/min) accurately defined the “eating-soft” limit of texture acceptability.
Black beans stored for 7–14 days at 41°C, 100% RH, required more cooking time than fresh beans and thus paralleled cooking time for beans stored forr more than 1 yr at room temperature. With corrections for solids lost during soaking, water absorption did not differ between fresh and stored beans. The rate of electrolyte leakage was greater from stored beans than from fresh samples, indicating that the cotyledon deteriorated during aging. Bean moisture content was found to be related to cooking time. In general, the higher the moisture content after soaking, the shorter the cooking time. However differences in cooking times between fresh and aged samples persisted regardless of bean moisture content.
Whole hulless and pearled barley were subjected to infrared heating (micronization) at moisture contents between 12.2% and 26.5% and surface temperatures of 105C to 150C. Infrared heat processing markedly affected the functional, structural and physical properties of the grains. Both micronizing temperature and initial grain moisture content had pronounced effects on these characteristics. the characteristics evaluated are bulk and particle densities, water absorption of whole kernel when soaked for 4 h and 24 h, flour water hydration capacity, protein solubility at pH of 2.0 to 12.0 and flour thermal properties using differential scanning calorimetry. Infrared heating did not change the chemical constituents (starch, protein, total dietary fiber, ash and fat) of hulless and pearled barley.
The relationship between the physicochemical and cooking properties of yellow peas was examined in this study. A positive correlation was found between seed weight and water hydration capacity. The Peleg model, which was modified, could be used to describe the water absorption characteristics of peas and could be used to predict the rate of water absorption in the initial water absorption period. Cooking time could be measured objectively using the Mattson cooker. Cooking time was found to decrease with an increase in water hydration capacity. Hardness of cooked peas, measured using a texture analyser, was negatively correlated with both seed weight and water hydration capacity. Seed coats had a significant effect on water hydration and cooking quality of peas. Peas with relatively thin seed coats exhibited higher water hydration capacity, shorter cooking times and softer texture after cooking. The effects of soaking and cooking on trypsin inhibitor activity (TIA) and oligosaccharide levels in peas were also studied. Cooking was more effective than soaking in reducing TIA levels and oligosaccharides (raffinose, stachyose and verbascose) in peas. Copyright © 2003 Society of Chemical Industry
Five landraces of bambara groundnut (Vigna subterranea) from northern Ghana were assessed for their physical characteristics, chemical composition and the effects of variety and processing on quality and consumer appeal for use in food products. The cultivars had distinct colour differences ranging from cream through brown, maroon to black, with variations in the seed sizes and seed coat thicknesses. Significant (P < 0.05) differences were observed in some of the chemical components of the different varieties of bambara. Protein and fat contents ranged from 19.3% to 27.1% and 4.8% to 7.0%, respectively, while ash content was not significantly (P > 0.05) different among the cultivars. Tannin content ranged between 4.5 mg CE g−1 sample for the cream-coloured and 14.9 mg CE g−1 sample for the black variety. Dehulling increased the protein content, reduced tannin content by up to 92% and improved the colour of bambara products, while heat treatment enhanced their taste, aroma and overall acceptability.
Hard-to-cook and easy-to-cook bean and lentil seeds were boiled in water containing calcium ions at concentrations of 0, 40, 80, 120 and 160 mg L−1 and their texture and concentration of phytate and various peptic compounds were measured. In order to minimise matrix effects, hard-to-cook seeds were prepared from easy-to-cook seeds by soaking them at 50 °C. It was found that, as calcium ion concentration increased, phytate concentration decreased and seed hardness increased. Also, during soaking and cooking, phytate and peptic compounds were leached into the water. Losses were larger for hard-to-cook seeds than for easy-to-cook seeds. These results are consistent with the proposed theory that the formation of hard-to-cook legume seeds involves an interaction among divalent cations, phytate and peptic compounds, which is based on the phytase–phytate–pectin hypothesis. Copyright © 2007 Society of Chemical Industry
Bechuana white cowpeas were micronised to three temperatures (130, 153 and 170 °C). Cooking properties of the cowpea seeds and the role of starch-related properties were studied. In all cases, micronisation significantly reduced the cooking time and thus the time required for the cowpea seeds to attain a suitably soft texture. This was attributed in part to the significant improvement in rate of water absorption during cooking and starch pre-gelatinisation, as evidenced by loss of birefringence and increased susceptibility of the cowpea starch to α-amylase digestion. However, micronisation to 170 °C resulted in a severe deterioration in pasting properties of the cowpea flour, possibly due to starch depolymerisation and/or amylose-associated crosslinking. Owing to these changes, cowpea seeds micronised to 170 °C required a longer cooking time than the other two micronised samples. Flour prepared from cowpea seeds micronised to 170 °C may have limited starch functionality. Copyright © 2006 Society of Chemical Industry
The effects of soaking and cooking time on water absorption capacity, cookability, percent split, and texture of two varieties of cowpea, IITA-2246 and IFE-BPC, were investigated. Soaking prior to cooking had an effect only on the cookability, while the amount of water absorbed and the penetration depth (a measure of texture) of a penetrometer head in the seeds increased with cooking time. The properties were found to differ notably for the two varieties with IITA-2246 having a softer texture than IFE-BPC. Splitting in cooked beans increased with cooking time with maximum of 92% split in IITA-2246 and 63% split for IFE-BPC. Higher temperature soaking reduced the cooking time of both varieties.
Soy protein supplementation increases the nutritional value of starch-based expanded snacks. A systematic study was conducted to serve as baseline for optimizing the addition of soy protein concentrate (SPC). Physical and microstructural properties of native corn starch–soy protein concentrate (CS–SPC) extrudates were investigated in relation to the macromolecular changes in starch during extrusion. The effects of extruder screw speed (230 and 330 rpm) and SPC concentration (0%, 5%, 10%, 15%, 20%) on the abovementioned parameters were determined. Increasing screw speed resulted in higher specific mechanical energy (SME) and expansion, and lower mechanical strength. On the other hand, addition of 5–20% SPC led to lower SME and expansion, and higher mechanical strength. X-ray micrographs showed smaller yet more cells, and cell wall thickening with SPC addition. Water absorption index increased and water solubility index decreased with increase in screw speed and SPC level. Increasing screw speed resulted in a slight shift towards smaller molecular weight fractions of starch, as determined by gel permeation chromatography.
Micronisation (infrared heat treatment) following tempering (conditioning) is an effective means of reducing cooking time in grain legumes such as lentils. However, the physical, physico-chemical and chemical changes that bring about this desirable change in the lentils have not been extensively investigated. The objective of this study was to investigate the physical changes occurring in lentils as a result of micronisation at different moisture contents. Lentils were tempered to a range of moisture contents (17–45%) and micronised under an electric microniser to return them to their initial moisture content (13%). Control samples were tempered to the same moisture contents but were air-dried (at 40 °C). Changes in the density and apparent elastic modulus (of a collection of grains) of the processed lentils were measured, as was the diffusion coefficient of moisture into them. Porosity of the micronised lentils increased with increasing tempering moisture, up to approximately 25%, arising from void creation induced by evaporation of moisture. However, porosity decreased at higher tempering moisture contents, presumably due to filling of voids by amylose from partially gelatinised starch granules. Changes in the porosity of air-dried lentils were slight. Apparent elastic modulus of the micronised lentils was essentially unaffected by tempering conditions. The rewetting coefficient of the micronised lentils was significantly greater than that of air-dried lentils, and the difference increased as tempering moisture content was increased. Diffusion coefficients of moisture within the lentils were strongly dependent on tempering moisture content, increasing as tempering moisture increased. The results indicate that rate of hydration of the lentils (a factor in cooking time reduction) depends on the physico-chemical changes brought about by heat and moisture during micronisation as well as on the increase in porosity.
Pulses belong to the family leguminosae (COPR, 1981). The family leguminosae is made up of many species which are cultivated all over the world (Rubatzky and Yamaguchi, 1997). Legumes have a wide range of usage, some are used as fodder or green manure, some are used as silage, while others are extracted for their oil, notably soyabean and groundnut (COPR, 1981). Such oil contributes a great deal to the energy intake of people all over the world. Majority of legumes are grown for their green pods, green seeds, or dried seeds (COPR, 1981). The term pulses cover all those grown for their dried seeds (COPR, 1981). Pulses have a variety of functions. The use of pulses range from their forming a staple diet to their being used as condiments, milk, cheese and snacks (Reddy et al., 1986; Uzogara and Ofuya, 1992). They play a very important role in human nutrition. The present paper reviews the work that has been done on the nutritional value of pulses. Production: Pulses are grown all over the world (Reddy et al., 1986). Production as per continent is shown in the table below.
The effects of a hydrothermal treatment consisting of tempering (to 41% moisture) and heating to 153 °C (micronisation) on the structural and physicochemical characteristics of two cowpea varieties were studied. The untreated varieties had similar cooking times, although cooked Bechuana white cowpeas were significantly (P ≤ 0.05) softer and had a higher incidence of splitting than Var. 462 cowpeas. This may be due in part to differences in cotyledon structure affecting water uptake during cooking. The hydrothermal treatment changed the physical structure and chemical properties of the cowpea seeds. This led to significant (P ≤ 0.05) reductions in the cooking time of micronised Bechuana white and Var. 462 cowpeas, by 47 and 36% respectively, as compared with control samples. Micronisation caused physical fissuring of the seed coat and cotyledon and significantly (P ≤ 0.05) reduced the bulk density of treated seeds. These changes in the physical structure significantly (P ≤ 0.05) improved the initial water uptake during soaking and cooking, increased the enzyme-susceptible starch and reduced the protein solubility and hydration capacity of the cowpea seeds. Cooked (60 min) micronised cowpeas also had significantly (P ≤ 0.05) more splits and a significantly (P ≤ 0.05) softer texture than control samples. Copyright © 2005 Society of Chemical Industry
Total phenolic content (PC) was ∼12 mg g−1 in lentils, 2.2 mg g−1 in chickpeas, 2.3 mg g−1 in soybeans, 2.5 mg g−1 in yellow peas and 1.2 mg g−1 in green peas. Total antioxidant activity (AA) determined by ABTS (2,2′-azinobis-3-ethyl-benzthiazoline-6-sulfonic acid) assay was highest in lentils at around 14 μmol Trolox equivalent antioxidant capacity (TEAC) g−1 and lowest in green peas at 1.9 μmol TEAC g−1. Bound phytochemicals contributed to 82–85% total AA in lentils. Free phytochemicals contributed more to total AA in chickpeas, yellow peas, green peas and soybeans than bound phytochemicals. AA and PC was reduced by ∼80% in lentils and <30% in yellow peas by decortication, by 16–41% in lentils, chickpeas and peas by cooking, and by 22–42% in lentils by soaking. Total AA was significantly correlated with total PC. Soybeans had the greatest ability to scavenge free radicals, inhibit lipid peroxidation and chelate metals among the legumes tested. Different legumes exhibited different AA mechanisms.
Infrared (IR) heating provides significant advantages over conventional heating, including reduced heating time, uniform heating, reduced quality losses, absence of solute migration in food material, versatile, simple, and compact equipment, and significant energy saving. Infrared heating can be applied to various food processing operations, namely, drying, baking, roasting, blanching, pasteurization, and sterilization. Combinations of IR heating with microwave heating and other common conductive and convective modes of heating have been gaining momentum because of increased energy throughput. This article reviews aspects of IR heating and presents a theoretical basis for IR heat processing of food materials and the interaction of IR radiation with food components. The effect of IR on food quality attributes is discussed in the context of samples and process parameters. Applications of IR heating in food processing operations and future research potential are also reviewed.
The antioxidant properties of some commonly consumed [cowpea (Vigna unguiculata)] and underutilized [pigeon pea (Cajanus cajan) and African yam bean (Sphenostylis sternocarpa)] legumes were assessed with regard to their Vitamin C, total phenol, and phytate content, as well as antioxidant activity as typified by their reducing power and free radical scavenging ability. The Vitamin C content of the cowpeas ranged from 0.5 to 0.9mg/100g, while that of underutilized legumes were 0.9mg/100g for pigeon pea and 0.8mg/100g for African yam beans. The phenol content of the cowpeas were 0.3–1.0mg/g, African yam bean had 0.7mg/g total phenols, while pigeon pea contained 0.4 (white) and 1.2mg/g (brown) total phenol content, respectively. The phytate content of all the legumes [cowpea (2.0–2.9%), pigeon pea (2.0–2.4%), African yam beans (2.4%)] analyzed were generally high, while the reducing power and free radical scavenging ability for all the legumes were very low except in African yam beans (23.6%), cowpea brown (29.9%), and pigeon pea brown (54.5%) that had a relatively high free radical scavenging ability. Therefore, one of the commonly consumed cowpea V. unguiculata (brown) and underutilized legumes C. cajan (brown) and S. sternocarpa could be considered as a functional food due to their relatively higher antioxidant activity (free radical scavenging ability and redox potential) which could be as a result of their relative higher total phenol content.
Nitrogen (N) has been gradually depleted from West African soils and now poses serious threats to food production. Many ways of increasing N supply (e.g. judicious use of inorganic fertilizers and nitrogen-fixing plants) have been tried in West African farming systems. Herbaceous and woody legumes commonly contribute 40–70 kg N ha–1 season. This represents about 30% of the total N applied as residues. Nevertheless and despite repeated demonstrations of the usefulness of green manures in enhancing soil fertility, their practices and adoption are still limited. Promiscuous soyabeans are being used to develop sustainable cropping systems in the moist savannah. Reliable estimates of N2 fixed by soyabeans and their residual N benefits to subsequent cereal crops in the savannah zone of southern Guinea have only infrequently been made. The actual amounts measured varied between 38 and 126 kg N ha–1 assuming that only seeds of soyabeans are removed from the plots, the net N accrual of soil nitrogen ranges between minus 8 kg N ha–1 and plus 47 kg N ha–1 depending on the soyabean cultivar. Residual soyabean N values of 10–24 kg N ha–1 (14–36% of the total N in maize) were obtained in a soyabean-maize rotation. Although cereal yields following legume cultivation have been attributed to greater N accumulation, our data show that the relative increase in maize N was smaller than the relative increase in dry-matter yield. Hence, the increased yields of maize following soybeans are not entirely due to the carry-over of N from soyabean residues (as well as to conservation of soil N) but to other rotational effects as well. It is thus clear that the Nbenefit of grain legumes to non-legumes is small compared to the level of N fertilizer use in more intensive cereal production systems but is nevertheless significant in the context of the low amounts of input in subsistence farming.
The proximate composition, mineral constituents and amino acid profile of four important legumes (chickpea, lentil, cowpea and green pea) were studied in order to evaluate their nutritional performance. Significant (P < 0.05) variations existed among the legumes with respect to their proximate composition, mineral constituent and amino acid profile. Lentil was found to be a good source of protein, while cowpea was good in ash among the grain legumes tested. All four types of legumes were also better suppliers of mineral matter, particularly potassium, phosphorus, calcium, copper, iron, and zinc. However, the concentrations of various mineral constituents was not in good nutritional balance. It was concluded that the four legumes tested were rich in lysine, leucine and arginine and can fulfil the essential amino acid requirement of human diet except for S-containing amino acids and tryptophan. In order to make good, the deficiency of certain essential amino acids in legume protein, they must be supplemented with other vegetables, meat and dairy products (e.g., Whey, yogurt).
Application of combined electromagnetic radiation and hot air is gaining momentum in food processing. A combined infrared and hot air heating system was developed for drying of vegetables. A conveyorised drying system having three chambers was fitted with mid-infrared (MIR) heaters for radiative heating. Through-flow hot air circulation was also provided for convective mode heating. The system was designed to operate under infrared, hot air and combination mode independently. The performance evaluation studies indicated that combination drying of carrot and potato at 80 °C with air at a velocity of 1 m/s and temperature of 40 °C reduced the drying time by 48%, besides consuming less energy (63%) compared to hot air heating. Combination drying also gave better results over infrared heating alone. The energy utilization efficiency of the dryer was estimated to be 38% for both carrot and potato drying.
Functional properties of cowpea flour from seeds micronised at two different surface temperatures (130 and 170 °C) were studied. Micronisation (130 and 170 °C) significantly (P ⩽ 0.05) increased the water absorption capacity and least gelation concentration of the flour. The treatment significantly (P ⩽ 0.05) reduced the water solubility and swelling indices, gel strength and foaming capacity of the flour. The changes in cowpea flour functional properties, such as the loss of foaming capacity in flours from micronised (130 and 170 °C) seeds, were associated with significant (P ⩽ 0.05) increase in the surface hydrophobicity and cross-linking of the cowpea protein. SDS–PAGE of the protein-rich fractions revealed changes in the protein subunit profile which included the formation of disulphide bonds and possibly Maillard cross-links. The flour from M-170 °C seeds was significantly (P ⩽ 0.05) darker than was the flour from unmicronised and M-130 °C seeds.
An infrared dryer was developed and infrared radiation thin layer drying of onion slices was carried out at infrared power levels of 300, 400 and 500 W, air temperatures of 35, 40 and 45 °C and air velocities of 1.0, 1.25 and 1.5 m/s. The drying occurred in the falling rate of drying period. Drying rate increased with increase in infrared power at a given air temperature and velocity and thus reduced the drying time. The drying time increased with increase in air velocity at a given infrared power and air temperature because of the increased cooling effect at the surface of the product. Eight available moisture-ratio models were fitted to the drying data. Page’s model had a higher correlation coefficient and low chi-square value and thus predicted drying behaviour of the onion slices more accurately.