Degradation of HMW Glutenins During Wheat Sourdough Fermentations

Loponen, Jussi; Mikola, Markku; Katina, Kati; Sontag‐Strohm, Tuula; Salovaara, Hannu

doi:10.1094/cchem.2004.81.1.87

Cited by 91 publications

(72 citation statements)

References 24 publications

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“…This is reflected by the considerable levels of maltose retrieved after each fermentation step and an increase of total amino acids upon fermentation (27,39,40,69). The present study showed that the competitiveness of sourdough LAB is enhanced by both the use of the arginine deiminase pathway (in an early stage) and the use of alternative electron acceptors.…”

Section: Discussionmentioning

confidence: 55%

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

Meulen

Scheirlinck

Schoor

et al. 2007

Appl Environ Microbiol

188

149

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Four laboratory sourdough fermentations, initiated with wheat or spelt flour and without the addition of a starter culture, were prepared over a period of 10 days with daily back-slopping. Samples taken at all refreshment steps were used for determination of the present microbiota. Furthermore, an extensive metabolite target analysis of more than 100 different compounds was performed through a combination of various chromatographic methods including liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. The establishment of a stable microbial ecosystem occurred through a three-phase evolution within a week, as revealed by both microbiological and metabolite analyses. Strains of Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus rossiae, Lactobacillus brevis, and Lactobacillus paraplantarum were dominating some of the sourdough ecosystems. Although the heterofermentative L. fermentum was dominating one of the wheat sourdoughs, all other sourdoughs were dominated by a combination of obligate and facultative heterofermentative taxa. Strains of homofermentative species were not retrieved in the stable sourdough ecosystems. Concentrations of sugar and amino acid metabolites hardly changed during the last days of fermentation. Besides lactic acid, ethanol, and mannitol, the production of succinic acid, erythritol, and various amino acid metabolites, such as phenyllactic acid, hydroxyphenyllactic acid, and indolelactic acid, was shown during fermentation. Physiologically, they contributed to the equilibration of the redox balance. The biphasic approach of the present study allowed us to map some of the interactions taking place during sourdough fermentation and helped us to understand the fine-tuned metabolism of lactic acid bacteria, which allows them to dominate a food ecosystem.Sourdough is a mixture of ground cereals (e.g., wheat or rye) and water that is spontaneously fermented. Sourdough fermentations improve dough properties, enhance both bread texture and bread flavor, and delay bread spoilage (28). Lactic acid bacteria (LAB) and yeasts play a key role in sourdough fermentation processes (9,21,26,28,29,55). Sourdough LAB have been intensively studied with respect to their carbohydrate metabolism (16,24,60), proteolysis and amino acid metabolism (16,23,58,69), lipid metabolism (16), and production of volatile compounds (7,31,32). Besides these general metabolic traits, specific metabolic properties have been recognized in sourdough LAB, such as the use of alternative electron acceptors (59, 61), the production of antifungal compounds (38,45,57), the biosynthesis of exopolysaccharides (36, 63, 64), and arginine catabolism (8, 53). These metabolic traits of sourdough LAB highlight their adaptation to the sourdough environment. For instance, fructose-to-mannitol and arginineto-ornithine conversion favor ATP generation and/or acid stress (16). Also, interactions between sourdough LAB and yeasts have been studied in detail (9, 21).The microbial growth and activity of LAB in so...

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Section: Discussionmentioning

confidence: 55%

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

Meulen

Scheirlinck

Schoor

et al. 2007

Appl Environ Microbiol

188

149

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“…Second, proteolytic activity in aseptic doughs and sourdoughs was inhibited upon the addition of an aspartic protease inhibitor, indicating that cereal proteinases are responsible for the first step in gluten degradation. Aspartic protease inhibitors but not serine proteinase inhibitors were previously reported to inhibit proteolytic activities in sourdough extracts (22). Third, screening the genome of L. sanfranciscensis strain DSM 20451 did not provide evidence for a prt-like proteinase.…”

Section: Discussionmentioning

confidence: 88%

“…proteolytic activity in sourdough extracts is inhibited by aspartic protease inhibitors but not by serine protease inhibitors (22). Thus, the most active proteases in wheat sourdoughs are the cereal aspartic proteinases whereas serine proteinases from lactobacilli play a minor role only (34).…”

mentioning

confidence: 96%

Functional Characterization of the Proteolytic System ofLactobacillus sanfranciscensisDSM 20451^Tduring Growth in Sourdough

Vermeulen

Pavlovic

Ehrmann

et al. 2005

Appl Environ Microbiol

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Protein hydrolysis and amino acid metabolism contribute to the beneficial effects of sourdough fermentation on bread quality. In this work, genes of Lactobacillus sanfranciscensis strain DSM 20451 involved in peptide uptake and hydrolysis were identified and their expression during growth in sourdough was determined. Screening of the L. sanfranciscensis genome with degenerate primers targeting prt and analysis of proteolytic activity in vitro provided no indication for proteolytic activity. Proteolysis in aseptic doughs and sourdoughs fermented with L. sanfranciscensis was inhibited upon the addition of an aspartic protease inhibitor. These results indicate that proteolysis was not linked to the presence of L. sanfranciscensis DSM 20451 and that this strain does not harbor a proteinase. Genes encoding the peptide transport systems Opp and DtpT and the intracellular peptidases PepT, PepR, PepC, PepN, and PepX were identified. Both peptide uptake systems and the genes pepN, pepX, pepC, and pepT were expressed by L. sanfranciscensis growing exponentially in sourdough, whereas pepX was not transcribed. The regulation of the expression of Opp, DtpT, and PepT during growth of L. sanfranciscensis in sourdough was investigated. Expression of Opp and DtpT was reduced approximately 17-fold when the peptide supply in dough was increased. The expression of PepT was dependent on the peptide supply to a lesser extent. Thus, the accumulation of amino nitrogen by L. sanfranciscensis in dough is attributable to peptide hydrolysis rather than proteolysis and amino acid metabolism by L. sanfranciscensis during growth in sourdough is limited by the peptide availability.Wheat sourdough fermentation has a positive influence on the overall bread quality because it improves flavor (14,29,32) and texture (18) and prolongs shelf life due to the formation of antifungal compounds (20) and delayed staling (6). The fate of the protein fraction of the flour during sourdough fermentation is of crucial importance for bread quality. The protein network in wheat doughs determines dough rheology, gas retention, and thus bread volume and texture. Proteolytic events during fermentation provide the substrates for microbial growth and conversion of amino acids to flavor precursor compounds and antifungal metabolites (20,32). Furthermore, some peptides from wheat proteins are involved in human cereal intolerance and their levels in bread hydrolysates are reduced by selected sourdough lactic acid bacteria (9).The most abundant proteins in wheat flour are gluten proteins. After dough mixing, the proteins are linked to each other by disulfide and hydrogen bonds, resulting in an insoluble network with a molecular weight of up to several million (35). Proteolytic enzymes in the flour are associated with wheat gluten. The pH-optimum of activity of these aspartic proteinases is below 4.0 (2, 3). Accordingly, the proteolytic activity in wheat doughs is strongly increased in acidified doughs independent of the presence of lactic acid bacteria (32, 33) and prote...

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“…In the present study, the focus was on processed breads, since food processing may alter the solubility of prolamins, e.g. the denaturation caused by heating decreases the solubility of the proteins, whereas the depolymerization of glutenins increases their solubility in aqueous alcohols (Loponen et al 2004). In addition, the formation of gluten network during mixing and baking induces changes in the extractability of wheat prolamins.…”

Section: Discussionmentioning

confidence: 99%

Improved extraction of prolamins for gluten detection in processed foods

Kanerva¹,

Sontag‐Strohm²,

Brinck³

2008

AFSci

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A problem in gluten analysis has been inconsistent extractability of prolamins, particularly from processed foods consisting of unknown portions of prolamins from wheat, barley, and rye. This study aimed at improving the extraction of prolamins for immunological analysis, regardless of the cereal species and the production process. The prolamins were extracted with varying concentrations of ethanol, 1-propanol, and 2-propanol. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting were applied to study the protein composition of the extracts and the antibody recognition of the prolamin subgroups. We characterized the affinities of prolamin-specific antibodies that are used in gluten analysis against the prolamin groups that were soluble in 40% 1-propanol. The antibody R5 recognized more abundantly the medium-molecular weight groups, including polymeric proteins, and less the high-molecular weight groups than the anti-ω-gliadin antibody. In the present study, the prolamins were most efficiently extracted by 40% 1-propanol with 1% dithiothreitol at 50 °C . The prolamins were extracted from processed bread samples with efficiency similar to that from untreated meal samples.

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Degradation of HMW Glutenins During Wheat Sourdough Fermentations

Cited by 91 publications

References 24 publications

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

Functional Characterization of the Proteolytic System ofLactobacillus sanfranciscensisDSM 20451^Tduring Growth in Sourdough

Improved extraction of prolamins for gluten detection in processed foods

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Degradation of HMW Glutenins During Wheat Sourdough Fermentations

Cited by 91 publications

References 24 publications

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

Population Dynamics and Metabolite Target Analysis of Lactic Acid Bacteria during Laboratory Fermentations of Wheat and Spelt Sourdoughs

Functional Characterization of the Proteolytic System ofLactobacillus sanfranciscensisDSM 20451Tduring Growth in Sourdough

Improved extraction of prolamins for gluten detection in processed foods

Contact Info

Product

Resources

About

Functional Characterization of the Proteolytic System ofLactobacillus sanfranciscensisDSM 20451^Tduring Growth in Sourdough