Effect of Lactic Acid Fermentation on Legume Protein Properties, a Review

Effect of transglutaminase crosslinking combined with lactic fermentation on the potential allergenicity and conformational structure of soy protein

BACKGROUND

Food allergies are a growing concern worldwide, with soy proteins being important allergens that are widely used in various food products. This study investigated the potential of transglutaminase (TGase) and lactic acid bacteria (LAB) treatments to modify the allergenicity and structural properties of soy protein isolate (SPI), aiming to develop safer soy-based food products.

RESULTS

Treatment with TGase, LAB or their combination significantly reduced the antibody reactivity of β-conglycinin and the immunoglobulin E (IgE) binding capacity of soy protein, indicating a decrease in allergenicity. TGase treatment led to the formation of high-molecular-weight aggregates, suggesting protein crosslinking, while LAB treatment resulted in partial protein hydrolysis. These structural changes were confirmed by Fourier transform infrared spectroscopy, which showed a decrease in β-sheet content and an increase in random coil and β-turn contents. In addition, changes in intrinsic fluorescence and ultraviolet spectroscopy were also observed. The alterations in protein interaction and the reduction in free sulfhydryl groups highlighted the extensive structural modifications induced by these treatments.

CONCLUSION

The synergistic application of TGase and LAB treatments effectively reduced the allergenicity of SPI through significant structural modifications. This approach not only diminished antibody reactivity of β-conglycinin and IgE binding capacity of soy protein but also altered the protein's primary, secondary and tertiary structures, suggesting a comprehensive alteration of SPI's allergenic potential. These findings provide a promising strategy for mitigating food allergy concerns and lay the foundation for future research on food-processing techniques aimed at allergen reduction. © 2024 Society of Chemical Industry.

Submerged fermentation of lentil protein isolate and its impact on protein functionality, nutrition, and volatile profiles

Fermentation of pulses as a clean processing technique has been reported to have a favorable impact on the functional and nutritional quality of the starting materials. Compared to commonly fermented pulses such as peas and chickpeas, limited information is available on the effect of fermentation on lentils, especially when using a high protein isolate (>80% protein) as compared to seeds or flours. Therefore, in the present work, lentil protein isolate was used as a feedstock for submerged fermentation with Aspergillus niger, Aspergillus oryzae, or Lactobacillus plantarum. After 48 h, the samples showed increased protein content with enhanced solubility and oil-holding capacity. Controlled fermentation, as opposed to spontaneous fermentation, maintained the high foaming capacity; however, all fermented samples had lower foam and emulsion stabilizing properties and reduced water-holding capacity compared to the control. The fermented proteins were also less digestible, possibly due to an increase in phenolics and saponins. New volatile compounds were identified in fermented samples that show promise for improved sensory attributes. Significant differences were observed in specific quality attributes depending on the microbial strain used. Further research is required to better understand the fermentative metabolism of microbial communities when provided high-protein lentil ingredients as growth substrates. PRACTICAL APPLICATION: Fermented lentil protein isolate has promising flavor profiles that may improve its sensory properties for food application.

Harnessing the Health and Techno-Functional Potential of Lactic Acid Bacteria: A Comprehensive Review

This review examines the techno-functional properties of lactic acid bacteria (LABs) in the food industry, focusing on their potential health benefits. We discuss current findings related to the techno-functionality of LAB, which includes acidification, proteolytic and lipolytic features, and a variety of other biochemical activities. These activities include the production of antimicrobial compounds and the synthesis of exopolysaccharides that improve food safety and consumer sensory experience. LABs are also known for their antioxidant abilities, which help reduce oxidative reactions in foods and improve their functional properties. In addition, LABs' role as probiotics is known for their promising effects on gut health, immune system modulation, cholesterol control, and general wellbeing. Despite these advantages, several challenges hinder the effective production and use of probiotic LABs, such as maintaining strain viability during storage and transport as well as ensuring their efficacy in the gastrointestinal tract. Our review identifies these critical barriers and suggests avenues for future research.

Gut health benefits and associated systemic effects provided by functional components from the fermentation of natural matrices

Recently, the role of the gut microbiota in metabolic health, immunity, behavioral balance, longevity, and intestine comfort has been the object of several studies from scientific communities. They were encouraged by a growing interest from food industries and consumers toward novel fermented ingredients and formulations with powerful biological effects, such as pre, pro, and postbiotic products. Depending on the selected strains, the operating conditions, the addition of suitable reagents or enzymes, the equipment, and the reactor configurations, functional compounds with high bioactivity, such as short-chain fatty acids, gamma-aminobutyric acid, bioactive peptides, and serotonin, can be enhanced and/or produced through fermentation of several vegetable matrices. Otherwise, their formation can also be promoted directly in the gut after the dietary intake of fermented foods: In this case, fermentation will aim to increase the content of precursor substances, such as indigestible fibers, polyphenols, some amino acids, and resistant starch, which can be potentially metabolized by endogenous gut microorganisms and converted in healthy molecules. This review provides an overview of the main functional components currently investigated in literature and the associated gut health benefits. The current state of the art about fermentation technology as a promising functionalization tool to promote the direct or indirect formation of gut-health-enhancing components was deepened, highlighting the importance of optimizing microorganism selection, system setups, and process conditions according to the target compound of interest. The collected data suggested the possibility of gaining novel functional food ingredients or products rich in functional molecules through fermentation without performing additional extraction and purification stages, which are needed when conventional culture broths are used.

Changes in Chemical Composition of Lentils, Including Gamma-Aminobutyric Acid and Volatile Compound Formation during Submerged and Solid-State Fermentation with Pediococcus acidilactici

The aim of this study was to evaluate and compare the characteristics of non-treated and fermented [via submerged (SMF) and solid-state (SSF) fermentation using Pediococcus acidilactici] lentils (Lens culinaris) grown either in pure stands (L) or relay intercropped with winter rye (LR). It was observed that the lentils were suitable substrate for lacto-fermentation. Most of the free amino acid concentrations increased in lentils after both fermentations. The highest concentration of γ-aminobutyric acid was found in SSF LR samples. However, fermentation led to higher biogenic amines (BA) content in lentils. The most abundant fatty acid in lentils was C18:2. SSF lentils showed more complex volatile compound (VC) profiles (with between nine and seventeen new VCs formed), whereas, in SMF samples, between two and five newly VCs were formed. When comparing lentil grown types, L contained significantly higher concentrations of Na, K, Ca, P, Mn, and Se, while LR contained significantly higher concentrations of Fe and Ni. To sum up, fermentation with lactic acid bacteria (LAB) contributed to the improved biological value of lentils; still, the quantity of BA needs to be considered. Further investigations into the P. acidilactici metabolism of certain compounds (such as phenolic and antinutritional compounds) in lentils during fermentation ought to be carried out.

Rapid Acidification and Off-Flavor Reduction of Pea Protein by Fermentation with Lactic Acid Bacteria and Yeasts

Pea protein is widely used as an alternative protein source in plant-based products. In the current study, we fermented pea protein to reduce off-flavor compounds, such as hexanal, and to produce a suitable fermentate for further processing. Laboratory fermentations using 5% (w/v) pea protein suspension were carried out using four selected lactic acid bacteria (LAB) strains, investigating their growth and acidification capabilities in pea protein. Rapid acidification of pea protein was achieved with Lactococcus lactis subsp. lactis strain LTH 7123. Next, this strain was co-inoculated together with either the yeasts Kluyveromyces lactis LTH 7165, Yarrowia lipolytica LTH 6056, or Kluyveromyces marxianus LTH 6039. Fermentation products of the mixed starter cultures and of the single strains were further analyzed by gas chromatography coupled with mass spectrometry to quantify selected volatile flavor compounds. Fermentation with L. lactis LTH 7123 led to an increase in compounds associated with the "beany" off-flavors of peas, including hexanal. However, significant reduction in those compounds was achieved after fermentation with Y. lipolytica LTH 6056 with or without L. lactis LTH 7123. Thus, fermentation using co-cultures of LAB and yeasts strains could prove to be a valuable method for enhancing quality attributes of pea protein-based products.

Nutritional and potential health benefits of fermented food proteins

BACKGROUND

Protein fermentation continues to gain popularity as a result of several factors, including the cost-effectiveness of the process and the positive correlation of fermented protein consumption, with a reduced risk of developing diet-related diseases such as diabetes and cardiovascular disorders, as well as their enhanced nutritional and techno-functional properties. Nonetheless, the nutritional and health benefits of food protein fermentation such as enhanced nutrient bioavailability, reduced antinutritional factors (ANFs) and enriched bioactive peptides (BAPs) are often overlooked. The present study reviewed recent work on the influence of protein fermentation on nutrition and health. In total, 322 eligible studies were identified on the Scopus and Google Scholar databases out of which 69 studies were evaluated based on our inclusion criteria.

RESULTS

Fermented protein ingredients and products show reduced ANF content, enhanced digestibility and bioavailability, and increased antioxidant and other biological activities, such as probiotic, prebiotic, angiotensin-converting enzyme inhibitory and antihypertensive properties. In addition, co-products in protein fermentation such as BAPs possess and could contribute additional sensory and flavor properties, degrade toxins, and reduce allergens in foods.

CONCLUSION

Thus, fermentation is not only a method for food preservation, but also serves as a means for producing functional food products for consumer health promotion and nutrition enrichment. © 2023 Society of Chemical Industry.

Fermented foods, their microbiome and its potential in boosting human health

Fermented foods (FFs) are part of the cultural heritage of several populations, and their production dates back 8000 years. Over the last ~150 years, the microbial consortia of many of the most widespread FFs have been characterised, leading in some instances to the standardisation of their production. Nevertheless, limited knowledge exists about the microbial communities of local and traditional FFs and their possible effects on human health. Recent findings suggest they might be a valuable source of novel probiotic strains, enriched in nutrients and highly sustainable for the environment. Despite the increasing number of observational studies and randomised controlled trials, it still remains unclear whether and how regular FF consumption is linked with health outcomes and enrichment of the gut microbiome in health-associated species. This review aims to sum up the knowledge about traditional FFs and their associated microbiomes, outlining the role of fermentation with respect to boosting nutritional profiles and attempting to establish a link between FF consumption and health-beneficial outcomes.

Techno-functional attributes of oilseed proteins: influence of extraction and modification techniques

Plant-based protein isolates and concentrates are nowadays becoming popular due to their nutritional, functional as well as religious concerns. Among plant proteins, oilseeds, a vital source of valuable proteins, are continuously being explored for producing protein isolates/concentrates. This article delineates the overview of conventional as well as novel methods for the extraction of protein and their potential impact on its hydration, surface properties, and rheological characteristics. Moreover, proteins undergo several modifications using physical, chemical, and biological techniques to enhance their functionality by altering their microstructure and physical performance. The modified proteins hold a pronounced scope in novel food formulations. An overview of these protein modification approaches and their effects on the functional properties of proteins have also been presented in this review.

Fermentation technology as a driver of human brain expansion

Brain tissue is metabolically expensive. Consequently, the evolution of humans' large brains must have occurred via concomitant shifts in energy expenditure and intake. Proposed mechanisms include dietary shifts such as cooking. Importantly, though, any new food source must have been exploitable by hominids with brains a third the size of modern humans'. Here, we propose the initial metabolic trigger of hominid brain expansion was the consumption of externally fermented foods. We define "external fermentation" as occurring outside the body, as opposed to the internal fermentation in the gut. External fermentation could increase the bioavailability of macro- and micronutrients while reducing digestive energy expenditure and is supported by the relative reduction of the human colon. We discuss the explanatory power of our hypothesis and survey external fermentation practices across human cultures to demonstrate its viability across a range of environments and food sources. We close with suggestions for empirical tests.

The Differences in Protein Degradation and Sensitization Reduction of Mangoes between Juices and Pieces Fermentation

Given the allergic reaction caused by mangoes, nonthermal food technologies for allergenicity reduction are urgently desired. This study aimed to assess the impact of kombucha fermentation on the allergenicity of mangoes. The total proteins, soluble proteins, peptides, amino acid nitrogen, the SDS-PAGE profiles of the protein extracts, and immunoreactivity of the sediment and supernatant were measured in two fermentation systems (juices and pieces fermentation). Throughout the fermentation, the pH decreased from about 4.6 to about 3.6, and the dissolved oxygen reduced about 50% on average. However, the protein degradation and sensitization reduction of mangoes were different between the two fermentation systems. In juices fermentation, there was a drop in proteins and peptides but an increase in amino acids, due to the conversion of proteins and peptides into amino acids both in the supernatant and sediment. The allergenicity decreased both in the solid and liquid phases of juices fermentation. In pieces fermentation, proteins and peptides were decreased in the solid phase but increased in the liquid phase. This was due to the fact that proteins and peptides were partly transported into the culture liquid, resulting in a decrease of allergenicity in fruit pieces and an increase in culture liquid. The principal component analysis results showed that the fermentation type had significant effects on the protein degradation and sensitization reduction, while mango variety had no significant effect. These results demonstrate that kombucha fermentation can reduce the allergenicity of mangoes, and it is more effective in juices fermentation than in pieces fermentation. The present study provides a theoretical basis for developing hypoallergenic mango products.

Fermentation of Peanut Slurry with Lactococcus lactis Species, Leuconostoc and Propionibacterium freudenreichii subsp. globosum Enhanced Protein Digestibility

Peanuts contain nutritionally relevant levels of protein, yet are poorly digestible. Fermentation is a promising technique to boost legume protein quality, but its effect on the protein quality of raw peanuts has not been investigated. This study aimed to assess the impact of fermentation on the in vitro protein digestibility and free amino acid profile of cooked peanut slurry (peanut to water ratio 1:1). Cultures used were Propionibacterium freudenreichii subsp. globosum and a commercial fresh cheese culture that contained Lactococcus lactis subsp. cremoris, lactis, lactis biovar diacetylactis, and Leuconostoc, fermenting at 38 °C for 48 h. Samples fermented with the combination of cultures showed higher protein digestibility, as well as softer texture. Significant increases were observed only in the sample fermented with the fresh cheese culture. While the fresh cheese culture improved the free amino acid profile after fermentation, the combination of the cultures decreased all free amino acid concentrations except for glutamine, alanine, and proline. The observed increases in in vitro protein digestibility and the free amino acid profile may be attributed to the proteolytic activities of the cultures.

The Impacts of Acidophilic Lactic Acid Bacteria on Food and Human Health: A Review of the Current Knowledge

The need to improve the safety/quality of food and the health of the hosts has resulted in increasing worldwide interest in acidophilic lactic acid bacteria (LAB) for the food, livestock as well as health industries. In addition to the use of acidophilic LAB with probiotic potential for food fermentation and preservation, their application in the natural disposal of acidic wastes polluting the environment is also being investigated. Considering this new benefit that has been assigned to probiotic microorganisms in recent years, the acceleration in efforts to identify new, efficient, promising probiotic acidophilic LAB is not surprising. One of these effots is to determine both the beneficial and harmful compounds synthesized by acidophilic LAB. Moreover, microorganisms are of concern due to their possible hemolytic, DNase, gelatinase and mucinolytic activities, and the presence of virulence/antibiotic genes. Hence, it is argued that acidophilic LAB should be evaluated for these parameters before their use in the health/food/livestock industry. However, this issue has not yet been fully discussed in the literature. Thus, this review pays attention to the less-known aspects of acidophilic LAB and the compounds they release, clarifying critical unanswered questions, and discussing their health benefits and safety.

NMR-Based Metabolomic Study on Phaseolus vulgaris Flour Fermented by Lactic Acid Bacteria and Yeasts

In recent years, fermented foods have attracted increasing attention due to their important role in the human diet, since they supply beneficial health effects, providing important sources of nutrients. In this respect, a comprehensive characterization of the metabolite content in fermented foods is required to achieve a complete vision of physiological, microbiological, and functional traits. In the present preliminary study, the NMR-based metabolomic approach combined with chemometrics has been applied, for the first time, to investigate the metabolite content of Phaseolus vulgaris flour fermented by different lactic acid bacteria (LAB) and yeasts. A differentiation of microorganisms (LAB and yeasts), LAB metabolism (homo- and heterofermentative hexose fermentation), LAB genus (Lactobacillus, Leuconostoc, and Pediococcus), and novel genera (Lacticaseibacillus, Lactiplantibacillus, and Lentilactobacillus) was achieved. Moreover, our findings showed an increase of free amino acids and bioactive molecules, such as GABA, and a degradation of anti-nutritional compounds, such as raffinose and stachyose, confirming the beneficial effects of fermentation processes and the potential use of fermented flours in the production of healthy baking foods. Finally, among all microorganisms considered, the Lactiplantibacillus plantarum species was found to be the most effective in fermenting bean flour, as a larger amount of free amino acids were assessed in their analysis, denoting more intensive proteolytic activity.

Valorisation through Lactic Fermentation of Industrial Wastewaters from a Bean Blanching Treatment

In recent years, scientific research and industries have been focusing on the application of biological treatments aimed at imparting functional properties to waste products from food industries according to the principles on which the circular economy model is based, namely, the recovery, valorisation, and reuse of wastes. This work aimed at exploring the possibility of valorising waters from the blanching process of dried navy beans through lactic acid fermentation using Lacticaseibacillus paracasei CBA L74 as a starter. Two samples at different solid concentrations (0.75 °Bx and 1.25 °Bx) were fermented, and, in both cases, a bacterial load of 8 Logs and a lactic acid concentration of approximately 1.3 g/L were reached, despite the lack of nutrients. An unusual pH trend, characterised by an initial decrease and unexpected final rise, was observed during the fermentation of both samples: simultaneously, an increase in protein content was observed, suggesting that the proteolytic action of the microorganism could be responsible for the release of pH-increasing substances. In both cases, a slight increase in total polyphenols (approximately 23.3–33.72%) and flavonoids (approximately 42.3–52%) due to fermentation was observed, with a corresponding improvement in antioxidant capacity (approximately 25.32–37.72%). A significant increase in saponin concentration was determined for the most concentrated blanching water (from 2.87 ± 0.28 to 6.68 ± 0.69 mgOAE/mL), leading to an improvement in foaming properties and an enhanced capacity to produce stable emulsions. The obtained results confirmed the possibility of reducing water consumption from blanching operations, as well as finding valorisation opportunities for this side stream through a safe and inexpensive fermentation treatment.

Fermentation for Designing Innovative Plant-Based Meat and Dairy Alternatives

Fermentation was traditionally used all over the world, having the preservation of plant and animal foods as a primary role. Owing to the rise of dairy and meat alternatives, fermentation is booming as an effective technology to improve the sensory, nutritional, and functional profiles of the new generation of plant-based products. This article intends to review the market landscape of fermented plant-based products with a focus on dairy and meat alternatives. Fermentation contributes to improving the organoleptic properties and nutritional profile of dairy and meat alternatives. Precision fermentation provides more opportunities for plant-based meat and dairy manufacturers to deliver a meat/dairy-like experience. Seizing the opportunities that the progress of digitalization is offering would boost the production of high-value ingredients such as enzymes, fats, proteins, and vitamins. Innovative technologies such as 3D printing could be an effective post-processing solution following fermentation in order to mimic the structure and texture of conventional products.

Genetic and Metabolite Variability among Commercial Varieties and Advanced Lines of Vicia faba L

Vicia faba L. (faba bean) is one of the most promising pulse crops due to its nutritional value and high nitrogen fixation capacity. The aim of the present study was to compare the genetic diversity and the seed metabolite profiles of five genetic materials of faba bean. Specifically, three newly developed advanced lines (KK18, KK14 and KK10) and two commercial cultivars (POLIKARPI and TANAGRA), were evaluated for this purpose. Genetic diversity among populations was assessed by SCoT molecular markers. Through UPGMA dendrogram, genetic distances between populations were estimated. Untargeted metabolomics analysis of the seeds was performed employing GC/EI/MS. The cultivar POLYKARPI exhibited the highest polymorphism. All varieties showed a higher within-cultivars and advanced lines variability than between. POLYKARPI and KK14 had the lowest genetic distances, while KK18 and TANAGRA presented the highest ones. The advanced line KK18 displayed the best nutritional profile, the highest concentration of desirable metabolites (lactic acid and trehalose), the lowest concentration of anti-nutritional factors (oxalic acid) and the lowest concentration of saturated fatty acids (palmitic and stearic acid). According to the results of the present study, KK18 line is a very promising material for further exploration and utilization in breeding programs.

Utilization of fermented and enzymatically hydrolyzed soy press cake as ingredient for meat analogues

The aim of the present study was to improve the properties of soy press cake to be utilized as an ingredient of meat analogues. Soy press cakes were fermented with lactobacillus strains, and separately hydrolyzed by cellulase/xylanase mixture and α-amylase. Meat analogues were produced with 10% fermented or hydrolyzed soy press cakes. The effect of applied processes on protein oxidation, physical and functional properties of soy press cakes were analyzed, as well as sensory and textural properties of meat analogues. The results indicated that soy press cake was a suitable source of fibre and energy with low content of saturated fatty acids, and provided plant-based proteins and essential amino acids. The study demonstrated the potential of lactic acid fermentation, and enzymatic hydrolysis to improve water- and oil-holding capacity and reduce protein oxidation in soy press cakes. L. acidophilus 336 and cellulase/xylanase mixture were recommended for fermentation and hydrolysis of soy press cakes, respectively, regarding reduction of protein oxidation. Fermentation of soy press cakes with L. plantarum P1 improved the texture of meat analogues. Press cakes fermentation reduced bitterness, increased juiciness, and balanced the taste of meat analogues. Fermented soy press cake was recommended for the production of meat analogues.

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This research was the 1st application of fermented soy press cake in meat analogue.

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Fermentation and hydrolysis improved the functional properties of soy press cakes.

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Protein oxidation in soy press cakes was reduced after fermentation and hydrolysis.

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Fermented soy press cakes improved sensory quality of the meat analogues.

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L. plantarum P1 is recommended for the fermentation of soy press cakes.