Changes in odor characteristics of pulse protein isolates from germinated chickpea, lentil, and yellow pea: Role of lipoxygenase and free radicals

Assessing the impact of bacterial blends, crosslinking enzyme and storage times on volatile and non-volatile compound production in fermented pea protein emulsion gels

Pea protein is a promising ingredient for plant-based cheese production but has poor consumer acceptance due to intrinsic beany flavors. Fermentation could potentially decrease these off-flavors while also producing desirable cheese-like aromas. Pea protein emulsion gels were fermented using four different bacterial blends for 16 weeks with and without the crosslinking enzyme transglutaminase. The volatile organic compound (VOC) profiles were assessed by GC-MS and the peptide profile was measured by LC-MS/MS during storage. VOC production was mainly affected by the composition of the bacterial blends, followed by storage time. Crosslinking of the protein gel structure had minimal impact on VOC production. The peptide-level profiling revealed that crosslinking can reduce peptide size and the production of bitterness-like peptides in some blends. This study provides insights into the effect of bacterial blends, storage time, and enzymatic crosslinking on the production of volatile components and peptides related to aroma and peptide profiles for pea protein.

Impact of a Novel Two-Phase Natural Deep Eutectic Solvent-Assisted Extraction on the Structural, Functional, and Flavor Properties of Hemp Protein Isolates

Defatting dehulled hemp seeds is a crucial step prior to protein extraction. However, conventional methods rely on flammable solvents, posing significant health, safety, and environmental concerns. Additionally, hemp protein has poor extractability, challenging functionality, and flavor limitations, restricting its broader application in foods. Accordingly, a two-phase natural deep eutectic solvent (NADES)-assisted extraction was evaluated as a solvent-free alternative for co-extracting protein and oil from full-fat hemp flour. In comparison to the reference hemp protein isolate (R-HPI), produced from hexane-defatted flour following conventional alkaline extraction, NADES-extracted hemp protein isolate (N-HPI) had significantly higher protein extraction yield and purity. N-HPI exhibited enhanced surface charge, lower hydrophobicity, and thus higher solubility at an acidic pH compared to R-HPI. N-HPI had a higher abundance of edestin and lower levels of vicilin-like proteins, which contributed to superior gelation compared to R-HPI. N-HPI, compared to R-HPI, contained lower levels of lipid-derived off-flavor compounds, such as aldehydes, alcohols, and ketones. These findings highlighted, for the first time, the potential of a two-phase NADES-assisted extraction as a sustainable alternate and effective process for producing high-quality, functional hemp protein. The development of such a green process is an impetus for broadening the applications of hemp protein in food systems.

Effects of Maillard Reaction Durations on the Physicochemical and Emulsifying Properties of Chickpea Protein Isolate

This study investigated the physicochemical and emulsifying properties of chickpea protein isolate (CPI)-citrus pectin (CP) conjugates formed via the Maillard reaction across varying reaction durations. CPI and CP were conjugated under controlled dry-heating conditions, and the resulting conjugates were characterized by measuring their particle size, zeta potential, solubility, thermal stability, surface hydrophobicity, and emulsifying properties. The results showed that as reaction duration increased, the particle size and zeta potential of the CPI-CP conjugates increased significantly, reaching a maximum particle size of 1311.33 nm and a zeta potential of -35.67 mV at 12 h. Moreover, the Maillard reaction improved the solubility, thermal stability, and hydrophobicity of the CPI. Glycosylation increased the emulsifying activity index (EAI) and emulsifying stability index (ESI) of the CPI to 145.33 m2/g and 174.51 min, respectively. Optimal emulsions were achieved at a protein concentration of 1.5 wt% and a 10% volume fraction of the oil phase. The Maillard reaction promoted the interfacial protein content and the thickness of the interfacial layer while decreasing the droplet size and zeta potential of the emulsion. Additionally, the emulsion prepared with CPI-CP-12 h showed outstanding long-term stability. These results demonstrate that a moderate Maillard reaction with CP effectively enhances the physicochemical and emulsifying characteristics of CPI.

Processing to improve the sustainability of chickpea as a functional food ingredient

Chickpea is a field crop that is playing an emerging role in the provision of healthy and sustainable plant-based value-added ingredients for the food and nutraceutical industries. This article reviews the characteristics of chickpea (composition, health properties, and techno-functionality) and chickpea grain that influence their use as whole foods or ingredients in formulated food. It covers the exploitation of traditional and emerging processes for the conversion of chickpea into value-added differentiated food ingredients. The influence of processing on the composition, health-promoting properties, and techno-functionality of chickpea is discussed. Opportunities to tailor chickpea ingredients to facilitate their incorporation in traditional food applications and in the expanding plant-based meat alternative and dairy alternative markets are highlighted. The review includes an assessment of the possible uses of by-products of chickpea processing. Recommendations are provided for future research to build a sustainable industry using chickpea as a value-added ingredient. © 2024 Society of Chemical Industry.

Unraveling the Impacts of Germination on the Volatile and Fatty Acid Profile of Intermediate Wheatgrass (Thinopyrum intermedium) Seeds

Intermediate wheatgrass (IWG) is a promising perennial grain explored for mainstream food applications. This study investigated the effects of different germination temperatures (10, 15, and 20 °C) and durations (2, 4, and 6 days) on IWG's volatile and fatty acid (FA) profiles. A method using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was optimized through response surface design to extract the volatile compounds, achieving ideal extraction conditions at 60 °C for 55 min. Multiple headspace extraction (MHE) was used for volatile compound quantification. Fifty-eight compounds were identified and quantified in IWG flour, mainly alcohols, aldehydes, hydrocarbons, terpenes, esters, organic acids, and ketones. The main FAs found were linoleic acid (C18:2), oleic acid (C18:1), palmitic acid (C16:0), and linolenic acid (C18:3). Principal component analysis showed a direct correlation between volatile oxidation products and FA composition. Germination at 15 °C for 6 days led to a reduced presence of aldehydes and alcohols such as nonanal and 1-pentanol. Therefore, optimized germination was successful in reducing the presence of potential off-odor compounds. This study provides valuable insights into the effects of germination on IWG flour, showing a way for its broader use in food applications.

Exploring Volatile Profiles and De-Flavoring Strategies for Enhanced Acceptance of Lentil-Based Foods: A Review

Lentils are marketed as dry seeds, fresh sprouts, flours, protein isolates, and concentrates used as ingredients in many traditional and innovative food products, including dairy and meat analogs. Appreciated for their nutritional and health benefits, lentil ingredients and food products may be affected by off-flavor notes described as "beany", "green", and "grassy", which can limit consumer acceptance. This narrative review delves into the volatile profiles of lentil ingredients and possible de-flavoring strategies, focusing on their effectiveness. Assuming that appropriate storage and processing are conducted, so as to prevent or limit undesired oxidative phenomena, several treatments are available: thermal (pre-cooking, roasting, and drying), non-thermal (high-pressure processing, alcohol washing, pH variation, and addition of adsorbents), and biotechnological (germination and fermentation), all of which are able to reduce the beany flavor. It appears that lentil is less studied than other legumes and more research should be conducted. Innovative technologies with great potential, such as high-pressure processing or the use of adsorbents, have been not been explored in detail or are still totally unexplored for lentil. In parallel, the development of lentil varieties with a low LOX and lipid content, as is currently in progress for soybean and pea, would significantly reduce off-flavor notes.

Physicochemical and chemosensory properties of pomegranate (Punica granatum L.) seeds under various oven-roasting conditions

This study investigated the effects of oven-roasting temperature (160, 180, and 200 ℃) and time (5, 10, 15, and 20 min) on pomegranate seeds. Physicochemical properties, such as color (L*, a*, and b* values), browning index (BI), total phenolic and flavonoid contents, 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity, and chemosensory properties, including taste and volatile compounds, were analyzed. The L* and a* values, and level of sourness, umami, sweetness, and terpenes decreased, whereas the b* value, BI, and level of saltiness, bitterness, furan derivatives, pyrazines, and sulfur-containing compounds, increased with roasting time. The findings of this study showed that the positive roasting conditions for pomegranate seeds were 10-20 min at 160 ℃ and, 5-10 min at 180 ℃. This study is expected to be used as a primary reference for selecting the optimal oven-roasting conditions in which positive effects appear and for developing products utilizing pomegranate seeds.

Identification of volatile and odor-active compounds in pea protein fractions obtained by a modified extraction method using fermentation

This study investigates the aromatic composition of pea albumin and globulin fractions obtained through either fermentation or conventional acidification using hydrochloric acid (control) toward the isoelectric point of pea globulins. Different lactic acid bacteria were used including S. thermophilus (ST), L. plantarum (LP), and their coculture (STLP). The volatile compounds were extracted by solvent-assisted flavor evaporation technique and quantified by gas chromatography-mass spectrometry (GC-MS). Odor-active compounds (OAC) were further characterized by gas chromatography-olfactometry (GC-O). In total, 96 volatile and 36 OACs were identified by GC-MS and GC-O, respectively. The results indicated that the protein fractions obtained by conventional acidification were mainly described by green notes for the presence of different volatile compounds such as hexanal. However, the samples obtained by fermentation had a lower content of these volatile compounds. Moreover, protein fractions obtained by coculture fermentation were described by volatile compounds associated with fruity, floral, and lactic notes. PRACTICAL APPLICATION: The insights from this study on pea protein aroma could find practical use in the food industry to enhance the sensory qualities of plant-based products. By utilizing fermentation methods and specific lactic acid bacteria combinations, manufacturers may produce pea protein with reduced undesirable green notes, offering consumers food options with improved flavors. This research may contribute to the development of plant-based foods that not only provide nutritional benefits but also meet consumer preferences for a more appealing taste profile.

Germination-induced modifications of starch structure, flour-processing characteristics, and in vitro digestive properties in maize

Current research on maize germination suffers from long sampling intervals, and the relationship between the starch structure and the processing properties of flour in maize is still unclear. This study observed the effect of germination on the structure and composition of maize starch and the processing properties of maize flour over a 72 h period using a short interval sampling method. At 36 h, the short-range ordered structure, crystallinity, and enthalpy of starch reached the highest values of 1.02, 34.30%, and 9.90 J/g, respectively. At 72 h, the ratios of rapidly-digested starch (RDS) and slowly-digested starch (SDS) enhanced to 29.37% and 28.97%; the RS content reduced to 35.37%; and the flow properties of the starch were improved. This study enhances the understanding of the effects of germination on the processing properties of maize starch and flour, determines the appropriate application, and recommends the use of germination in the food industry.

Effects of germination time on the structure, functionality, flavour attributes, and in vitro digestibility of green Altamura lentils (Lens culinaris Medik.) flour

There has been an increase in the use of adoptable bioprocessing methods for the development of high-quality leguminous ingredients. The potential use of germinated green Altamura lentils as a food ingredient is closely related to the resulting properties. The objective of this study was to evaluate the impact of three germination times - 0 (C), 24 (G) and 48 (H) hours - on the physicochemical, microstructural, flavour, functional, and nutritional features of lentil flour samples (CF, GF and HF). Lentil flour samples were obtained by grinding both whole green seeds (C) and germinated seeds (G and H), and then sifting them to obtain a particle size < 300 μm. The germinated samples - GF (24 h) and HF (48 h) - exhibited differences (P < 0.05) in the physicochemical and bioactive properties of CF (control). Similarly, compared with those in the control sample, the total starch, amylose and total phenolic contents in the GF and HF samples decreased, while the protein content increased (p < 0.05). A decrease in the presence of intact starch granules was observed via SEM in the germinated samples. The germination time had a significant (P < 0.05) effect on the colour indices, L*, a*, and b* of the samples. Flavour attributes were significantly influenced by the germination time. Overall, a total of 14 (CF) and 17 (GF and HF) aromatic compounds were identified. The technological characteristics of the CF, GF and HF dough samples were studied using a Brabender farinograph. Germination time affects the flour properties, leading to a significant decrease in farinographic parameters such as water absorption (WA), dough development time (DT), and dough stability (DS) and an increase in the degree of dough weakening (DOS). Differential scanning calorimetry was employed to examine the gelatinization transition of the samples. Germination strongly influenced all the thermal properties of the samples. It also had a significant impact on the in vitro starch digestibility, starch fraction and glycaemic index (eGI) of the samples. In particular, the eGI of germinated lentils was lower than that of the CF. In conclusion, the germination time could be a key factor modulating some crucial lentil flour properties.

Modulation of pea protein isolate nanoparticles by interaction with OSA-corn starch: Enhancing the stability of the constructed Pickering emulsions

The impact of particle concentration (0.5-2.5%) on the stability of Pickering emulsions was investigated in this work. Pickering emulsion was prepared using pea protein isolate (PPI)/octenyl succinic anhydrate corn starch (OSA-CS) composite nanoparticles (PPI/OSA-CS) as stabilizers. PPI/OSA-CS was prepared with pH adjustment and ultrasonic treatment, and the particle size was 100.05 ± 0.46 nm. The formation of PPI/OSA-CS through hydrophobic interaction and hydrogen bond was confirmed by Fourier transform infrared spectroscopy, intrinsic fluorescence spectroscopy and dissociation analysis. The results indicated that the emulsion stabilized with composite nanoparticles at 1.5% particle concentration had smaller particle size and better stability than at other concentrations. This could be attributed to the presence of sufficient composite nanoparticles wrapped around the surface of oil droplets. At high temperature (100 °C) and high ionic strength (500 mM), the emulsion remained stable. These results provide a potential method for preparing a novel and stable Pickering emulsion, which could have important applications in various fields.

Alternating current electric field modifies structure and flavor of peanut proteins

The impacts of intensity and treating time of alternating current (AC) electric field (EF) on structure and volatile compounds of peanut protein were investigated for low denaturation. The secondary and tertiary structures, polar and weakly polar volatiles were characterized qualitatively and quantitatively using ultraviolet and fluorescence photospectrometry, free sulfhydryl and disulfide groups determination, and combination of gas chromatography and mass spectrometry. The results showed that the ACEF affected significantly proportions of α-helices, β-sheets, β-turns, and random coils as evidenced by Fourier transform infrared spectrometry. Blue shifts of UV and fluorescence spectra, increased surface hydrophobicity and disulfide bonds could be observed after ACEF treatments. The DB-WAX and DB-5MS columns for the polar and weakly polar volatile compound separation revealed that ACEF caused either disappearance or emerging of volatile compounds. The PCA demonstrated that the two principal components contributed about 70 % or more to the flavor and PLS-DA discriminated 18 key compounds.

The effect of different pre-treatments on unformulated pulse-based milk analogs: physicochemical properties and consumer acceptance

This is the first part of a study on developing pulse-based milk analogs using chickpea, faba bean, and cowpea as raw materials. The objectives of the present study were to determine the processing conditions for pulse-based milk analog production at laboratory-scale and to investigate the effects of some pre-treatments such as dry milling (control), soaking and wet milling, blanching, blanching and dehulling, vacuum, and germination on lipoxygenase (LOX) activity of the raw material and some physicochemical and sensory properties of the final products. Dry milling provided the lowest LOX activity and the highest yield while soaking and wet milling resulted in a substantial increase in LOX activity, lower product yield, and a final product with lower whiteness value, regardless of the pulse type. Germination caused a significant decrease in LOX activity in all pulse types, while milk analogs produced from germinated pulses received the lowest acceptability scores from consumers.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05836-7.

The challenge of breeding for reduced off-flavor in faba bean ingredients

The growing interest in plant protein sources, such as pulses, is driven by the necessity for sustainable food production and climate change mitigation strategies. Faba bean (Vicia faba L.) is a promising protein crop for temperate climates, owing to its remarkable yield potential (up to 8 tonnes ha-1 in favourable growing conditions) and high protein content (~29% dry matter basis). Nevertheless, the adoption of faba bean protein in plant-based products that aim to resemble animal-derived counterparts is hindered by its distinctive taste and aroma, regarded as "off-flavors". In this review, we propose to introduce off-flavor as a trait in breeding programs by identifying molecules involved in sensory perception and defining key breeding targets. We discuss the role of lipid oxidation in producing volatile and non-volatile compounds responsible for the beany aroma and bitter taste, respectively. We further investigate the contribution of saponin, tannin, and other polyphenols to bitterness and astringency. To develop faba bean varieties with diminished off-flavors, we suggest targeting genes to reduce lipid oxidation, such as lipoxygenases (lox) and fatty acid desaturases (fad), and genes involved in phenylpropanoid and saponin biosynthesis, such as zero-tannin (zt), chalcone isomerase (chi), chalcone synthase (chs), β-amyrin (bas1). Additionally, we address potential challenges, including the need for high-throughput phenotyping and possible limitations that could arise during the genetic improvement process. The breeding approach can facilitate the use of faba bean protein in plant-based food such as meat and dairy analogues more extensively, fostering a transition toward more sustainable and climate-resilient diets.

Flavor-food ingredient interactions in fortified or reformulated novel food: Binding behaviors, manipulation strategies, sensory impacts, and future trends in delicious and healthy food design

With consumers gaining prominent awareness of health and well-being, a diverse range of fortified or reformulated novel food is developed to achieve personalized or tailored nutrition using protein, carbohydrates, or fat as building blocks. Flavor property is a critical factor in the acceptability and marketability of fortified or reformulated food. Major food ingredients are able to interact with flavor compounds, leading to a significant change in flavor release from the food matrix and, ultimately, altering flavor perception. Although many efforts have been made to elucidate how food matrix components change flavor binding capacities, the influences on flavor perception and their implications for the innovation of fortified or reformulated novel food have not been systematically summarized up to now. Thus, this review provides detailed knowledge about the binding behaviors of flavors to major food ingredients, as well as their influences on flavor retention, release, and perception. Practical approaches for manipulating these interactions and the resulting flavor quality are also reviewed, from the scope of their intrinsic and extrinsic influencing factors with technologies available, which is helpful for future food innovation. Evaluation of food-ingredient interactions using real food matrices while considering multisensory flavor perception is also prospected, to well motivate food industries to investigate new strategies for tasteful and healthy food design in response to consumers' unwillingness to compromise on flavor for health.

Overview of the Incorporation of Legumes into New Food Options: An Approach on Versatility, Nutritional, Technological, and Sensory Quality

Consumers are more aware and demanding of healthy food options, besides being concerned with environment-friendly consumption. This paper aims to evaluate nutritional, technological, and sensory characteristics of legumes and their products' quality and versatility, considering potential applications in new food options. Legumes are foods that have a recognized nutritional group since they have high protein and fiber content. However, their consumption is still somehow limited for some reasons: in some countries it is not easy to find all the species or cultivars, they need an organization and planning before preparation since they need soaking, and there is the presence of antinutritional factors. Due to the different functionalities of legume proteins, they can be applied to a variety of foods and for different purposes, as grains themselves, aquafaba, extracts, flours, brans, and textured proteins and sprouts. These products have been inserted as ingredients in infant food formulations, gluten-free foods, vegetarian diets, and in hybrid products to reduce food costs as well. Foods such as bread, cakes, cookies, meat analogues, and other baked or cooked products have been elaborated with nutritional, technological and sensory quality. Further development of formulations focused on improving the quality of legume-based products is necessary because of their potential and protein quality.

Sensory profile of pulse-based high moisture meat analogs: A study on the complex effect of germination and extrusion processing

Germination and extrusion are two processes that could affect beany flavors in pulse-based high-moisture meat analogs (HMMAs). This research studied the sensory profile of HMMAs made by protein-rich flours from germinated/ungerminated pea and lentil. Air-classified pulse protein-rich fractions were processed into HMMAs with twin screw extrusion cooking, optimized at 140 °C (zone 5 temperature) and 800 rpm screw speed. Overall, 30 volatile compounds were identified by Gas Chromatography-Mass Spectrometry/Olfactory. Chemometric analysis exhibited that the extrusion markedly (p < 0.05) reduced beany flavor. A synergistic effect of germination and extrusion process was observed, decreasing some beany flavors such as 1-octen-3-ol and 2,4-decadienal, and the overall beany taste. Pea-based HMMAs are suitable for lighter, softer poultry meat, while lentil-based HMMAs are suited for darker, harder livestock meat. Those findings offer novel insights into the regulation of beany flavors, odor notes, color, and taste to improve the sensory quality of HMMAs.

Effects of the use of raw or cooked chickpeas and the sausage cooking time on the quality of a lamb-meat, olive-oil emulsion-type sausage

Reformulation of cooked sausages using high-protein plant-based food such as chickpea as meat extenders and vegetable oils to replace animal fat can be a suitable approach to promote the consumption of smaller portions of meat. The pre-processing of chickpea and the sausage cooking intensity can potentially affect the quality of reformulated sausages. In this study, an emulsion-type sausage made with lamb meat, chickpea and olive oil was prepared in triplicate following three different formulations containing the same targeted levels of protein (8.9%), lipids (21.5%), and starch (2.9%): control sausage (CON; control, without chickpea), and raw (RCP) and cooked chickpea (CCP) sausages (both with 7% chickpea). Sausages were cooked at 85 °C for two heating times (40 min or 80 min) and were analysed for weight loss, emulsion stability, colour, texture, lipid oxidation and volatile composition. Compared to CON sausages, the use of raw chickpea reduced the elasticity and significantly increased lipid oxidation during the sausage-making process resulting in major changes in the volatile composition. The use of previously cooked chickpea, however, resulted in the sausages having greater cooking loss, hardness and chewiness than CON sausages, while there was no difference in lipid oxidation, and differences in volatile compounds were scarce. The reformulation with cooked chickpea could provide a sausage with more similarity to the CON sausage. The extended heating time of 80 min at 85 °C did not significantly affect the quality traits in either CON or reformulated sausages except for a higher cooking loss.

Structural properties of pea proteins (Pisum sativum) for sustainable food matrices

Pea proteins are widely used as a food ingredient, especially in sustainable food formulations. The seed itself consists of many proteins with different structures and properties that determine their structure-forming properties in food matrices, such as emulsions, foams, and gels. This review discusses the current insights into the structuring properties of pea protein mixtures (concentrates, isolates) and the resulting individual fractions (globulins, albumins). The structural molecular features of the proteins found in pea seeds are discussed and based on this information, different structural length scales relevant to foods are reviewed. The main finding of this article is that the different pea proteins are able to form and stabilize structural components found in foods such as air-water and oil-water interfaces, gels, and anisotropic structures. Current research reveals that each individual protein fraction has unique structure-forming properties and that tailored breeding and fractionation processes will be required to optimize these properties. Especially the use of albumins, globulins, and mixed albumin-globulins proved to be useful in specific food structures such as foams, emulsions, and self-coacervation, respectively. These new research findings will transform how pea proteins are processed and being used in novel sustainable food formulations in the future.

Isoelectric point isolation and characterization of proteins from lupine cultivars as influenced by chemical and thermal treatments

Pulses provide a significant nutritional potential for the large proportion of the population in developing countries. Lupine is among the underutilized legume crops for human food in Ethiopia and globally concomitant to its contents of bitter alkaloids. This research was initiated to investigate the effects of soaking lupine seeds of bitter and sweet varieties in water and 2% sodium carbonate (Na₂CO₃) solutions as grain softener on the protein extraction efficiency and its sensory acceptability. It was hypothesized that the soaking treatment results in the removal of characteristic bitterness when coupled with thermal treatment (roasting). The result showed that soaking in Na₂CO₃ significantly increased the protein extraction efficiency (both protein yield and quality (purity)) in the two lupine cultivars. The roasting treatment did not help much. The bitter variety of lupine soaked in Na₂CO₃ with no roasting treatment gave the highest protein yield (39.45%), while the sweet variety soaked in water followed by roasting exhibited the least protein yield (23.25%). The purity of the protein isolates from the lupine samples soaked in 2% Na₂CO₃ followed by roasting was the highest (92.29%). The non-soaked samples of the sweet variety after roasting resulted in the lowest purity (75.05%). The water holding, and oil absorption capacity, as well as the emulsification activity and foaming capacity of the protein isolates were significantly varied for the lupine varieties, and by the soaking and roasting treatments. Higher (314.38%) WHC was recorded for the protein isolates from sweet variety soaked in Na₂CO₃, where the bitter variety, when soaked in 2% Na₂CO₃ without roasting gave protein isolates of higher emulsion and foaming capacities. The research revealed also that soaking of lupine seeds in grain softeners shows a great potential as a pretreatment for enhanced protein extraction and functional desirability (in terms of emulsion and foaming capacities) as well as sensory acceptability and can be recommended for scaling up at industrial level.

Mechanism and application of fermentation to remove beany flavor from plant-based meat analogs: A mini review

Over the past few decades, there has been a noticeable surge in the market of plant-based meat analogs (PBMA). Such popularity stems from their environmentally friendly production procedures as well as their positive health effects. In order to meet the market demand, it is necessary to look for plant protein processing techniques that can help them match the quality of conventional meat protein from the aspects of sensory, quality and functionality. Bean proteins are ideal options for PBMA with their easy accessibility, high nutrient-density and reasonable price. However, the high polyunsaturated lipids content of beans inevitably leads to the unpleasant beany flavor of soy protein products, which severely affects the promotion of soy protein-based PBMA. In order to solve this issue, various methods including bleaching, enzyme and fermentation etc. are developed. Among these, fermentation is widely investigated due to its high efficiency, less harm to the protein matrix, targeted performance and low budget. In addition, proper utilization of microbiome during the fermentation process not only reduces the unpleasant beany flavors, but also enhances the aroma profile of the final product. In this review, we provide a thorough and succinct overview of the mechanism underlying the formation and elimination of beany flavor with associated fermentation process. The pros and cons of typical fermentation technologies for removing beany flavors are discussed in alongside with their application scenarios. Additionally, the variations among different methods are compared in terms of the strains, fermentation condition, target functionality, matrix for application, sensory perception etc.

A comprehensive review on pulse protein fractionation and extraction: processes, functionality, and food applications

The increasing world population requires the production of nutrient-rich foods. Protein is an essential macronutrient for healthy individuals. Interest in using plant proteins in foods has increased in recent years due to their sustainability and nutritional benefits. Dry and wet protein fractionation methods have been developed to increase protein yield, purity, and functional and nutritional qualities. This review explores the recent developments in pretreatments and fractionation processes used for producing pulse protein concentrates and isolates. Functionality differences between pulse proteins obtained from different fractionation methods and the use of fractionated pulse proteins in different food applications are also critically reviewed. Pretreatment methods improve the de-hulling efficiency of seeds prior to fractionation. Research on wet fractionation methods focuses on improving sustainability and functionality of proteins while studies on dry methods focus on increasing protein yield and purity. Hybrid methods produced fractionated proteins with higher yield and purity while also improving protein functionality and process sustainability. Dry and hybrid fractionated proteins have comparable or superior functionalities relative to wet fractionated proteins. Pulse protein ingredients are successfully incorporated into various food formulations with notable changes in their sensory properties. Future studies could focus on optimizing the fractionation process, improving protein concentrate palatability, and optimizing formulations using pulse proteins.

Sustainable plant-based ingredients as wheat flour substitutes in bread making

Bread as a staple food has been predominantly prepared from refined wheat flour. The world's demand for food is rising with increased bread consumption in developing countries where climate conditions are unsuitable for wheat cultivation. This reliance on wheat increases the vulnerability to wheat supply shocks caused by force majeure or man-made events, in addition to negative environmental and health consequences. In this review, we discuss the contribution to the sustainability of food systems by partially replacing wheat flour with various types of plant ingredients in bread making, also known as composite bread. The sustainable sources of non-wheat flours, their example use in bread making and potential health and nutritional benefits are summarized. Non-wheat flours pose techno-functional challenges due to significantly different properties of their proteins compared to wheat gluten, and they often contain off-favor compounds that altogether limit the consumer acceptability of final bread products. Therefore, we detail recent advances in processing strategies to improve the sensory and nutritional profiles of composite bread. A special focus is laid on fermentation, for its accessibility and versatility to apply to different ingredients and scenarios. Finally, we outline research needs that require the synergism between sustainability science, human nutrition, microbiomics and food science.

Applicability of pea ingredients in baked products: Links between formulation, reactivity potential and physicochemical properties

This study aimed to evaluate the applicability of purified pea ingredients (starch and protein isolate) by assessing their potential to form volatile compounds during the different steps of sponge cake development compared to pea flour and wheat flour. While pea flour was highly susceptible to lipid oxidation during batter beating, the combination of purified pea starch and pea protein yielded significantly fewer oxidation markers with known green-beany off-odors. This was due more to the inactivation of lipoxygenase during flour fractionation than to differences in batter structure. However, fractionated ingredients were highly prone to participating in the Maillard reaction and caramelization during baking, leading to a more complex mixture of pyrazines, Strecker aldehydes and furanic compounds with potential malty and roasted notes compared to cakes based on pea flour or wheat flour. These findings confirm that using purified pea fractions can create high-quality products with an attractive composition.

An enzymatic tandem reaction to produce odor-active fatty aldehydes

Abstract

Aldehydes represent a versatile and favored class of flavoring substances. A biocatalytic access to odor-active aldehydes was developed by conversion of fatty acids with two enzymes of the α-dioxygenase pathway. The recombinant enzymes α-dioxygenase (α-DOX) originating from Crocosphaera subtropica and fatty aldehyde dehydrogenase (FALDH) from Vibrio harveyi were heterologously expressed in E. coli, purified, and applied in a coupled (tandem) repetitive reaction. The concept was optimized in terms of number of reaction cycles and production yields. Up to five cycles and aldehyde yields of up to 26% were achieved. Afterward, the approach was applied to sea buckthorn pulp oil as raw material for the enzyme catalyzed production of flavoring/fragrance ingredients based on complex aldehyde mixtures. The most abundant fatty acids in sea buckthorn pulp oil, namely palmitic, palmitoleic, oleic, and linoleic acid, were used as substrates for further biotransformation experiments. Various aldehydes were identified, semi-quantified, and sensorially characterized by means of headspace–solid phase microextraction–gas chromatography–mass spectrometry–olfactometry (HS–SPME–GC–MS–O). Structural validation of unsaturated aldehydes in terms of double-bond positions was performed by multidimensional high-resolution mass spectrometry experiments of their Paternò–Büchi (PB) photoproducts. Retention indices and odor impressions of inter alia (Z,Z)-5,8-tetradecadienal (Z,Z)-6,9-pentadecadienal, (Z)-8-pentadecenal, (Z)-4-tridecenal, (Z)-6-pentadecenal, and (Z)-8-heptadecenal were determined for the first time.

Key points

• Coupled reaction of Csα-DOX and VhFALDH yields chain-shortened fatty aldehydes.

• Odors of several Z-unsaturated fatty aldehydes are described for the first time.

• Potential for industrial production of aldehyde-based odorants from natural sources.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00253-022-12134-3.

The Impact of Dehulling and Germination on the Physiochemical, Protein Solubility and Water and Oil Holding Capacities of Yellow Eye Bean (Phaseolus vulgaris L.) Protein Concentrates

Pulse varieties including Yellow Eye (YE) beans (Phaseolus vulgaris L.) are a rich source of protein (~26.5%) that can be utilized to create value-added protein concentrates. Pre-treatments including dehulling and germination have been shown to be effective at improving the nutritional and functional properties of extracted protein concentrates. However, the composition and functionality of these protein concentrates can vary depending on the pre-treatments and the method of extraction used (salt vs. alkaline). Furthermore, little is known about the impact of combining these different processing methods on the properties of YE bean protein concentrates. The objective of this study was to evaluate how germination and dehulling pre-treatments individually and when combined influence protein extraction efficiency, physiochemical properties (surface hydrophobicity and intrinsic fluorescence), and the functionality (solubility, oil and water holding capacities) of salt and alkaline extracted protein concentrates. Compared to the salt extracted concentrates, the alkaline protein concentrates exhibited higher protein recovery yields (16–23% vs. 43–56%) respectively. Conversely, the salt extracted protein concentrates exhibited superior functional properties as observed by improved water holding capacities and less variation in their solubilities at different pH values (4 to 10). When the pre-treatments were combined, the salt extracted concentrates exhibited improved extraction efficiencies and improved hydrophobicity and intrinsic fluorescence, whereas the opposite trend was observed in the alkaline protein concentrates. These observations were attributed to differences in the protein content and composition of the salt vs. alkaline protein concentrates. Overall, these findings suggest that dehulling and germination are potential processing methods that may be used to improve the physiochemical characteristics of salt extracted protein concentrates from yellow eye beans. Future research may investigate the potential application of these ingredients in different food formulations.

Flavor challenges in extruded plant-based meat alternatives: A review

Demand for plant-based meat alternatives has increased in recent years due to concerns about health, ethics, the environment, and animal welfare. Nevertheless, the market share of plant-based meat alternatives must increase significantly if they are to support sustainable food production and consumption. Flavor is an important limiting factor of the acceptability and marketability of plant-based meat alternatives. Undesirable chemosensory perceptions, such as a beany flavor, bitter taste, and astringency, are often associated with plant proteins and products that use them. This study reviewed 276 articles to answer the following five research questions: (1) What are the volatile and nonvolatile compounds responsible for off-flavors? (2) What are the mechanisms by which these flavor compounds are generated? (3) What is the influence of thermal extrusion cooking (the primary structuring technique to transform plant proteins into fibrous products that resemble meat in texture) on the flavor characteristics of plant proteins? (4) What techniques are used in measuring the flavor properties of plant-based proteins and products? (5) What strategies can be used to reduce off-flavors and improve the sensory appeal of plant-based meat alternatives? This article comprehensively discusses, for the first time, the flavor issues of plant-based meat alternatives and the technologies available to improve flavor and, ultimately, acceptability.

Application of emerging technologies to obtain legume protein isolates with improved techno-functional properties and health effects

Current demand of consumers for healthy and sustainable food products has led the industry to search for different sources of plant protein isolates and concentrates. Legumes represent an excellent nonanimal protein source with high-protein content. Legume species are distributed in a wide range of ecological conditions, including regions with drought conditions, making them a sustainable crop in a context of global warming. However, their use as human food is limited by the presence of antinutritional factors, such as protease inhibitors, lectins, phytates, and alkaloids, which have adverse nutritional effects. Antitechnological factors, such as fiber, tannins, and lipids, can affect the purity and protein extraction yield. Although most are removed or reduced during alkaline solubilization and isoelectric precipitation processes, some remain in the resulting protein isolates. Selection of appropriate legume genotypes and different emerging and sustainable facilitating technologies, such as high-power ultrasound, pulsed electric fields, high hydrostatic pressure, microwave, and supercritical fluids, can be applied to increase the removal of unwanted compounds. Some technologies can be used to increase protein yield. The technologies can also modify protein structure to improve digestibility, reduce allergenicity, and tune technological properties. This review summarizes recent findings regarding the use of emerging technologies to obtain high-purity protein isolates and the effects on techno-functional properties and health.

Sensory descriptors for pulses and pulse-derived ingredients: Toward a standardized lexicon and sensory wheel

The organoleptic quality of pulses and their derived ingredients is fundamental in human utilization and evolution of food. However, the widespread use of pulses is hindered by their inherent sensorial aspects, which are regarded as atypical by the consumers who are unfamiliar to them. In most studies involving sensory assessment of pulses and pulse-ingredients using classical descriptive analysis methods, assessors establish their own lexica. This review is a synthesis of descriptive terms by which sensations emanating from pea, chickpea, lentil, faba bean, dry bean, bambara groundnut, lupin, pigeon pea and cowpea, and their derived ingredients have been described in the literature. Studies involving sensory assessment of processed whole seeds, slurries of raw flour, slurries of protein extracted from raw flour, and food products containing components of pulses were considered. The terms are categorized into those denoting basic taste, aroma, flavor, and trigeminal sensations. Bitterness is the most widely perceived basic taste. Beany, which is broad and complex with subcharacter notes, is predominantly used to describe aroma and flavor. The frequency of use of the collated terms in the reviewed studies was used to establish a sensory wheel. Inconsistency in the use of descriptive terms in the literature necessitates establishment of a standard lexicon that can be applied in both classical and increasingly popular rapid descriptive methods (e.g., check-all-that-apply) throughout the pulse value chain. This review is timely considering the dominance of pulses in plant-based foods and their increasing appeal to the food industry.

Radio frequency heating of green peas (Pisum sativum L.): The improvement of heating uniformity and its dry blanching effect

A radio frequency (RF) heating system was used to process green peas and a rotating system was introduced to improve heating rate and heating uniformity. Results revealed that rotation treatment accelerated heating rate effectively and improved heating uniformity index significantly (p < 0.05) from 0.175 (0 rpm, 55°C) to 0.029 (60 rpm, 55°C). After being treated with RF and traditional hot water blanching at 85°C, the residual lipoxygenase activities of green peas were 1.90 ± 0.71% and 35.51 ± 5.25%, respectively, confirming RF possessed better blanching efficiency. Meanwhile, weight loss, electrolyte leakage rate, color, and texture of green peas all had significant changes (p < 0.05) through RF heating. PRACTICAL APPLICATION: A rotation device can effectively improve heating uniformity of RF electromagnetic heating. The rotation device could be expanded or further developed into continuous feeding conveying device for industrial production.

Aroma of peas, its constituents and reduction strategies - Effects from breeding to processing

Peas as an alternative protein source have attracted a great deal of interest from the food industry and consumers in recent years. However, pea proteins usually do not taste neutral and exhibit a distinct flavor, often characterized as "beany". This is usually contrasted by the food industry's desire for sensory neutral protein sources. In this review, we highlight the current state of knowledge about the aroma of peas and its changes along the pea value chain. Possible causes and origins, and approaches to reduce or eliminate the aroma constituents are presented. Fermentative methods were identified as interesting to mitigate undesirable off-flavors. Major potential has also been discussed for breeding, as there appears to be a considerable leverage at this point in the value chain: a reduction of plant-derived flavors, precursors, or substrates involved in off-flavor evolution could prevent the need for expensive removal later.

Effect of Revtech thermal processing on volatile organic compounds and chemical characteristics of split yellow pea (Pisum sativum L.) flour

Yellow pea (Pisumsativum L.) is an economically rich source of nutrients with health-promoting effects. However, the consumption of pea ingredients is minimal due to their off-flavor characteristics. The present study investigated the effect of Revtech heat treatment on the chemical profile and volatile compounds in split yellow pea flour. Revtech treatment (RT) was applied at 140°C with a residence time of 4 min in dry condition (RT 0%) and in the presence of 10% steam (RT 10%). Both thermal treatments resulted in a significant reduction (p < 0.05) in lipoxygenase activity and the concentration of key beany-related odors such as heptanal, (E)-2-heptenal, 1-octen-3-ol, octanal, and (E)-2-octenal. In addition, RT 10% resulted in a significant reduction in pentanal, 1-penten-3-ol, hexanal, and 1-hexanol compared to untreated flour. The content of known precursors of lipoxygenase such as linoleic and linolenic acids was found in higher concentrations in heat-treated flours, indicating the efficacy of Revtech technology in minimizing the degradation of polyunsaturated fatty acids. No significant changes in the amino acid composition or the 29 selected phenolic compounds in pea flours were observed with Revtech processing except for two compounds, caffeic acid and gallocatechin, which were found at higher concentrations in RT 0%. PRACTICAL APPLICATION: Thermal processing of split yellow pea flours at 140°C using Revtech technology successfully decreased the concentrations of volatile compounds responsible for beany off-flavor while improving the nutritional quality of studied yellow pea flours. These results provide valuable information to the food industry for developing novel pulse-based products with enhanced sensory characteristics.

Simple method for fabrication of high internal phase emulsions solely using novel pea protein isolate nanoparticles: Stability of ionic strength and temperature

The oil-in-water high internal phase emulsions (HIPEs) could be stabilized by pea protein isolate nanoparticles (PPINs) induced by potassium metabisulfite (K₂S₂O₅). Confocal laser scanning microscope proved that PPINs were attached on the oil-water interface, indicating characteristic of Pickering HIPEs. The HIPEs stabilized by PPINs of higher concentration had smaller droplet size, better storage and centrifugal stability than that of PPINs of low concentration because there were enough particles to constitute the thick interface film. The storage modulus was higher than loss modulus indicating that HIPEs exhibited gel-like structure. At different temperatures and ionic strengths, HIPEs exhibited flocculation but still maintained a stable gel-like structure. The strain curve of HIPEs showed Type III nonlinear behavior due to the flocculation of emulsion droplets. HIPEs stabilized by PPINs might be a potential alternative to partially hydrogenated oils to reduce intake of trans fatty acids.

Advanced and feasible pulses processing technologies for Ethiopia to achieve better economic and nutritional goals: A review

Background

Pulses are the dried seeds of the Leguminosae family that serve as cheaper proteins, particularly in developing countries. They contain proteins ranging 20-25%. Pulses play important roles in the farming systems and in the diets of poor people. They are ideal crops for simultaneously achieving three key developmental goals: reducing poverty, improving human health, and enhancing ecosystem sustainability. The year 2016 was declared as the year of pulses by the United Nations. These growing global attentions given to legumes has resulted in increasing their nutritional and economic desirability.

Objectives

This review presents the potential of pulses processing in Ethiopia for enhanced nutritional and economic outcomes. Pulses are important foods and export commodity in Ethiopia, which are exported in unprocessed form, fetching low returns.

Data and discussions

There are advanced but simple pulses processing technologies that include concentrating or isolation of proteins for nutritional and other uses. Pin milling of legumes and air classification of the flour helps to obtain protein concentrate of 60-75% purity. Protein isolation by alkaline extraction and isoelectric precipitation results in proteins of 90-95% purity. Legume proteins are mainly globulins and albumins that are nutritionally of great quality. The protein products are being texturized by thermal and mechanical means to make meat analogues, substitutes and extenders.

Summary and conclusion

Ethiopia being one of the significant legume producers, can benefit from this growing market by adopting the processing technologies and exporting premium quality plant proteins. This help Ethiopia satisfy domestic protein needs for child nutrition. This review summarizes the potentials for developing pulses processing technologies in Ethiopia for better economic and nutritional benefits.

New Insights on Volatile Components of Vanilla planifolia Cultivated in Taiwan

Vanilla (Vanilla planifolia) is a precious natural flavoring that is commonly used throughout the world. In the past, all vanilla used in Taiwan was imported; however, recent breakthroughs in cultivation and processing technology have allowed Taiwan to produce its own supply of vanilla. In this study, headspace solid-phase microextraction (HS-SPME) combined with GC-FID and GC-MS was used to analyze the volatile components of vanilla from different origins produced in Taiwan under different cultivation and processing conditions. The results of our study revealed that when comparing different harvest maturities, the composition diversity and total volatile content were both higher when the pods were matured for more than 38 weeks. When comparing different killing conditions, we observed that the highest vanillin percentage was present after vanilla pods were killed three times in 65 °C treatments for 1 min each. From the experiment examining the addition of different strains, the PCA results revealed that the volatiles of vanilla that was processed with Dekkera bruxellensis and Bacillus subtilis was clearly distinguished from which obtained by processing with the other strains. Vanilla processed with B. subtilis contained 2-ethyl-1-hexanol, and this was not detected in other vanillas. Finally, when comparing the vanillin percentage from seven different regions in Taiwan, vanilla percentage from Taitung and Taoyuan Longtan were the highest.

Toward a comprehensive understanding of ultracentrifugal milling on the physicochemical properties and aromatic profile of yellow pea flour

Yellow pea (Pisum sativum L., YP) grain is generally milled into flour for further processing or direct consumption. However, the comprehensive relationship between milling configurations and YP flour properties remains unclear. The aim of this study is to investigate the effect of configurations (screen aperture size and rotor speed) of ultracentrifugal mill on the physicochemical properties and aromatic profiles of YP flours. Starch damage, morphology, particle size distribution, pasting, thermal property, and aromatic profiles of YP flours were studied. Results show that starch damage increased significantly as the screen aperture size decreased. The YP flour produced with a 500 µm aperture screen had the most stable pasting and thermal properties. With untargeted metabolomic approaches, 2-ethyl-1-hexanol could potentially be applied as an aroma maker to distinguish if an excessive milling or inappropriate configurations of ultracentrifugal mill are applied. This work has furnished fundamentals for the milling and application of YP flour.

Blanching effects of radio frequency heating on enzyme inactivation, physiochemical properties of green peas (Pisum sativum L.) and the underlying mechanism in relation to cellular microstructure

Fresh green peas require blanching to terminate enzymatic reaction induced quality deterioration before frozen storage. Radio frequency (RF) heating is a novel way of dry blanching for fruits and vegetables with high processing efficiency. In this study, blanching effects of RF heating on relative activities of lipoxygenase (LOX) and peroxidase (POD), physiochemical properties as well as cellular morphology changes of green peas were investigated. Results showed relative activities of pea LOX and POD reduced to 0.90 ± 0.78% and 1.10 ± 0.71%, respectively at 85 °C by RF heating with an electrode gap 105 mm. Weight loss, color, texture and electrolyte leakage of peas changed significantly with increasing temperature (60-85 °C). Ascorbic acid, chlorophyll and mineral contents had different loss after RF processing and long term heating at 115 mm exacerbated the loss of nutrients. Microstructure features showed the deconstruction of pea cell well and starch granule gelatinization.

Perspectives on the Use of Germinated Legumes in the Bread Making Process, A Review

Nowadays, it may be noticed that there is an increased interest in using germinated seeds in the daily diet. This high interest is due to the fact that in a germinated form, the seeds are highly improved from a nutritional point of view with multiple benefits for the human body. The purpose of this review was to update the studies made on the possibilities of using different types of germinated legume seeds (such as lentil, chickpea, soybean, lupin, bean) in order to obtain bakery products of good quality. This review highlights the aspects related to the germination process of the seeds, the benefits of the germination process on the seeds from a nutritional point of view, and the effects of the addition of flour from germinated seeds on the rheological properties of the wheat flour dough, but also on the physico–chemical and sensory characteristics of the bakery products obtained. All these changes on the bread making process and bread quality depend on the level and type of legume seed subjected to the germination process which are incorporated in wheat flour.