Pasta acida benefici: riduzione presenza ATI; WGA; Fodmap,s

La pasta acida, utilizzata anche per fermentare impasti di farina per la produzione di pane e prodotti secchi da forno, ha numerosi benefici tra cui: la riduzione della presenza ATI e WGA.

La ricerca “Degradation of Wheat Germ Agglutinin during Sourdough Fermentation” Rojas Tovar, Luis E. DOI https://doi.org/10.7939/r3-1474-ec31 evidenzia:
Durante la fermentazione, il pH dell’impasto è sceso a 3,9 ± 0,2, il che ha favorito la degradazione dell’ATI da oligomeri a monomeri; I monomeri ATI sono meno dannosi se consumati. Il WGA viene anche modificato durante la fermentazione del lievito naturale a seconda delle capacità riducenti dei ceppi utilizzati [1].

È stato riportato che il pH è il principale responsabile degli effetti del lievito naturale sulla struttura e sulla bioattività dell’inibitore dell’amilasi-tripsina del grano (ATI). Inoltre, i batteri lattici della pasta madre riducono i legami disolfuro e diminuiscono il potenziale redox dell’impasto. Nello specifico, la glutatione reduttasi del Fructilactobacillus sanfranciscensis riduce il glutatione dimerico ossidato a glutatione, che reagisce ulteriormente per interrompere i legami disolfuro nelle proteine, altera la loro struttura secondaria e promuove la proteolisi delle proteine legate al disolfuro. [2]

Omissis… È stato riportato che i consorzi di lattobacilli e lieviti a lievitazione naturale degradano l’ATI in modo più efficiente rispetto alle colture pure di lattobacilli e quindi possono anche influire sulla degradazione del WGA. [3]

Riferimenti:

[1] “Non Celiac Wheat Sensitivity (NCWS), an intolerance to the ingestion of wheat products, has increased considerably during the past few years. In sensitive individuals, NCWS manifests by intestinal and extra intestinal symptoms in different ways. Two wheat protein fractions have been linked to NCWS, amylase-trypsin inhibitors (ATI) and wheat germ agglutinin (WGA). Physicians recommend that individuals with NCWS adhere to a gluten free diet. However, gluten free diets are often associated with a reduced diversity of products, a higher price and lower sensory and nutritional quality. Thus, it was the objective of this study to explore the possibility of using sourdough fermentation to reduce the bioactivity of these two proteins linked to NCWS in wheat bread. White pastry flour was used to analyze ATI and whole wheat flour for WGA experiments. The analytical techniques used to determine the fate of ATIs and WGA through the fermentation were size exclusion high performance liquid chromatography (SEC-HPLC), and enzyme-linked immunosorbent assay (ELISA). During fermentation, the pH of the dough decreased to 3.9 ± 0.2, which promoted the degradation of ATI from oligomers into monomers; ATI monomers are less harmful when consumed. WGA is also modified during sourdough fermentation depending on the reducing capabilities of the strains used. Initially, commercial whole wheat flour contained 6.6 μg ± 0.7 of WGA per gram. After 24 h fermentation, doughs fermented with Latilactobacillus sakei TMW 1.22 contained 2.7 μg ± 0.4 of WGA per gram of flour, while the doughs fermented with Fructilactobacillus sanfranciscensis DSM20451 and F. sanfranciscensis DSM20451 ΔgshR contained 4.3 μg ± 0.3 and 6.5 ± 1.8 μg, respectively. The WGA-SEC chromatograms show 3 peaks for doughs fermented with F. sanfranciscensis DSM20451 ΔgshR while the chromatograms with the isogenic strain F. sanfranciscensis DSM20451 show a more complex profile with 5 peaks, one of them from a very large molecular size molecule. The concentration of WGA is lower after fermentation with lactobacilli that have high reducing capacity. Clinical studies are required to determine the safety of consumption and the possible reduction in adverse symptoms, but this is a step towards finding new options to incorporate into the diet of NCWS individuals.”

[2] omissis……..Wheat components related to NCWS are fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs), amylase-trypsin inhibitors (ATIs), and wheat germ agglutinins (WGA) [4–7]. NCWS, which is also referred to as gluten sensitivity or gluten intolerance, involves a wide variety of symptoms, including bloating, diarrhea, nausea, and intestinal damage. Extra intestinal symptoms have also been described and may include tiredness, headaches, joint pain and anxiety [5]. Symptoms of NCWS overlap with irritable bowel syndrome (IBS) [6]. Individuals affected by NCWS are normally prescribed a diet which is free of wheat products [8]. Sourdough fermentation does not eliminate gluten proteins that trigger celiac disease but the use of sourdough processes in bread making can be an alternative to gluten free diets to reduce symptoms associated with NCWS. The sourdough process involves longer fermentation times in comparison to straight dough processes, and additionally recruits the metabolic activity of lactic acid bacteria. Sourdough fermentations partially or completely degrade FODMAPs in wheat [9,10] and provide more time and more suitable conditions for wheat aspartic proteases, which are optimally active at low pH, to degrade wheat proteins [11,12]. Wheat flour contains the serine carboxypeptidase D (CPW-II), an exopeptidase with an optimum pH from 4 to 5.5 [13]. The most important proteases in wheat are aspartic proteinases [14] that associate with gluten during mixing and are optimally active at acidic pH [15,16]. Wheat aspartic proteases hydrolyze peptide bonds adjacent to arginine, lysine, phenylalanine, leucine, tyrosine and tryptophan [15,17]. The pH was reported to be primarily responsible for sourdough effects on the structure and bioactivity of the wheat amylase-trypsin inhibitor (ATI) [18]. Moreover, sourdough lactic acid bacteria reduce disulfide bonds and decrease the redox potential of the dough. Specifically, glutathione reductase of Fructilactobacillus sanfranciscensis reduces oxidized, dimeric glutathione to glutathione, which further reacts to disrupt disulfide bonds in proteins, alters their secondary structure and promotes proteolysis of disulfide-bonded proteins [12,19,20].”

[3] This study aimed to determine the fate of WGA and to assess the contribution of thiol-exchange reactions and of proteolysis to WGA modifications during sourdough fermentation. The role of thiol-exchange reactions was assessed by comparing F. sanfrancis- censis DSM20451 with its isogenic glutathione-reductase negative mutant F. sanfranciscensis DSM20451∆gshR [19,20]; the role of proteolytic activity was assessed by protease addition to sourdoughs, and by the use of chemically acidified controls [12]. This study analysed sourdoughs that were fermented with defined strains of lactic acid bacteria. This approach allows an assessment of the contribution of specific metabolic traits—acidification, glu- tathione reductase activity—to the degradation of WGA; however, sourdoughs used in artisanal and industrial practice typically include several species of lactic acid bacteria and additionally include sourdough yeasts or baker’s yeast [37]. Consortia of lactobacilli and sourdough yeasts were reported to degrade ATI more efficiently than pure cultures of lactobacilli [18] and thus may also impact WGA degradation.

Note:
“ WGA is a lectin that is located in the germ of the wheat grain. In the pH-range of 3.5 to 7.4, it forms a dimer with a size of approximately 35 kDa that is relatively heat stable [21–23]. Each monomer is stabilized by 16 intramolecular disulfide bonds [24]. WGA binds N-acetyl glucosamine and its β-(1 → 4)–linked oligomers and has weaker affinity to N- acetyl galactosamine and N-acetyl neuraminic acid [25,26]. WGA’s effects on human health are controversial. Rodent experiments concluded that WGA in doses that substantially exceeded the concentration in wheat decreased growth [27]. In cell culture experiments with Caco2 cells, WGA increased the permeability of the epithelial layer [28] and stimulated synthesis of pro-inflammatory cytokines [29]; WGA also demonstrated toxicity to acute myeloid leukemia cells without significant toxicity to normal cells [30]. The identification of antibodies targeting WGA in human serum indicates its translocation and interaction with the immune system [31]. Owing to the lack of in vivo studies, however, conclusions on the contribution of WGA to NCWS remain speculative [28,32,33].”

Parole chiave: lievito madre; proteolisi; fermentazione; agglutinina di germe di grano; sensibilità al grano; batteri dell’acido lattico

La ricerca “Sourdough Fermentation Degrades Wheat Alpha-Amylase/Trypsin Inhibitor (ATI) and Reduces Pro-Inflammatory Activity”. Xin Huang. Foods . 2020 Jul 16;9(7):943.
doi: 10.3390/foods9070943 evidenzia:

Oltre al ruolo del glutine, gli inibitori dell’α-amilasi/tripsina (ATI) sono stati recentemente identificati come attivatori di una risposta immunitaria innata nella celiachia e nella sensibilità al grano non celiaca. Gli ATI sono coinvolti nell’autodifesa delle piante contro gli insetti e possibilmente nello sviluppo del grano. In particolare, sono ampiamente resistenti alle proteasi gastrointestinali e al calore e la loro attività infiammatoria colpisce non solo l’intestino, ma anche gli organi periferici. [1]

Riferimenti

[1] “The ingestion of gluten-containing foods can cause wheat-related disorders in up to 15% of wheat consuming populations. Besides the role of gluten, α-amylase/trypsin inhibitors (ATI) have recently been identified as inducers of an innate immune response via toll-like receptor 4 in celiac disease and non-celiac wheat sensitivity. ATI are involved in plant self-defense against insects and possibly in grain development. Notably, they are largely resistant to gastrointestinal proteases and heat, and their inflammatory activity affects not only the intestine, but also peripheral organs. The aim of this study was to understand the changes of ATI throughout the sourdough and yeast-fermented bread-making processes. ATI tetramers were isolated, fluorescein-labelled, and added to a mini-dough bread-making system. When the pH decreased below 4.0 in sourdough fermentation, the ATI tetramers were degraded due to the activation of aspartic proteases, whilst in yeast fermentation, ATI tetramers remained intact. The amylase inhibitory activity after sourdough fermentation decreased significantly, while the concentration of free thiol groups increased. The glutathione reductase activity of Fructilactobacillus sanfranciscensis did not contribute to the reduction of ATI tetramers. Compared to the unfermented wheat, sourdough fermentation was able to decrease the release of pro-inflammatory cytokines monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor alpha (TNF-α) in quantitative ATI extracts added to the human monocytic cell line THP-1. The current data suggest that sourdough fermentation can degrade ATI structure and bioactivity, and point to strategies to improve product development for wheat sensitivity patients.“

Note:
“ Intestinal symptoms of NCWS are not triggered by gluten proteins but relate to wheat fructans, which protect the plant in cold and drought conditions, as well as wheat proteins including amylase trypsin inhibitors that protect the wheat grain against herbivores and fungal attack [11,12]. A pro-inflammatory effect is best documented for α-amylase/trypsin inhibitors (ATIs) that activate the toll-like receptor 4 (TLR4) complex on myeloid cells, monocytes, macrophages, and dendritic cells, to induce a mild intestinal inflammation, disturb tight junctional integrity, and promote extra-intestinal diseases like allergies, the metabolic syndrome, and fatty liver disease [13–18]. ATI are also prominent allergens in immediate-type, immunoglobulin E (IgE)-Antibody-positive allergies, such as bakers’ asthma [1]. Moreover, atypical IgE and skin test-negative wheat allergies are a prominent cause of IBS [4,5]. Therefore, ATI are considered important contributors to CD and NCWS but also other intestinal and extra-intestinal immune disorders [2,7,19,20]. ATI are present in many plants and play a protective role by inhibition of α-amylases from insects and mites [21]. ATI are associated with storage proteins in endosperm and are involved in grain maturation [22]. In bread wheat, ATI represent up to 4% of total wheat proteins, and consist of at least 14 types of subunit proteins [23]. The nomenclature of ATI subunits is inconsistent. They include wheat ATI monomer with molecular weight (MW) 12 kDa, often referred to as 0.28 inhibitor based on its electrophoretic mobility, ATI homodimer with MW 24 kDa, referred to as 0.19 and 0.53 inhibitors, and ATI heterotetramers with MW 60 kDa, also referred to as CM proteins. CM proteins, termed for their solubility in chloroform:methanol mixtures, include subunits CM1, CM2, CM3, CM16, and CM17 [23]. Each ATI subunit ranges from about 11 to 16 kDa in MW and contains 10 cysteine residues (except ATI 0.53 with 9 cysteine residues) that form five intramolecular disulfide bonds while dimers and tetramers associate in a non-covalent manner [23]. The multimeric forms of ATI determine their biological activity and the ATI tetramer is five times more active than the monomer [14]. In addition, the compact, highly disulfide-linked secondary structure of ATI is needed for their biological activity, i.e., the activation of TLR4 [13]. Reduction of these disulfide bonds or hydrolysis of ATI by proteinase K significantly decreased their bioactivity [13]. Primary structures are also involved, since 2 peptides were identified that inhibited the interaction of CM3 with TLR4 [24]. CM3 and 0.19 are the most prevalent ATI species, and were shown to have comparable bioactivity when expressed recombinantly in eukaryotic cells [13]. ATI of gluten-containing grains (wheat, barley, and rye) have potent inflammatory activity, while structurally less related ATI of oats, maize, rice, and legumes have no or low activity [14].

Parole chiave: sensibilità al grano; bioattività; immunità innata; fermentazione; batteri dell’acido lattico

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La pasta acida, utilizzata anche per fermentare impasti di farina per la produzione di pane e prodotti secchi da forno, ha numerosi benefici tra cui:  la riduzione della presenza di Fodmap’s.

La ricerca “Use of Sourdough in Low FODMA Baking” Jussi Loponen et al. 2018 foods” evidenzia:

L’utilizzo di lievito madre, con fermentazione lenta e con specifiche proprietà metaboliche mirate al FODMAP, per la realizzazione di pani con farine integrali può aiutare a ridurre notevolmente il contenuto di FODMAP nel pane senza influire sul contenuto della fibra alimentare.[1]

“Gli oligosaccaridi, i disaccaridi, i monosaccaridi e i polioli fermentabili (FODMAP) hanno effetti benefici e negativi sulla salute. Gli oligosaccaridi che non vengono idrolizzati e assorbiti nell’intestino tenue vengono rapidamente fermentati dal microbiota intestinale nell’ileo e nel colon. Diversi FODMAP fermentati dal microbiota intestinale causano costantemente sintomi avversi quando viene superata una dose di circa 0,3 g/kg di peso corporeo, corrispondente a circa 15 g/giorno. I sintomi avversi includono diarrea osmotica, distensione intestinale e gonfiore. [2]

Il microbiota nell’ileo include proteobatteri e batteri dell’acido lattico come rappresentanti dominanti; il microbiota ileale fermenta efficacemente mono- e disaccaridi ma in genere manca di enzimi extracellulari per l’idrolisi di oligosaccaridi e polisaccaridi superiori. [2]

Gli effetti benefici per la salute o prebiotici degli oligosaccaridi si riferiscono alla conversione batterica degli oligosaccaridi in acidi grassi a catena corta. Questi acidi grassi a catena corta aumentano la raccolta di energia dai carboidrati che sfuggono all’idrolisi e all’assorbimento dell’intestino tenue, migliorano le proprietà della barriera intestinale e la resistenza alle infezioni enteriche ed esercitano effetti sistemici correlati all’infiammazione, alle funzioni cognitive e al comportamento attraverso il riconoscimento specifico con la proteina G accoppiata recettori. [2]

Riferimenti

[1] A low FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet allows most irritable bowel syndrome (IBS) patients to manage their gastrointestinal symptoms by avoiding FODMAP-containing foods, such as onions, pulses, and products made from wheat or rye. The downside of a low FODMAP diet is the reduced intake of dietary fiber. Applying sourdoughs—with specific FODMAP-targeting metabolic properties—to wholegrain bread making can help to remarkably reduce the content of FODMAPs in bread without affecting the content of the slowly fermented and well-tolerated dietary fiber. In this review, we outline the metabolism of FODMAPs in conventional sourdoughs and outline concepts related to fructan and mannitol metabolism that allow development of low FODMAP sourdough bread. We also summarize clinical studies where low FODMAP but high fiber, rye sourdough bread was tested for its effects on gut fermentation and gastrointestinal symptoms with very promising results. The sourdough bread-making process offers a means to develop natural and fiber-rich low FODMAP bakery products for IBS patients and thereby help them to increase their dietary fiber intake.

[2]. ”Fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) have beneficial and adverse health effects [ 1]. Oligosaccharides that are not hydrolyzed and absorbed in the small intestine are rapidly fermented by intestinal microbiota in the terminal ileum and the proximal colon [2, 3]. Diverse FODMAPs that are fermented by intestinal microbiota consistently cause adverse symptoms when a dose of about 0.3 g/kg body weight, corresponding to about 15 g/day, is exceeded [4 ,5 ]. Adverse symptoms include osmotic diarrhea, intestinal distension, and bloating [5,6 ]. The extent of the adverse symptoms decreases with the degree of polymerization because of the reduced osmotic load of oligosaccharides in the small intestine, and the reduced rate of fermentation [6]. Adverse effects are not described for non-digestible polysaccharides, which are fermented at a much lower rate [7]. Microbiota in the terminal ileum include proteobacteria and lactic acid bacteria as the dominant representatives; ileal microbiota effectively ferment mono- and disaccharides but typically lack extracellular enzymes for hydrolysis of higher oligosaccharides and polysaccharides [ 6]. The sensitivity of individuals to adverse symptoms caused by FODMAPs is highly variable; adverse symptoms are often linked to irritable bowel syndrome (IBS). The sensitivity to gas pressure and pain varies highly among individuals; moreover, intestinal microbiota adapt toward the fermentation of specific oligosaccharides; this adaptation reduces or eliminates adverse symptoms [8]. Many FODMAPs are conditionally digestible depending on the genetic status of the host. About 35% of humans are lactase-persistent and digest lactose while lactose is a non-digestible Foods 2018, 7, 96 2 of 12 FODMAP in the remainder of the population [ 9]. A substantial proportion of humans are fructose intolerant; the proportion of fructose intolerant individuals among patients with IBS was reported to be over 60% [10 , 11]. Fructose absorption is highly dependent on the presence of equimolar amounts of glucose as uptake from the small intestine uses the same transport channels [10 ]. A rare variation in the sucrose-isomaltase gene reduces the digestibility of sucrose, including sucrose in the FODMAPs; this genetic variant also predisposes for IBS [12]. Health beneficial or prebiotic effects of oligosaccharides relate to the bacterial conversion of oligosaccharides to short chain fatty acids [1 ,13 ]. These short chain fatty acids increase the energy harvest from carbohydrates that escape small intestinal hydrolysis and absorption, improve intestinal
barrier properties and resistance to enteric infections, and exert systemic effects related to inflammation, cognitive functions, and behavior through specific recognition with G-protein coupled receptors (for reviews, see [ 1 ,7 ,13 ]). Of note, oligomeric fructans, for which health beneficial prebiotic effects were most consistently demonstrated [13 ], appear also of particular concern for adverse effects in IBS [ 6]. Adverse and beneficial effects of FODMAPs are thus interconnected and partially related to the same mechanisms, bacterial fermentation. Consequently, a reduction of adverse symptoms in IBS by a low FODMAP diet also increased the luminal pH and reduced the abundance of bifidobacteria and butyrate-producing colonic bacteria [ 14 ,15 ]. While the term FODMAPs indiscriminately includes all oligosaccharides, different compounds were reported to have divergent effects. Supplementation of
a low FODMAP diet with β-galacto-oligosaccharides was reported to improve IBS symptoms relative to a low FODMAP diet [ 16 ]. In other words, replacement of FODMAPs with different categories of FODMAPs may improve symptoms of IBS without the adverse consequences of a low fiber diet [1]. Wheat and rye are major contributors to the dietary intake of low molecular weight fructans [ 17] but whole grain products also are major contributors to the intake of dietary fiber [7 ]. Fermentation processes during baking may allow conversion or degradation of FODMAPs without reducing the overall dietary fiber content of bread [ 18]. This review aims to summarize current knowledge on the use of conventional and sourdough baking in the production of low FODMAP bread.”

Parole chiave: lievito madre; FODMAP; fruttano; mannitolo; lattobacilli; sindrome dell’intestino irritabile (IBS); intolleranza al grano non celiacaNote

Note
“Gli oligosaccaridi, i disaccaridi, i monosaccaridi e i polioli fermentabili (FODMAP) hanno effetti benefici e negativi sulla salute [ 1]. Gli oligosaccaridi che non vengono idrolizzati e assorbiti nell’intestino tenue vengono rapidamente fermentati dal microbiota intestinale nell’ileo terminale e nel colon prossimale [2, 3]. Diversi FODMAP fermentati dal microbiota intestinale causano costantemente sintomi avversi quando viene superata una dose di circa 0,3 g/kg di peso corporeo, corrispondente a circa 15 g/giorno [4,5]. I sintomi avversi includono diarrea osmotica, distensione intestinale e gonfiore [5,6]. L’entità dei sintomi avversi diminuisce con il grado di polimerizzazione a causa del ridotto carico osmotico degli oligosaccaridi nell’intestino tenue e della ridotta velocità di fermentazione [6]. Gli effetti avversi non sono descritti per i polisaccaridi non digeribili, che vengono fermentati a una velocità molto inferiore [7]. Il microbiota nell’ileo terminale include proteobatteri e batteri dell’acido lattico come rappresentanti dominanti; il microbiota ileale fermenta efficacemente mono- e disaccaridi ma in genere manca di enzimi extracellulari per l’idrolisi di oligosaccaridi e polisaccaridi superiori [6]. La sensibilità degli individui ai sintomi avversi causati dai FODMAP è molto variabile; i sintomi avversi sono spesso legati alla sindrome dell’intestino irritabile (IBS). La sensibilità alla pressione del gas e al dolore varia notevolmente da individuo a individuo; inoltre, il microbiota intestinale si adatta alla fermentazione di specifici oligosaccaridi; questo adattamento riduce o elimina i sintomi avversi [8]. Molti FODMAP sono condizionatamente digeribili a seconda dello stato genetico dell’ospite. Circa il 35% degli esseri umani è persistente alla lattasi e digerisce il lattosio, mentre il lattosio è un FODMAP non digeribile nel resto della popolazione [9]. Una parte sostanziale degli esseri umani è intollerante al fruttosio; la percentuale di individui intolleranti al fruttosio tra i pazienti con IBS è risultata essere superiore al 60% [10, 11]