Italian legumes: effect of sourdough fermentation on lunasin-like polypeptides

Food phenolics and Lactiplantibacillus plantarum

Phenolic compounds are important constituents of plant food products. These compounds play a key role in food characteristics such as flavor, astringency and color. Lactic acid bacteria are naturally found in raw vegetables, being Lactiplantibacillus plantarum the most commonly used commercial starter for the fermentation of plant foods. Hence, the metabolism of phenolic compounds of L. plantarum has been a subject of study in recent decades. Such studies confirm that L. plantarum, in addition to presenting catalytic capacity to transform aromatic alcohols and phenolic glycosides, exhibits two main differentiated metabolic routes that allow the biotransformation of dietary hydroxybenzoic and hydroxycinnamic acid-derived compounds. These metabolic pathways lead to the production of new compounds with new biological and organoleptic properties. The described metabolic pathways involve the action of specialized esterases, decarboxylases and reductases that have been identified through genetic analysis and biochemically characterized. The purpose of this review is to provide a comprehensive and up-to-date summary of the current knowledge of the metabolism of food phenolics in L. plantarum.

Toward Sourdough Microbiome Data: A Review of Science and Patents

Technological prospecting was performed on documents related to sourdough microbiota using SCOPUS, Web of Science, Google Scholar, Espacenet and Patent Inspiration databases. Scientific articles and patents were analyzed based on three different perspectives: macro (year of publication, country, and institutions), meso (categorization as different taxonomies according to the subject evaluated), and micro (in-depth analysis of the main taxonomies, gathering the documents in subcategories). The main subject addressed in patents was the starter and product preparation, while 58.8% of the scientific publications focused on sourdough starter microbiota (identification and selection of microorganisms). Most patents were granted to companies (45.9%), followed by independent inventors (26.4%) and universities (21.8%). Sourdough products are in the spotlight when the subject is the bakery market; however, a closer integration between academia and industry is needed. Such a collaboration could generate a positive impact on the sourdough market in terms of innovation, providing a bread with a better nutritional and sensory quality for all consumers. Moreover, sourdough creates a new magnitude of flavor and texture in gastronomy, providing new functional products or increasing the quality of traditional ones.

Sourdough Fermentation as a Tool to Improve the Nutritional and Health-Promoting Properties of Its Derived-Products

Cereal products are staple foods highly appreciated and consumed worldwide. Nonetheless, due to the presence of gluten proteins, and other co-existing compounds such as amylase-trypsin inhibitors and fermentable short-chain carbohydrates in those products, their preference by consumers has substantially decreased. Gluten affects the small gut of people with celiac disease, triggering a gut inflammation condition via auto-immune response, causing a cascade of health disorders. Amylase-trypsin inhibitors and fermentable short-chain carbohydrate compounds that co-exists with gluten in the cereal-based foods matrix have been associated with several gastrointestinal symptoms in non-celiac gluten sensitivity. Since the symptoms are somewhat overlapped, the relation between celiac disease and irritable bowel syndrome has recently received marked interest by researchers. Sourdough fermentation is one of the oldest ways of bread leavening, by lactic acid bacteria and yeasts population, converting cereal flour into attractive, tastier, and more digestible end-products. Lactic acid bacteria acidification in situ is a key factor to activate several cereal enzymes as well as the synthesis of microbial active metabolites, to positively influence the nutritional/functional and health-promoting benefits of the derived products. This review aims to explore and highlight the potential of sourdough fermentation in the Food Science and Technology field.

Trends in functional food development with three-dimensional (3D) food printing technology: prospects for value-added traditionally processed food products

One of the recent, innovative, and digital food revolutions gradually gaining acceptance is three-dimensional food printing (3DFP), an additive technique used to develop products, with the possibility of obtaining foods with complex geometries. Recent interest in this technology has opened the possibilities of complementing existing processes with 3DFP for better value addition. Fermentation and malting are age-long traditional food processes known to improve food value, functionality, and beneficial health constituents. Several studies have demonstrated the applicability of 3D printing to manufacture varieties of food constructs, especially cereal-based, from root and tubers, fruit and vegetables as well as milk and milk products, with potential for much more value-added products. This review discusses the extrusion-based 3D printing of foods and the major factors affecting the process development of successful edible 3D structures. Though some novel food products have emanated from 3DFP, considering the beneficial effects of traditional food processes, particularly fermentation and malting in food, concerted efforts should also be directed toward developing 3D products using substrates from these conventional techniques. Such experimental findings will significantly promote the availability of minimally processed, affordable, and convenient meals customized in complex geometric structures with enhanced functional and nutritional values.

Valle Agricola Chickpeas: Nutritional Profile and Metabolomics Traits of a Typical Landrace Legume from Southern Italy

Chickpea (Cicer arietinum L.) from Valle Agricola is a legume cultivated in Southern Italy whose intake is strictly linked to rural traditions. In order to get new biochemical insight on this landrace and to promote its consumption and marketing, nutritional values (moisture content, total proteins, lipids, total and free amino acids) and metabolic traits are deeply investigated. Valle Agricola chickpea is nutritionally rich in proteins (19.70 g/100 g) and essential amino acids (7.12 g/100 g; ~40% of total). Carbohydrates, whose identity was unraveled by means of UHPLC-HR MS/MS analysis, were almost 60% of chemicals. In particular, a di-galactosylglycerol, a pinitol digalactoside, and a galactosylciceritol were found as constitutive, together with different raffinose-series oligosaccharides. Although lipids were the less constitutive compounds, glycerophospholipids were identified, while among free fatty acids linoleic acid (C18:2) was the most abundant, followed by oleic (C18:1) and palmitic (C16:0) acids. Isoflavones and hydroxybenzoic acid derivatives were also detected. Valle Agricola chickpeas showed very good levels of several mineral nutrients, especially magnesium (164 mg/100 g), potassium (748 mg/100 g), calcium (200 mg/100 g), zinc (4.20 mg/100 g) and manganese (0.45 mg/100 g). The boiling process favorably decreases anti-trypsin and anti-chymotrypsin activities, depleting this precious seed of its intrinsic antinutritional factors.

Production of glycerol by Lactobacillus plantarum NRRL B-4496 and formation of hexamine during fermentation of pea protein enriched flour

Suspensions of pea protein enriched flour (PP) inoculated with Lactobacillus plantarum NRRL B-4496 and uninoculated PP suspensions were incubated in vials covered with airtight caps. Organic compound compositions of fermented and unfermented PP suspensions (F-PP and U-PP, respectively) were analyzed using solid phase microextraction (SPME) coupled with gas chromatography - mass-spectrometry (GCMS). Acetic acid was detected in all samples; pH dropped from pH 6.5 to pH 4.1 in L. plantarum F-PP and to pH 5.3 in uninoculated F-PP. Abundance of acetic acid and minuscule presence of lactic acid in L. plantarum F-PP suggested that fermentation proceeded preferentially via the pyruvate formate lyase (PFL) pathway. Nonetheless, glycerol appeared to be the most abundant compound in L. plantarum F-PP samples; colorimetric analysis indicated that its average concentration in these samples was 1.05 g/L. A metabolic switch from the PFL pathway to glycerol production might occur due to acidity tolerance limitations of L. plantarum, glycerol production being associated with the release of phosphate, which can act as a buffer. Fermentation of PP by L. plantarum also led to formation of hexamine, which is a known food preservation agent. Presence of naturally formed hexamine and glycerol in food products may render using chemical additives needless.

Bioprocessing of common pulses changed seed microstructures, and improved dipeptidyl peptidase-IV and α-glucosidase inhibitory activities

Type 2 diabetes mellitus (T2DM) is a leading cause of death globally. T2DM patients experience glucose intolerance, and inhibitors of dipeptidyl peptidase IV (DPP-IV) and α-glucosidase are used as drugs for T2DM management. DPP-IV and α-glucosidase inhibitors are also naturally contained in foods, but their potency can be affected by the food matrix and processing methods. In this study, germination and solid-state fermentation (SSF) were used to alter pulse seed microstructures, to convert compounds into more bioactive forms, and to improve their bioaccessibility. Germination substantially modified the seed microstructure, protein digestibility, contents and profiles of phenolic compounds in all the pulses. It also increased DPP-IV and α-glucosidase inhibitory activities in chickpeas, faba beans and yellow peas. Compared to germination, SSF with Lactobacillus plantarum changed the content and the profile of phenolic compounds mainly in yellow peas and green lentils because of greater disruption of the seed cell wall. In the same pulses, heat treatment and SSF of flour increased DPP-IV and α-glucosidase inhibitory activities. The results of this study suggest that germination and SSF with L. plantarum are effective and simple methods for modulating phenolic and protein profiles of common pulses and improve the action on DPP-IV and α-glucosidase.

Using Pulses in Baked Products: Lights, Shadows, and Potential Solutions

Nowadays, consumers are more conscious of the environmental and nutritional benefits of foods. Pulses-thanks to both nutritional and health-promoting features, together with their low environmental impact-satisfy the demand for high-protein/high-fiber products. However, their consumption is still somewhat limited in Western countries, due to the presence of antinutrient compounds including phytic acid, trypsin inhibitors, and some undigested oligosaccharides, which are responsible for digestive discomfort. Another limitation of eating pulses regularly is their relatively long preparation time. One way to increase the consumption of pulses is to use them as an ingredient in food formulations, such as bread and other baked products. However, some sensory and technological issues limit the use of pulses on an industrial scale; consequently, they require special attention when combined with cereal-based products. Developing formulations and/or processes to improve pulse quality is necessary to enhance their incorporation into baked products. In this context, this study provides an overview of strengths and weaknesses of pulse-enriched baked products focusing on the various strategies-such as the choice of suitable ingredients or (bio)-technological approaches-that counteract the negative effects of including pulses in baked goods.

Industrial production of sourdoughs for the baking branch - An overview

Sourdoughs are produced both in artisanal and industrial size. Sourdough manufacturers deliver the baking branch either with starters for production of in-house sourdoughs or with fully fermented sourdough products. In the latter case sourdough production is separated in time and space from the bread production. A big part of this convenience products are dried sourdoughs, which are mainly produced from rye and wheat flour, but also from other starch containing plants, like pseudocereals or legumes. The requirements regarding the raw materials used differ from that used for baking bread. The most applied drying techniques for sourdoughs are drum and spray-drying. Compared with other foods, sourdough and sourdough products have only a low risk regarding food safety due to pH < 4.2, however formation of biogenic amines or acrylamide has taken into account. More tools for sourdough authentication are needed but, before developing and validating methods, it would be necessary to include different sourdough products in a clear regulatory framework.

Effect of selected strains of lactobacilli on the antioxidant and anti-inflammatory properties of sourdough

Sourdough fermentation of cereal foods is an excellent source of obtaining peptides due to the ability of lactic acid bacteria to activate cereal proteases and produce strain-specific peptidases. With the aim of identifying the lactic acid bacterial strains potentially most effective in producing bioactive peptides, 131 lactobacilli isolates from Italian sourdoughs, used in baking technology, have been screened for proteolytic and peptidase activity. Of these, 23 strains were selected and singly inoculated in liquid sourdoughs from which a Low Molecular Weight fraction containing peptides was obtained. Evaluation of the antioxidant and anti-inflammatory activities of the extracts was performed on cultured cells (RAW 264.7 murine macrophage, murine H-end endothelium cells and Human intestinal Caco-2 cells) by assaying Reactive Oxygen Species (ROS) content, NFkB/IkB expression level and Interleukin-1β production. As a result, three lactobacilli strains showed a high antioxidant and anti-inflammatory ability enabling the development of model sourdoughs that will potentially increase the nutritional benefits of bread.

Updating the research on the chemopreventive and therapeutic role of the peptide lunasin

Chronic diseases have become the medical challenge of the 21st century because of their high incidence and mortality rates. Modulation of diet and lifestyle habits is considered as the best strategy for the prevention of these disorders. Health promoting benefits beyond their nutritional effects have been described for multiple dietary compounds. Among these compounds, the peptide lunasin is considered as one of the most promising. Naturally present in soybean, lunasin has been extensively studied in the last two decades because of its potential against chronic diseases such as cancer, cardiovascular and immunological disorders. The purpose of this article is to summarise the evidence on the presence of lunasin in soybean and derived foods, and its bioavailability once it is orally ingested. The protective and therapeutic effects of this peptide against cancer, oxidative stress, inflammation, and high cholesterol levels as well as the molecular mechanisms of action involved in these effects are also described in this review. © 2017 Society of Chemical Industry.

Exopolysaccharides Production during the Fermentation of Soybean and Fava Bean Flours by Leuconostoc mesenteroides DSM 20343

Consumption of legumes is highly recommended due to their beneficial properties. Thus, there is a great interest in developing new legume-based products with good texture. In situ produced microbial exopolysaccharides (EPS) are regarded as efficient texture modifiers in the food industry. In this study, soybean and fava bean flours with different levels of added sucrose were fermented by Leuconostoc mesenteroides DSM 20343. After fermentation, a significant increase in viscosity was observed. Sugars, glucans, fructans, mannitol, lactic acid, and acetic acid were quantified to follow the EPS and metabolite production. By treating the fermented doughs selectively with dextranase or levanase, the major role of glucans in viscosity improvement was confirmed. The roles of microbial fructansucrase and endogenous α-galactosidase in degradation of raffinose family oligosaccharides (RFO) were also investigated. This study shows the potential of Ln. mesenteroides DSM 20343 in tailoring viscosity and RFO profiles in soybean and fava bean flours.

Sourdough-type propagation of faba bean flour: Dynamics of microbial consortia and biochemical implications

The microbial ecology of faba bean sourdoughs obtained from an Italian (Ita) and a Finnish (Fi) cultivar, belonging respectively to Vicia faba major and V. faba minor groups, was described by 16S rRNA gene pyrosequencing and culture-dependent analysis. The sourdoughs were propagated with traditional backslopping procedure throughout 14days. Higher microbial diversity was found in the sourdough deriving from V. faba minor (Fi), still containing residual hulls after the milling procedure. After 2days of propagation, the microbial profile of Ita sourdough was characterized by the dominance of the genera Pediococcus, Leuconostoc and Weissella, while the genera Lactococcus, Lactobacillus and Escherichia, as well as Enterobacteriaceae were present in Fi sourdoughs. Yeasts were in very low cell density until the second backslopping and were not anymore found after this time by plate count or pyrosequencing analysis. Among the lactic acid bacteria isolates, Pediococcus pentosaceus, Leuconostoc mesenteroides and Weissella koreensis had the highest frequency of occurrence in both the sourdoughs. Lactobacillus sakei was the only lactobacillus isolated from the first to the last propagation day in Fi sourdough. According to microbiological and acidification properties, the maturity of the sourdoughs was reached after 5days. The presence of hulls and the different microbial composition reflected on biochemical characteristics of Fi sourdoughs, including acidification and phenolic compounds. Moreover, proteolysis in Fi sourdough was more intense compared to Ita. The microbial dynamic of the faba bean sourdoughs showed some differences with the most studied cereal sourdoughs.

Microbial Ecology and Process Technology of Sourdough Fermentation

From a microbiological perspective, sourdough is to be considered as a specific and stressful ecosystem, harboring yeasts and lactic acid bacteria (LAB), that is used for the production of baked goods. With respect to the metabolic impact of the sourdough microbiota, acidification (LAB), flavor formation (LAB and yeasts), and leavening (yeasts and heterofermentative LAB species) are most noticeable. Three distinct types of sourdough fermentation processes can be discerned based on the inocula applied, namely backslopped ones (type 1), those initiated with starter cultures (type 2), and those initiated with a starter culture followed by backslopping (type 3). A sourdough-characteristic LAB species is Lactobacillus sanfranciscensis. A sourdough-characteristic yeast species is Candida humilis. Although it has been suggested that the microbiota of a specific sourdough may be influenced by its geographical origin, region specificity often seems to be an artefact resulting from interpretation of the research data, as those are dependent on sampling, isolation, and identification procedures. It is however clear that sourdough-adapted microorganisms are able to withstand stress conditions encountered during their growth. Based on the technological setup, type 0 (predoughs), type I (artisan bakery firm sourdoughs), type II (industrial liquid sourdoughs), and type III sourdoughs (industrial dried sourdoughs) can be distinguished. The production of all sourdoughs, independent of their classification, depends on several intrinsic and extrinsic factors. Both the flour (type, quality status, etc.) and the process parameters (fermentation temperature, pH and pH evolution, dough yield, water activity, oxygen tension, backslopping procedure and fermentation duration, etc.) determine the dynamics and outcome of (backslopped) sourdough fermentation processes.

Improving the antioxidant properties of quinoa flour through fermentation with selected autochthonous lactic acid bacteria

Lactic acid bacteria strains, previously isolated from the same matrix, were used to ferment quinoa flour aiming at exploiting the antioxidant potential. As in vitro determined on DPPH and ABTS radicals, the scavenging activity of water/salt-soluble extracts (WSE) from fermented doughs was significantly (P<0.05) higher than that of non-inoculated doughs. The highest inhibition of linoleic acid autoxidation was found for the quinoa dough fermented with Lactobacillus plantarum T0A10. The corresponding WSE was subjected to Reverse Phase Fast Protein Liquid Chromatography, and 32 fractions were collected and subjected to in vitro assays. The most active fraction was resistant to further hydrolysis by digestive enzymes. Five peptides, having sizes from 5 to 9 amino acid residues, were identified by nano-Liquid Chromatography-Electrospray Ionisation-Mass Spectra/Mass Spectra. The sequences shared compositional features which are typical of antioxidant peptides. As shown by determining cell viability and radical scavenging activity (MTT and DCFH-DA assays, respectively), the purified fraction showed antioxidant activity on human keratinocytes NCTC 2544 artificially subjected to oxidative stress. This study demonstrated the capacity of autochthonous lactic acid bacteria to release peptides with antioxidant activity through proteolysis of native quinoa proteins. Fermentation of the quinoa flour with a selected starter might be considered suitable for novel applications as functional food ingredient, dietary supplement or pharmaceutical preparations.

Sourdough-Based Biotechnologies for the Production of Gluten-Free Foods

Sourdough fermentation, a traditional biotechnology for making leavened baked goods, was almost completely replaced by the use of baker's yeast and chemical leavening agents in the last century. Recently, it has been rediscovered by the scientific community, consumers, and producers, thanks to several effects on organoleptic, technological, nutritional, and functional features of cereal-based products. Acidification, proteolysis, and activation of endogenous enzymes cause several changes during sourdough fermentation, carried out by lactic acid bacteria and yeasts, which positively affect the overall quality of the baked goods. In particular, the hydrolysis of native proteins of the cereal flours may improve the functional features of baked goods. The wheat flour processed with fungal proteases and selected lactic acid bacteria was demonstrated to be safe for coeliac patients. This review article focuses on the biotechnologies that use selected sourdough lactic acid bacteria to potentially counteract the adverse reactions to gluten, and the risk of gluten contamination.

Immunological Investigation for the Presence of Lunasin, a Chemopreventive Soybean Peptide, in the Seeds of Diverse Plants

Lunasin, a 44 amino acid soybean bioactive peptide, exhibits anticancer and anti-inflammatory properties. All soybean varieties that have been examined contain lunasin. It has also been reported in a few other plant species including amaranth, black nightshade, wheat, barley, rye, and triticale. Interestingly, detailed searches of transcriptome and DNA sequence databases of cereals failed to identify lunasin-coding sequences, raising questions about the authenticity of lunasin in cereals. To clarify the presence or absence of lunasin in cereals and other plant species, an immunological investigation was conducted utilizing polyclonal antibodies raised against the first 20 amino acid N-terminal peptide (SKWQHQQDSCRKQLQGVNLT) and a 15 amino acid C-terminal peptide (CEKHIMEKIQGRGDD) of lunasin. Protein blot analyses revealed the presence of proteins from several plants that reacted against the lunasin N-terminal peptide antibodies. However, the same proteins failed to react against the lunasin C-terminal peptide antibodies. These results demonstrate that peptides identical to soybean lunasin are absent in seeds of diverse plants examined in this study.