Insights into formation, detection and removal of the beany flavor in soybean protein

Exploring the flavor changes in mung bean flour through Lactobacillus fermentation: insights from volatile compounds and non-targeted metabolomics analysis

BACKGROUND

Mung beans are highly nutritious but their leguminous flavor limits their development. Lactic acid bacteria (LAB) fermentation can decrease unwanted bean flavors in legumes and enhance their flavor. This study examined the influence of Lactobacillus fermentation on the flavor characteristics of mung bean flour (MBF) using volatile compounds and non-targeted metabolomics.

RESULTS

Lactobacillus plantarum LP90, Lactobacillus casei LC89, and Lactobacillus acidophilus LA85 eliminated 61.37%, 48.29%, and 43.73%, respectively, of the primary bean odor aldehydes from MBF. The relative odor activity value (ROAV) results showed that fermented mung bean flour (FMBF) included volatile chemicals that contributed to fruity, flowery, and milky aromas. These compounds included ethyl acetate, hexyl formate, 3-hydroxy-2-butanone, and 2,3-butanedione. The levels of amino acids with a fresh sweet flavor increased significantly by 93.89, 49.40, and 35.27% in LP90, LC89, and LA85, respectively. A total of 49 up-regulated and 13 down-regulated significantly differential metabolites were annotated, and ten metabolic pathways were screened for contributing to the flavor. The correlation between important volatile compounds and non-volatile substances relies on two primary metabolic pathways: the citric acid cycle pathway and the amino acid metabolic system.

CONCLUSION

The flavor of MBF was enhanced strongly by the process of Lactobacillus fermentation, with LP90 having the most notable impact. These results serve as a reference for identifying the flavor of FMBF. © 2024 Society of Chemical Industry.

Genomic and metabolomic analysis of Latilactobacillus sakei DCF0720 for black soybean yogurt fermentation

Lactic acid bacteria are commonly used in plant-based fermentation to reduce off-flavor and improve sensory characteristics. However, there have been few studies on Latilactobacillus sakei for plant-based yogurt fermentation and, particularly, its metabolic features at the genomic level remain unclear. This study aims to analyze the fermentation characteristics of the L. sakei DCF0720 strain and compare genetics and metabolic relations. For this, DCF0720 was used to ferment the black soybean milk and conduct the physicochemical analysis and sensory test. The genomic and metabolic analyses were performed by complete genome sequencing and 500 MHz 1H NMR, respectively. As a result, DCF0720 exhibited enhanced fermentation performance and sensory evaluations at 37 °C compared to 30 °C, which is generally recognized as the optimal growth temperature for most L. sakei strains. It also produced flavor enhancing volatile compounds such as acetoin and hydroxyacetone, possessing all three key genes for acetoin biosynthesis. DCF0720 lacks 2,3-butanediol dehydrogenase, which leads to the inhibition of acetoin production. DCF0720 possesses a complete pathway to utilize primary black soybean carbon sources such as sucrose, raffinose, and stachyose. DCF0720 also possesses genes for the GH28 family, including the key enzymes in the hydrolysis of pectin substances, which means eliminating the main soybean nonstarch polysaccharides. This study demonstrates that DCF0720 is a suitable starter for plant-based yogurt fermentation, providing a better understanding of fermentation conditions with genetic and metabolic features for black soybean yogurt. Various carbon source utilization abilities with depth metabolic pathway analysis provide that DCF0720 can be employed to develop enhanced starter cultures for black soybean yogurt and diverse plant-based yogurts.

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.

Effect of Corynebacterium glutamicum Fermentation on the Volatile Flavors of the Enzymatic Hydrolysate of Soybean Protein Isolate

This study focused on improving the flavor quality of seasonings, and enzymatic hydrolysis of soybean protein isolate (SPI) seasoning via traditional technology may lead to undesirable flavors. Herein, we aimed to develop a new type of SPI seasoning through microbial fermentation to improve its flavor quality. The effect of Corynebacterium glutamicum fermentation on the flavoring compounds of seasonings in SPI enzymatic hydrolysate was examined. Sensory evaluation showed that the SPI seasoning had mainly aromatic and roasted flavor, and the response signals of S18 (aromatic compounds), S24 (alcohols and aldehydes), and S25 (esters and ketones) sensors of the electronic nose differed significantly. Overall, 91 volatile compounds were identified via gas chromatography-mass spectrometry. SPI seasonings contained a higher number of alcohols, ketones, aromatics, and heterocyclic compounds than traditional seasonings, which had stronger cheese, fatty, and roasted aromas. According to the relative odor activity value (ROAV) analysis, n-pentylpyrzine, 2,6-dimethylpyrazine, and tetramethylpyrazine are the key flavoring compounds (ROAV ≥ 1) of SPI seasoning, which may impart a unique roasted and meaty aroma. Therefore, the fermentation of SPI enzymatic hydrolysate with C. glutamicum may improve the flavor quality of its products, providing a new method for the development and production of new seasoning products.

Advancements in plant based meat analogs enhancing sensory and nutritional attributes

The burgeoning demand for plant-based meat analogs (PBMAs) stems from environmental, health, and ethical concerns, yet replicating the sensory attributes of animal meat remains challenging. This comprehensive review explores recent innovations in PBMA ingredients and methodologies, emphasizing advancements in texture, flavor, and nutritional profiles. It chronicles the transition from soy-based first-generation products to more diversified second- and third-generation PBMAs, showcasing the utilization of various plant proteins and advanced processing techniques to enrich sensory experiences. The review underscores the crucial role of proteins, polysaccharides, and fats in mimicking meat's texture and flavor and emphasizes research on new plant-based sources to improve product quality. Addressing challenges like production costs, taste, texture, and nutritional adequacy is vital for enhancing consumer acceptance and fostering a more sustainable food system.

Recent trends in design of healthier fat replacers: Type, replacement mechanism, sensory evaluation method and consumer acceptance

In recent years, with the increasing awareness of consumers about the relationship between excessive fat intake and chronic diseases, such as obesity, heart disease, diabetes, etc., the demand for low-fat foods has increased year by year. However, a simple reduction of fat content in food will cause changes in physical and chemical properties, physiological properties, and sensory properties of food. Therefore, developing high-quality fat replacers to replace natural fats has become an emerging trend, and it is still a technical challenge to completely simulate the special function of natural fat in low-fat foods. This review aims to provide an overview of development trends of fat replacers, and the different types of fat replacers, the potential fat replacement mechanisms, sensory evaluation methods, and their consumer acceptance are discussed and compared, which may provide a theoretical guidance to produce fat replacers and develop more healthy low-fat products favored by consumers.

A Comprehensive Review on Harnessing Soy Proteins in the Manufacture of Healthy Foods through Extrusion

The global development of livestock production systems, accelerated by the growing demand for animal products, has greatly contributed to land-use change, greenhouse gas emissions, and pollution of the local environment. Further, excessive consumption of animal products has been linked with cardiovascular diseases, digestive system diseases, diabetes, and cancer. On the other hand, snacks, pasta, and bread available on the market are made from wheat, fat, salt, and sugar, which contribute to the risk of cardiovascular diseases. To counter these issues, a range of plant protein-based food products have been developed using different processing techniques, such as extrusion. Given the easy scalability, low cost of extrusion technology, and health benefits of soy proteins, this review focuses on the extrusion of soy protein and the potential application of soy protein-based extrudates in the manufacture of healthy, nutritious, and sustainable meat analogs, snacks, pasta products, and breakfast cereals. This review discusses the addition of soy protein to reformulate hypercaloric foods through extrusion technology. It also explores physical and chemical changes of soy proteins/soy protein blends during low and high moisture extrusion. Hydrogen bonds, disulfide bonds, and hydrophobic interactions influence the properties of the extrudates. Adding soy protein to snacks, pasta, breakfast cereals, and meat analogs affects their nutritional value, physicochemical properties, and sensory characteristics. The use of soy proteins in the production of low-calorie food could be an excellent opportunity for the future development of the soybean processing industry.

Soybean fermentation: Microbial ecology and starter culture technology

Fermented soybean products, including Soya sauce, Tempeh, Miso, and Natto have been consumed for decades, mainly in Asian countries. Beans are processed using either solid-state fermentation, submerged fermentation, or a sequential of both methods. Traditional ways are still used to conduct the fermentation processes, which, depending on the fermented products, might take a few days or even years to complete. Diverse microorganisms were detected during fermentation in various processes with Bacillus species or filamentous fungi being the two main dominant functional groups. Microbial activities were essential to increase the bean's digestibility, nutritional value, and sensory quality, as well as lower its antinutritive factors. The scientific understanding of fermentation microbial communities, their enzymes, and their metabolic activities, however, still requires further development. The use of a starter culture is crucial, to control the fermentation process and ensure product consistency. A broad understanding of the spontaneous fermentation ecology, biochemistry, and the current starter culture technology is essential to facilitate further improvement and meet the needs of the current extending and sustainable economy. This review covers what is currently known about these aspects and reveals the limited available information, along with the possible directions for future starter culture design in soybean fermentation.

Analyzing changes in volatile flavor compounds of soy protein isolate during ultrasonic-thermal synergistic treatments using electronic nose and HS-SPME-GC-MS combined with chemometrics

The beany flavor of soy protein isolate (SPI) creates barriers to their application in food processing. This study investigated the effect of ultrasonic-thermal synergistic treatments, combined with vacuum degassing, on the removal of volatile compounds from SPI. The results revealed that ultrasonic-thermal synergistic treatments altered protein secondary structure and increased fluorescence intensity and surface hydrophobicity, which affected the flavor-binding ability of protein, resulting in reduced electronic nose sensor response values. At synergistic treatment (350 W, 120 ℃ and 150 s), the content of hexanal, (E)-2-hexenal, and 1-octen-3-ol reduced by 70.60 %, 95.60 % and 61.23 %. (E)-2-nonenal and 2-pentylfuran were not detected. Chemometric analysis indicated significant flavor differences between control and treated SPI. Furthermore, α-helix, β-sheet, β-turn, and surface hydrophobicity highly correlated with volatile compounds through correlation analysis, indicating that altered protein structure affected interactions with volatile compounds. The study reduced beany flavor and further expanded the range of applications of plant protein in food industry.

Reduction of Beany Flavor and Improvement of Nutritional Quality in Fermented Pea Milk: Based on Novel Bifidobacterium animalis subsp. lactis 80

Peas (Pisum sativum L.) serve as a significant source of plant-based protein, garnering consumer attention due to their high nutritional value and non-GMO modified nature; however, the beany flavor limits its applicability. In this study, the effects of Bifidobacterium animalis subsp. Lactis 80 (Bla80) fermentation on the physicochemical characteristics, particle size distribution, rheological properties, and volatile flavor compounds of pea milk was investigated. After fermentation by Bla80, the pH of pea milk decreased from 6.64 ± 0.01 to 5.14 ± 0.01, and the (D4,3) distribution decreased from 142.4 ± 0.47 μm to 122.7 ± 0.55 μm. In addition, Lactic acid bacteria (LAB) fermentation significantly reduced the particle size distribution of pea milk, which was conducive to improving the taste of pea milk and also indicated that Bla80 had the probiotic potential of utilizing pea milk as a fermentation substrate. According to GC-MS analysis, 64 volatile compounds were identified in fermented pea milk and included aldehydes, alcohols, esters, ketones, acids, and furans. Specifically, aldehydes in treated samples decreased by 27.36% compared to untreated samples, while esters, ketones, and alcohols increased by 11.07%, 10.96%, and 5.19%, respectively. These results demonstrated that Bla80 fermentation can significantly decrease the unpleasant beany flavor, such as aldehydes and furans, and increase fruity or floral aromas in treated pea milk. Therefore, Bla80 fermentation provides a new method to improve physicochemical properties and consumer acceptance of fermented pea milk, eliminating undesirable aromas for the application of pea lactic acid bacteria beverage.

Characterization of odor profiles of pea milk varieties and identification of key odor-active compounds by molecular sensory science approaches using soybean milk as a reference

This study investigated the odor profiles of four pea milk varieties based on sensory evaluation, electronic nose (E-nose), and gas chromatography-mass spectrometry (GC-MS) with soybean milk as a reference. Compared to soybean milk, pea milk exhibited lower intensity of beany, oil-oxidation, and mushroom flavors as well as higher intensity of grassy/green and earthy flavors. ZW.6 pea milk was selected for further identification of key odor-active compounds using molecular sensory science approaches. Using headspace solid phase microextraction (HS-SPME), solvent-assisted flavor evaporation (SAFE), and dynamic headspace sampling (DHS) combined with comprehensive gas chromatography-olfactometry-mass spectrometry (GC × GC-O-MS), 102 odor-active compounds were detected in ZW.6 pea milk. Among these, 19 compounds exhibiting high flavor dilution (FD) factors were accurately quantitated. Ten key odor-active compounds were ultimately identified through aroma recombination and omission experiment. Aldehydes and alcohols significantly contribute to the odor profile of pea milk.

Technological challenges and future perspectives of plant-based meat analogues: From the viewpoint of proteins

The global demand for high-quality animal protein faces challenges, prompting a surge in interest in plant-based meat analogues (PBMA). PBMA have emerged as a promising solution, although they encounter technological obstacles. This review discusses the technological challenges faced by PBMA from the viewpoint of plant proteins, emphasizing textural, flavor, color, and nutritional aspects. Texturally, PBMA confront issues, such as deficient fibrous structure, chewiness, and juiciness. Addressing meat flavor and mitigating beany flavor in plant protein are imperative. Furthermore, achieving a distinctive red or pink meat color remains a challenge. Plant proteins exhibit a lower content of essential amino acids. Future research directions encompass (1) shaping myofibril fibrous structures through innovative processing; (2) effectively eliminating the beany flavor; (3) developing biotechnological methodologies for leghemoglobin and plant-derived pigments; (4) optimizing amino acid composition to augment the nutritional profiles. These advancements are crucial for utilization of plant proteins in development of high-quality PBMA.

Plant-Based Proteins, Peptides and Amino Acids in Food Products Dedicated for Sportspeople-A Narrative Review of the Literature

Plant proteins are increasingly seen as critical nutrient sources for both amateur and professional athletes. The aim of the presented study was to review the inventions and experimental articles referring to the application of plant-based proteins, peptides and amino acids in food products dedicated to sportspeople and published in the period 2014-2023. The literature search was conducted according to PRISMA statementsacross several key databases, including Scopus and ISI Web of Science. Altogether, 106 patents and 35 original articles were found. The survey of patents and inventions described in the articles showed the use of 52 taxa (mainly annual herbaceous plants), creating edible seeds and representing mainly the families Fabaceae and Poaceae. The majority of inventions were developed by research teams numbering from two to five scientists, affiliated in China, The United States of America and Japan. The greatest number of inventions applied plant-based proteins (especially protein isolates), declared the nutritional activity and were prepared in liquid or solid consistency. According to the reviewed studies, the intake of soybean and potato proteins might provide better results than animal-based protein (excluding resistance training), whereas the consumption of pea and rice protein does not possess any unique anabolic properties over whey protein. The analysis of other investigations demonstrated the varied acceptability and consumption of food products, while the high rating of the tested food products presented in four articles seems to be an effect of their sensual values, as well as other elements, such as production method, health benefits and cost-effectiveness. Considering the great potential of useful plant species, it might be concluded that future investigations focusing on searching for novel plant protein sources, suitable for the preparation of food products dedicated to amateur and professional sportspeople, remain of interest.

Investigation into the Sensory Properties of Plant-Based Eggs, as Well as Acceptance, Emotional Response, and Use

Consumers have become interested in plant-based alternatives to animal-based products. One of the under-studied alternatives is plant-based eggs (PBEs). This research investigated PBEs relative to conventional eggs and tofu scramble-another plant-based alternative. Firstly, participants (n = 93) completed a word association task asking them about PBEs. Participants then evaluated the different food samples using hedonic scales, check-all-that-apply (CATA), and temporal check-all-that-apply (TCATA), as well as identified their emotional response and proposed use for PBEs. Participants were interested in plant-based alternatives, including PBEs, but they were concerned about the sensory properties. When they evaluated the different samples, the flavour and texture of the PBEs were disliked in comparison to the eggs. This result may be due to the beany, bitterness, and off-flavour attributes associated with the PBEs. Participants also associated the PBEs with negative emotions. The liking of tofu scramble was not significantly different from the eggs, and the eggs and tofu scramble were mainly associated with positive emotions. During the TCATA evaluation, the participants focused on the flavour attributes of PBEs, while their evaluation of the eggs was dominated by the textural attributes. Whether following a plant-based diet or not, consumers are interested in PBEs, but the sensory properties of PBEs need to be improved before they are willing to adopt them into their diet. This study is one of the first to evaluate the sensory properties of PBEs, as well as consumers' emotional response to them and their attitudes about PBEs.

Flavor of extruded meat analogs: A review on composition, influencing factors, and analytical techniques

Meat analogs are anticipated to alleviate environmental and animal welfare concerns as the demand for meat rises. High moisture extrusion is commonly employed to produce meat analogs, and its flavor could influence consumers' choice. To improve the development and market demand of extruded meat analogs, flavor precursors and natural spices have been used in high moisture extrusion process to directly improve the flavor profile of extruded meat analogs. Although there have been many studies on the flavor of high moisture extruded meat analogs, flavor composition and influencing factors have not been summarized. Thus, this review systematically provides the main pleasant and unpleasant flavor-active substances with 79 compounds, as well as descriptive the influence of flavor-active compounds, chemical reactions (such as lipid oxidation and the Maillard reaction), and fiber structure formation (based on extrusion process, extrusion parameters, and raw materials) on flavor of extruded meat analogs. Flavor evaluation of extruded meat analogs will toward multiple assessment methods to fully and directly characterize the flavor of extruded meat analogs, especially machine learning techniques may help to predict and regulate the flavor characteristics of extruded meat analogs.

Use of Pea Proteins in High-Moisture Meat Analogs: Physicochemical Properties of Raw Formulations and Their Texturization Using Extrusion

A new form of plant-based meat, known as 'high-moisture meat analogs' (HMMAs), is captivating the market because of its ability to mimic fresh, animal muscle meat. Utilizing pea protein in the formulation of HMMAs provides unique labeling opportunities, as peas are both "non-GMO" and low allergen. However, many of the commercial pea protein isolate (PPI) types differ in functionality, causing variation in product quality. Additionally, PPI inclusion has a major impact on final product texture. To understand the collective impact of these variables, two studies were completed. The first study compared four PPI types while the second study assessed differences in PPI inclusion amount (30-60%). Both studies were performed on a Wenger TX-52 extruder, equipped with a long-barrel cooling die. Rapid-visco analysis (RVA) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated differences in protein solubility among the different PPI types. In general, lower protein solubility led to better product quality, based on visual evaluation. Cutting strength and texture profile analysis showed increasing PPI inclusion from 30-60% led to significantly higher product hardness (14,160-16,885 g) and toughness (36,690-46,195 g. s). PPI4 led to lower product toughness (26,110 and 33,725 g. s), compared to the other PPIs (44,620-60,965 g. s). Heat gelling capacity of PPI4 was also highest among PPI types, by way of least gelation concentration (LGC) and RVA. When compared against animal meat, using more PPI (50-60%) better mimicked the overall texture and firmness of beef steak and pork chops, while less PPI better represented a softer product like chicken breast. In summary, protein content and also functionality such as cold water solubility and heat gelation dictated texturization and final product quality. High cold water solubility and poor heat gelation properties led to excessive protein cross linking and thicker yet less laminated shell or surface layer. This led to lower cutting firmness and toughness, and less than desirable product texture as compared to animal meat benchmarks. On the other hand, pea proteins with less cold water solubility and higher propensity for heat gelation led to products with more laminated surface layer, and higher cutting test and texture profile analysis response. These relationships will be useful for plant-based meat manufacturers to better tailor their products and choice of ingredients.

Textured soy protein with meat odor as an ingredient for improving the sensory quality of meat analog and soy burger

Even with the growing consumption of plant-based products, the consumption of soy-based products is still a limitation due to the off-flavor of soy. Thus, two studies were performed using textured soy protein (TSP) with meat odor as meat analog and as soy burger. TSP with meat odor was produced by adding thiamine (aroma precursor) to soy protein concentrate (SPC) before extrusion. Three TSP were used in each study: one without thiamine and two with thiamine but with different moisture contents of the SPC. TSP with thiamine did not affect technological or physical properties of the products. For meat analogs, the samples with thiamine showed greater odor acceptance and greater intensities of meat odor, burnt aftertaste, and aromatic in relation to the sample without thiamine, as well as lower intensity of soy odor. For soy burgers, the samples with thiamine had higher acceptances of odor and flavor and overall acceptance, and higher intensities of chicken odor and aromatic in comparison to the sample without thiamine, as well as lower intensity of soy/vegetable odor. The use of TSP with thiamine raises the sensory quality of meat analogue and soy burger, being an interesting alternative in obtaining soy-based products with lower soy odor.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05875-0.

Effect of heat treatment on the release of off-flavor compounds in soy protein isolate

The effects of different heat treatment conditions (65℃ for 30 min, 75℃ for 15 min, and 95℃ for 2, 15 and 30 min) on the evolution of off-flavor compounds in soy protein isolate (SPI) were investigated in terms of lipid oxidation, Maillard reaction and protein structural characteristics. Higher off-flavor concentrations were observed in control and 65℃ treated SPI due to lipoxygenase-mediated enzymatic lipid oxidation. Protein structure played an important role in the release of off-flavors above 65℃. When heated from 75℃ to 95℃ for 2 min, Maillard reaction occurred, glycinin was completely denatured, the particle size increased and the small molecular weight soluble aggregates were formed, resulting in an increase in the content of partial off-flavors. The off-flavor content decreased with time at 95℃, accompanied by the formation of larger molecular weight soluble aggregates. This finding provides practical implications for the beany removal through the SPI structural regulation.

Food off-odor generation, characterization and recent advances in novel mitigation strategies

The pronounced perception of off-odors poses a prevalent issue across various categories of food ingredients and processed products, significantly exerting negative effects on the overall quality, processability, and consumer acceptability of both food items and raw materials. Conventional methods such as brining, marinating, and baking, are the main approaches to remove the fishy odor. Although these methods have shown notable efficacy, there are simultaneously inherent drawbacks that ultimately diminish the processability of raw materials, encompassing alterations in the original flavor profiles, the potential generation of harmful substances, restricted application scopes, and the promotion of excessive protein/lipid oxidation. In response to these challenges, recent endeavors have sought to explore innovative deodorization techniques, including emerging physical processing approaches, the development of high-efficiency adsorbent material, biological fermentation methods, and ozone water rinsing. However, the specific mechanisms underpinning the efficacy of these deodorization techniques remain not fully elucidated. This chapter covers the composition of major odor-causing substances in food, the methodologies for their detection, the mechanisms governing their formation, and the ongoing development of deodorization techniques associated with the comparison of their advantages, disadvantages, and application mechanisms. The objective of this chapter is to furnish a theoretical framework for enhancing deodorization efficiency through fostering the development of suitable deodorization technologies in the future.

Effect of pH-shifting on the water holding capacity and gelation properties of mung bean protein isolate

In this study, alkaline pH-shifting modified the globular structure of mung bean protein isolate (MBPI) to form flexible and stretched structures. In contrast, acidic pH-shifting increased the rigidity of MBPI. The increased flexibility (at the level of the secondary structure) and newly exposed intermolecular amino acid groups induced by alkaline pH-shifting improved the water holding capacity and gelation properties of proteins. Specifically, MBPI treated at pH 12 (MP12) showed the most flexible structure and highest water holding capacity and gel formation properties (least gelation concentration). The water-holding capacity of native MBPI increased from 1.56 g/g to 4.81 g/g, and its least gelation concentration decreased from 22 % to 15 % by pH-shifting at pH 12. Furthermore, MP12 formed stronger and more elastic heat-induced gels than native MBPI. We identified significant differences in the structural properties and water holding capacity, and gelation properties of acidic and alkaline pH-shifted MBPI and investigated the gelation properties of MP12 including rheological and morphological analyses. Our findings can facilitate the use of mung beans as a protein source in a wide range of food applications, including plant-based and processed meats.

Protein-glutaminase improves water-/oil-holding capacity and beany off-flavor profiles of plant-based meat analogs

An unresolved challenge for plant-based meat analogs (PBMAs) is their lack of juiciness. Saturated fats significantly contribute to the juiciness of PBMAs, but there are concerns about the undesirable health effects related to saturated fats; thus, demand for their replacement with vegetable unsaturated oils has increased. Although many food additives are used to reduce the leakage of unsaturated oils, this solution cannot meet the clean-label requirements that have been trending in recent years. In this study, we aimed to develop better consumer-acceptable methods using protein-glutaminase (PG) to improve the juiciness of PBMA patties to meet clean-label trends. We found no significant difference between the visual surface of control and PG-treated textured vegetable proteins (TVPs). However, the microstructure of PG-treated TVP had a more rounded shape than that of the control TVP as observed under a scanning electron microscope. After grilling process, the PBMA patties composed of PG-treated TVP showed significantly higher liquid-holding capacities (a juiciness indicator) than the control patties. This suggested that PG treatment could potentially produce PBMA patties with increased juiciness. Interestingly, after the PG-treated TVP underwent the wash process, we found that PG treatment of TVP easily reduced the various beany off-flavor compounds by 58-85%. Moreover, the results of the in vitro protein digestion test showed that the amounts of free amino nitrogen released from PBMA patties composed of PG-treated TVP were 1.5- and 1.7-fold higher than those from control patties in the gastric and intestinal phases, respectively. These findings indicate that PG treatment of TVP could enhance the physical, sensory, and nutritional properties of PBMA patties and meet the clean-label requirements.

Soybean genetics, genomics, and breeding for improving nutritional value and reducing antinutritional traits in food and feed

Soybean [Glycine max (L.) Merr.] is a globally important crop due to its valuable seed composition, versatile feed, food, and industrial end-uses, and consistent genetic gain. Successful genetic gain in soybean has led to widespread adaptation and increased value for producers, processors, and consumers. Specific focus on the nutritional quality of soybean seed composition for food and feed has further elucidated genetic knowledge and bolstered breeding progress. Seed components are historical and current targets for soybean breeders seeking to improve nutritional quality of soybean. This article reviews genetic and genomic foundations for improvement of nutritionally important traits, such as protein and amino acids, oil and fatty acids, carbohydrates, and specific food-grade considerations; discusses the application of advanced breeding technology such as CRISPR/Cas9 in creating seed composition variations; and provides future directions and breeding recommendations regarding soybean seed composition traits.

Pulsed electric field treatment of soymilk: Impact on Kunitz trypsin inhibitor allergenicity, antinutritional factor, and aroma characteristics

Allergens, antinutritional factors, and lipoxygenase (LOX) enzyme present in soymilk limit its consumption as vegan milk. Therefore, the present study focuses on reducing these limiting factors using pulsed electric field (PEF) treatment. In this regard, 20-40 kV/cm electric field was applied to soymilk for the effective treatment periods of 450, 1350, and 2250 ms. After the treatment, a reduction in pH (6.60 ± 0.10 to 6.47 ± 0.12) and an increase in the conductivity (173.03 ± 0.40 to 177.33 ± 0.72 µS) were observed. Furthermore, FTIR (Fourier Transform Infrared Spectroscopy), UV (Ultra Violet) intrinsic spectra, and CD (Circular Dichroism) spectra (α-helix reduction and β-sheet increase) data indicated mild structural changes in the proteins of soymilk. As a result, PEF treatment reduced the soymilk allergenicity (67.33 ± 20.48%), LOX activity (69.45 ± 9.38%), and trypsin inhibitor activity (75.61 ± 4.04%). Apart from that, the color, viscosity, and volatiles of soymilk also had significant changes due to PEF treatment. The aroma changes in PEF-treated soymilk were highly influenced by two major principal component (PC1 & PC2) groups and they accounted for about 70% of the aroma variations. However, these changes were mild and did not induce any off-flavors and the treatment remained effective against the quality hazards like allergens, antinutritional factors, and LOX enzyme. PRACTICAL APPLICATION: PEF treatment of soymilk reduces the possible allergic reactions in human body at least by 30%. Further, it reduces the antinutritional factor and off-odor inducing compounds. Therefore, the PEF treatment can be used in industries as a pre-treatment to produce allergen and antinutritional compounds free protein isolates from soybeans.

Effects of ultrasonic treatment on the structural, functional properties and beany flavor of soy protein isolate: Comparison with traditional thermal treatment

This research explored the influences of ultrasonic and thermal treatments on the structure, functional properties, and beany flavor of soy protein isolate (SPI). In comparison with traditional thermal treatment, ultrasonic treatment effectively induced protein structural unfolding and exposure of hydrophobic groups, which reduced relative content of α-helix, increased relative content of β-turn, β-sheet and random coil, and improved the solubility, emulsifying and foaming properties of SPI. Both treatments significantly decreased the species and contents of flavor compounds, such as hexanal, (E)-2-nonenal, (Z)-2-heptenal and (E)-2-hexenal in SPI. The relative content of hexanal in the major beany flavor compound decreased from 11.69% to 6.13% and 5.99% at 350 W ultrasonic power and 150 s thermal treatment procedure, respectively. After ultrasonic treatment, structural changes in SPI were significantly correlated with functional properties but showed a weak correlation with flavor. Conversely, the opposite trend was observed for thermal treatment. Thus, using ultrasonic treatment to induce and stabilise the denatured state of proteins is feasible to improve the functional properties and beany flavor of SPI.

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.

A Review of Plant-Based Drinks Addressing Nutrients, Flavor, and Processing Technologies

Plant-based drinks have garnered significant attention as viable substitutes for traditional dairy milk, providing options for individuals who are lactose intolerant or allergic to dairy proteins, and those who adhere to vegan or vegetarian diets. In recent years, demand for plant-based drinks has expanded rapidly. Each variety has unique characteristics in terms of flavor, texture, and nutritional composition, offering consumers a diverse range of choices tailored to meet individual preferences and dietary needs. In this review, we aimed to provide a comprehensive overview of the various types of plant-based drinks and explore potential considerations including their nutritional compositions, health benefits, and processing technologies, as well as the challenges facing the plant-based drink processing industry. We delve into scientific evidence supporting the consumption of plant-based drinks, discuss their potential roles in meeting dietary requirements, and address current limitations and concerns regarding their use. We hope to illuminate the growing significance of plant-based drinks as sustainable and nutritious alternatives to dairy milk, and assist individuals in making informed choices regarding their dietary habits, expanding potential applications for plant-based drinks, and providing necessary theoretical and technical support for the development of a plant-based drink processing industry.

Research Advances in Plant Protein-Based Products: Protein Sources, Processing Technology, and Food Applications

Plant proteins are high-quality dietary components of food products. With the growing interest in sustainable and healthy food alternatives, plant proteins have gained significant attention as viable substitutes for animal-based proteins. Understanding the diversity of protein sources derived from plants, novel processing technology, and multiple applications is crucial for developing nutritious and sustainable plant protein-based products. This Review summarizes the natural sources of traditional and emerging plant proteins. The classifications, processing technologies, and applications of plant protein-based products in the food industry are explicitly elucidated. Moreover, the advantages and disadvantages of plant protein-based food products are revealed. Strategies such as protein fortification and complementation to overcome these shortcomings are critically discussed. We also demonstrate several issues that need to be addressed in future development.

Composition, functional properties, health benefits and applications of oilseed proteins: A systematic review

Common oilseeds, such as soybean, peanut, rapeseed, sunflower seed, sesame seed and chia seed, are key sources of edible vegetable oils. Their defatted meals are excellent natural sources of plant proteins that can meet consumers' demand for health and sustainable substitutes for animal proteins. Oilseed proteins and their derived peptides are also associated with many health benefits, including weight loss and reduced risks of diabetes, hypertension, metabolic syndrome and cardiovascular events. This review summarizes the current status of knowledge on the protein and amino acid composition of common oilseeds as well as the functional properties, nutrition, health benefits and food applications of oilseed protein. Currently, oilseeds are widely applied in the food industry regarding for their health benefits and good functional properties. However, most oilseed proteins are incomplete proteins and their functional properties are not promising compared to animal proteins. They are also limited in the food industry due to their off-flavor, allergenic and antinutritional factors. These properties can be improved by protein modification. Therefore, in order to make better use of oilseed proteins, methods for improving their nutrition value, bioactive activity, functional and sensory characteristics, as well as the strategies for reducing their allergenicity were also discussed in this paper. Finally, examples for the application of oilseed proteins in the food industry are presented. Limitations and future perspectives for developing oilseed proteins as food ingredients are also pointed out. This review aims to foster thinking and generate novel ideas for future research. It will also provide novel ideas and broad prospects for the application of oilseeds in the food industry.

Potential of combining natural-derived antioxidants for improving broiler meat shelf-life - A review

Synthetic antioxidants have shown adverse effects on consumers. The review, thus, aims to assess the effect of marinating broiler meat with plant leaves-derived antioxidants potential for improving shelf-life and human health. Broiler meat loss and waste due to spoilage is more than three million kg annually, thus, extending shelf-life by reducing initial microbial load and autoxidation is essential. Adding various antioxidants would reduce oxidation of protein and fatty acids improving nutritional shelf-life through synergic interactions. Antioxidant synergetic effects also improves reduction in microbiota proliferation leading to the delayed development of off flavours and deterioration of meat colour. To reduce initial microbial load and autoxidation effects, the inclusion of polyphenols and antioxidants from varying sources by mixing various antioxidants would lead to improved synergic effects.

Flavour by design: food-grade lactic acid bacteria improve the volatile aroma spectrum of oat milk, sunflower seed milk, pea milk, and faba milk towards improved flavour and sensory perception

BACKGROUND

The global market of plant-based milk alternatives is continually growing. Flavour and taste have a key impact on consumers' selection of plant-based beverages. Unfortunately, natural plant milks have only limited acceptance. Their typically bean-like and grassy notes are perceived as "off-flavours" by consumers, while preferred fruity, buttery, and cheesy notes are missing. In this regard, fermentation of plant milk by lactic acid bacteria (LAB) appears to be an appealing option to improve aroma and taste.

RESULTS

In this work, we systematically studied LAB fermentation of plant milk. For this purpose, we evaluated 15 food-approved LAB strains to ferment 4 different plant milks: oat milk (representing cereal-based milk), sunflower seed milk (representing seed-based milk), and pea and faba milk (representing legume-based milk). Using GC‒MS analysis, flavour changes during anaerobic fermentations were studied in detail. These revealed species-related and plant milk-related differences and highlighted several well-performing strains delivered a range of beneficial flavour changes. A developed data model estimated the impact of individual flavour compounds using sensory scores and predicted the overall flavour note of fermented and nonfermented samples. Selected sensory perception tests validated the model and allowed us to bridge compositional changes in the flavour profile with consumer response.

CONCLUSION

Specific strain-milk combinations provided quite different flavour notes. This opens further developments towards plant-based products with improved flavour, including cheesy and buttery notes, as well as other innovative products in the future. S. thermophilus emerged as a well-performing strain that delivered preferred buttery notes in all tested plant milks. The GC‒MS-based data model was found to be helpful in predicting sensory perception, and its further refinement and application promise enhanced potential to upgrade fermentation approaches to flavour-by-design strategies.

Application of ultrasound and its real-time monitoring of the acoustic field during processing of tofu: Parameter optimization, protein modification, and potential mechanism

Tofu is nutritious, easy to make, and popular among consumers. At present, traditional tofu production has gradually become perfect, but there are still shortcomings, such as long soaking time, serious waste of water resources, and the inability to realize orders for production at any time. Moreover, tofu production standards have not yet been clearly defined, with large differences in quality between them, which is not conducive to industrialized and large-scale production. Ultrasound has become a promising green processing technology with advantages, such as high extraction rate, short processing time, and ease of operation. This review focused on the challenges associated with traditional tofu production during soaking, grinding, and boiling soybeans. Moreover, the advantages of ultrasonic processing over traditional processing like increasing nutrient content, improving gel properties, and inhibiting the activity of microorganisms were explained. Furthermore, the quantification of acoustic fields by real-time monitoring technology was introduced to construct the theoretical correlation between ultrasonic treatments and tofu processing. It was concluded that ultrasonic treatment improved the functional properties of soybean protein, such as solubility, emulsifying properties, foamability, rheological properties, gel strength, and thermal stability. Therefore, the application of ultrasonic technology to traditional tofu processing to optimize industrial parameters is promising.

An integrated untargeted metabolomic approach reveals the quality characteristics of black soybeans from different geographical origins in China

Black soybeans are extensively planted and consumed in China due to their high nutritional value and numerous health benefits. However, very few is known about the characteristic metabolites of black soybeans from different geographical origins in China. In the present study, 31 black soybean samples were collected from 11 main producing provinces in China. A combined metabolomics approach using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) and gas chromatography coupled to an Orbitrap mass analyzer (GC-orbitrap-MS) was performed for the first time to comprehensively investigate the metabolite variability among the black soybeans from different geographical origins. A total of 48 differential non-volatile metabolites and 14 differential volatile metabolites were identified based on orthogonal partial least squares discriminant analysis (OPLS-DA) coupled with analysis of variance (ANOVA). Higher procyanidin B1, procyanidin B2, epicatechin, malonylated isoflavones, and β-pinene were observed in Gansu black soybeans. Guangxi black soybeans had higher amounts of linoleic acid and its oxidation products of hexanal and pentane. The black soybeans from Xinjiang and Yunnan were found to have higher delphinidin-derived anthocyanins, gamma-glutamyl peptides, and aromatic hydrocarbons. The characteristic metabolites of black soybeans from other geographical origins were also clarified. This study indicated that the integrated untargeted metabolomic approach can be a powerful tool to provide knowledge for developing specialty black soybeans.

Control of Beany Flavor from Soybean Protein Raw Material in Plant-Based Meat Analog Processing

The development of plant-based meat analogs is currently hindered by the beany flavor generated by raw soybean protein and extrusion processing. Wide concern has led to extensive research on the generation and control of this unwanted flavor, as an understanding of its formation in raw protein and extrusion processing and methods through which to control its retention and release are of great significance for obtaining ideal flavor and maximizing food quality. This study examines the formation of beany flavor during extrusion processing as well as the influence of interaction between soybean protein and beany flavor compounds on the retention and release of the undesirable flavor. This paper discusses ways to maximize control over the formation of beany flavor during the drying and storage of raw materials and methods to reduce beany flavor in products by adjusting extrusion parameters. The degree of interaction between soybean protein and beany compounds was found to be dependent on conditions such as heat treatment and ultrasonic treatment. Finally, future research directions are proposed and prospected. This paper thus provides a reference for the control of beany flavor during the processing, storage, and extrusion of soybean raw materials used in the fast-growing plant-based meat analog industry.

Microbiology, flavor formation, and bioactivity of fermented soybean curd (furu): A review

Soybeans are an important plant-based food but its beany flavor and anti-nutritional factors limit its consumption. Fermentation is an effective way to improve its flavor and nutrition. Furu is a popular fermented soybean curd and mainly manufactured in Asia, which has been consumed for thousands of years as an appetizer because of its attractive flavors. This review first classifies furu products on the basis of various factors; then, the microorganisms involved in its fermentation and their various functions are discussed. The mechanisms for the formation of aroma and taste compounds during fermentation are also discussed; and the microbial metabolites and their bioactivities are analyzed. Finally, future prospects and challenges are introduced and further research is proposed. This information is needed to protect the regional characteristics of furu and to regulate its consistent quality. The current information suggests that more in vivo experiments and further clinical trials are needed to confirm its safety and the microbial community needs to be optimized and standardized for each type of furu to improve the production process.

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.

Physicochemical Characteristics and Flavor Properties of Texturized Dual-Proteins Extrudates: Effect of Surimi to Soybean Flour Ratio

This study investigated the effects of surimi to soybean flour ratio (0:10, 1:9, 2:8, 3:7, 4:6) on the physicochemical characteristics and flavor properties of dual-proteins extrudates. The increasing ratio of surimi improved the color of extrudates and raised the apparent viscosity of the mixed raw materials, which led to the decrease of extrudates' thickness. The excess ratio of surimi and soybean flour (more than 2:8) was bad for extrudates' physicochemical characteristics with sharply decreased tensile strength, macroscopic longitudinal fracture, broken and unevenly distributed microstructure, increased water mobility and decreased free water content. However, the increasing ratio of surimi had no effect on the protein secondary structure of extrudates. Sensory evaluation, E-tongue and E-nose analysis suggested that adding surimi significantly changed the flavor properties of extrudates, with increased sweetness and umami taste, and an appropriate ratio (2:8 or 3:7) could reduce the beany flavor and without an obvious fishy off-flavor.

Evaluation of dual-frequency multi-angle ultrasound on physicochemical properties of tofu gel and its finished product by TOPSIS-entropy weight method

The effects of dual-frequency (40 + 20 kHz) and multi-angle ultrasound (0°, 30°, 45°) on the coagulation state, network structure, flavor and protein conformation of tofu gel were studied. The results showed that the gel flavor of 40 + 20 kHz 0° group was the best and fluorescence intensity was low. The gel flavor in the 40 + 20 kHz 30° group was better than the group without ultrasound, and hydrophobic interaction and disulfide bond content was the largest. Meanwhile, the degree of protein cross-link was increased. The gel in 40 + 20 kHz 45° group had tightly gel state, high thermal stability, but poor flavor. Combined with The Order Preference by Similarity to Ideal Solution (TOPSIS)-entropy weight method, the 40 + 20 kHz 30° group, was the best ultrasonic treatment of gel. It can change the interaction between proteins, promote protein cross-link, and form a uniform and dense gel network. Finally, the hardness and moisture content of finished tofu were increased significantly, and the quality was improved.

Consumer Perception and Acceptability of Plant-Based Alternatives to Chicken

The prevalence of plant-based alternatives (PBAs) to meat in the marketplace has been increasing in recent years due to consumer demand. One of these plant-based products has aimed to mimic chicken products, specifically chicken nuggets. However, few sensory studies have been conducted on these products. The objective of this study is to evaluate the sensory properties, acceptability, and consumer perception of these PBAs. Participants (n = 105) were asked to evaluate five PBAs and a control (chicken nugget) using hedonic scales and a check-all-that-apply question. They also answered an open-ended comment question about PBAs. The participants separated the control from the PBAs in terms of their hedonic scores and sensory properties. They separated the PBAs based on their textural properties and if they had off-flavors. Participants disliked PBAs that were associated with an aftertaste, as well as beany, fibrous, and chewy attributes. The participants believed the PBAs currently on the market did not successfully mimic a chicken nugget and that improvement is needed, but they did believe PBAs are environmentally friendly.

Cyclodextrins produced by cyclodextrin glucanotransferase mask beany off-flavors in plant-based meat analogs

The widening gap between the supply and demand for meat products has increased the need to produce plant-based meat analogs as protein sources. Meat analogs are principally composed of soy-based textured vegetable proteins. Despite ongoing technical developments, one of the unresolved challenges for plant-based meat analogs is the off-flavor from soy, which limits their consumer acceptability. Among the various methods developed for overcoming this challenge, masking the beany flavors with cyclodextrins (CDs) is an attractive, cost-effective, and safe strategy. However, the current established CD treatment method does not meet the requirement for a clean-label. This study aimed to develop more acceptable off-flavor-masking technologies for plant-based patties for modern clean-label preferences using enzymatic methods. We used the cyclodextrin glucanotransferase (CGT), “Amano,” as a commercially available food-grade CGT. The CGT-catalyzed reaction in plant-based patties yielded 17.1 g/L CD. As CGT could yield sufficient CD in the patties, we investigated whether CDs produced by CGT could mask the off-flavors released from the plant-based patties. The CGT-treated patties had significantly lower volatilization amounts of the known beany off-flavor-generating compounds compared to the non-treated patties. Moreover, CGT treatment improved the texture of the patties and increased their water- and oil-holding capacity. As CGT is rendered inactive after cooking, it would not be considered an additive. These findings indicated that CDs produced by the CGT reaction could effectively mask off-flavors of meat analogs and improve their physical properties while meeting clean-label requirements.

Surmounting the off-flavor challenge in plant-based foods

Plant-based food products have been receiving an astronomical amount of attention recently, and their demand will most likely soar in the future. However, their unpleasant, intrinsic flavor and odor are the major obstacles limiting consumer's acceptance. These off-flavors are often described as "green," "grassy," "beany," "fatty" and "bitter." This review highlights the presence and formation of common off-flavor volatiles (aldehydes, alcohols, ketones, pyrazines, furans) and nonvolatiles (phenolics, saponins, peptides, alkaloids) from a variety of plant-based foods, including legumes (e.g. lentil, soy, pea), fruits (e.g. apple, grape, watermelon) and vegetables (e.g. carrot, potato, radish). These compounds are formed through various pathways, including lipid oxidation, ethanol fermentation and Maillard reaction (and Strecker degradation). The effect of off-flavor compounds as received by the human taste receptors, along with its possible link of bioactivity (e.g. anti-inflammatory effect), are briefly discussed on a molecular level. Generation of off-flavor compounds in plants is markedly affected by the species, cultivar, geographical location, climate conditions, farming and harvest practices. The effects of genome editing (i.e. CRISPR-Cas9), various processing technologies, such as antioxidant supplementation, enzyme treatment, extrusion, fermentation, pressure application, and different storage and packaging conditions, have been increasingly studied in recent years to mitigate the formation of off-flavors in plant foods. The information presented in this review could be useful for agricultural practitioners, fruits and vegetables industry, and meat and dairy analogue manufacturers to improve the flavor properties of plant-based foods.

Aroma compounds and consumer acceptability of soybean paste fermented by lactobacilli

Consumption of soybean-based foods is affected by the flavor of the legume; due to the presence of undesirable compounds called "beany flavors". To solve this problem, the influence of solid state fermentation by lactobacilli on the production of volatile compounds in soybean paste was determined. The volatile's production was measured by gas chromatography. Forty compounds were identified in the different soybean pastes studied. The results showed that fermentation stimulates the production of desirable volatile compounds in foods such as ketones (22-75%) and decreased unpleasant compounds (10-84%).The consumers acceptance study showed that a group of participants (30% approximately) preferred the fermented samples associated with sweet and acid aroma like yogurt. In conclusion, the fermentation positively influences the generation of desirable volatile compounds and completely reduces hexanal in one sample. Therefore, fermentation with the studied strains is a valid strategy to modify the aroma profile of a soybean-based food matrix.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05210-5.

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.