Bread Dough Fermentation Research Articles

A new acoustic technique to monitor bread dough during the fermentation phase

The fermentation phase represents one of the most important stages in the bread-making process and its characterization is therefore necessary to control and improve the quality of the final product. However, the methods used for the characterization of this phase are limited by the lack of investigation techniques considering the complexity of the medium at this stage due to its instability and to the presence of gas bubbles. In this work, we propose a low frequency acoustic technique to characterize this complex phenomenon. With this aim in view, a measuring device was designed, through which the possibility of monitoring, non-destructively, the kinetics of bread dough fermentation was validated in order to study the influence of various technological parameters such as temperature and the different ingredients.

Study of the behaviour of Lactobacillus plantarum and Leuconostoc starters during a complete wheat sourdough breadmaking process

The acidification properties, metabolic activity and technological performance of four individual Lactobacillus plantarum or Leuconostoc freeze-dried starters were investigated during a complete wheat sourdough breadmaking process including 0.2 g/100 g baker's yeast. Microbiological contents (lactic acid bacteria and yeasts), acidification characteristics (pH and total titratable acidity), soluble carbohydrates (maltose, glucose and fructose) and fermentative end-products (lactic and acetic acids, ethanol) contents were evaluated during both sourdough and corresponding bread dough fermentation. Biochemical and technological analysis of the resulting bread products are also presented. Some differences among strains in acidification properties and soluble carbohydrates availability were outlined both in sourdough and bread dough. Each individual Leuconostoc or Lb. plantarum starter was able to produce a characteristic fermentation and was found to ensure the production of breads with overall satisfactory acceptance.

Dynamic magnetic resonance microscopy of flour dough fermentation.

Magnetic resonance microscopy was carried out at 9.4 T with a voxel volume of 117 x 117 x 500 microm(3) and temporal resolution was adjusted to 8.5 min for a dynamic follow-up of bread dough fermentation during 2 h at a constant temperature of 30 degrees C. An image analysis procedure based on gray levels mathematical morphology routines was performed to assess bubble distribution and cell wall thickness inside the imaged bread dough. The evolution of the extracted curves allows one to characterize quantitatively the amount of bubbles and their growth. Using this procedure, different bread doughs were examined to determine the impact of dough composition on the structure modification during fermentation.

On-line observation of dough fermentation by magnetic resonance imaging and volumetric measurements

The fermentation of bread and cake dough was monitored on-line by two types of volumetric measurements and by magnetic resonance imaging (MRI). The volumetric measurements enabled independent determination of the actual dough volume and the amount of carbon dioxide that permeated out of the dough. MRI allowed us to obtain an insight into the developing dough and to observe the pore structure during proofing. Due to the non-destructive and non-invasive character of the methods, no sample preparation was necessary, and the fermentation process was not influenced by the measurements. Both methods provided results that were in accordance with each other. The data were used to derive formal reaction-kinetic data for the course of the fermentation process in bread and cake doughs.

Effect of Yeast Extracts Containing Propionic Acid on Bread Dough Fermentation and Bread Properties

ABSTRACT: Three commercial yeast extracts (Oxoid, Champlain, Lallemand) fermented with immobilized cells of Propionibacterium freudenreichii were added in broths and bread formulations, and their effect on growth and gas production by bakers yeast was determined. Appearance and preservation of the breads were examined. There was significantly more gas produced by the yeast when fermented yeast extracts were added to the dough. In broths, the initial growth rate was slower with media containing fermented yeast extract when compared to their unfermented equivalents. Loaves formulated with propionic acid of the fermented yeast extract contained less ethanol. Paired t‐tests showed that breads formulated with fermented yeast extract were protected for a longer period against mold than those that contained non‐fermented yeast extract.

Sodium Gluconate and Potassium Gluconate as Substitutes for Sodium Chloride in Breadmaking.

Sodium gluconate (Na-gluconate) and potassium gluconate (K-gluconate) were used as NaCl substitutes in breadmaking to determine their potential usefulness in preparing reduced-sodium bread and non-sodium bread. Replacement of 75% of the NaCl by Na-gluconate and of 50% by K-gluconate had no effect on rheological properties of dough as measured by Brabender Extensograph. Replacement of 100% of the NaCl by either Na-gluconate or K-gluconate resulted in decreased resistance to extension, but the decreased resistance to extension had no effect on dough handling properties. Expansion of white bread dough (5% sugar, flour weight basis) increased with the proportion of NaCl replaced by Na-gluconate or K-gluconate. The patterns of carbon dioxide production during fermentation of non-sugar bread dough showed that as the proportion of Na-gluconate or K-gluconate increased, the time required to complete fermentation decreased, and the fermentation pattern showed a gradual resemblance to that seen in non-sugar bread dough without NaCl. In white bread, complete replacement of NaCl (2%, flour weight basis) by Na-gluconate or K-gluconate did not cause a difference in loaf volume, nor did it have any significant effect on overall desirability. Shelf life of white bread was not affected by substitution of Na-gluconate or K-gluconate for NaCl. Based on these results, it is possible to make reduced-sodium bread using Na-gluconate, and non-sodium bread using K-gluconate, incorporating each gluconic acid salt in an amount equal to 1.8% of flour weight in white bread.

Amino Acid Metabolism by Yeasts and Lactic Acid Bacteria during Bread Dough Fermentation

ABSTRACTMetabolism of 22 free amino acids (AA) during fermentation(early and later steps) of wheat dough samples started with pure and associated cultures of yeast and lactic acid bacteria, and commercial compressed yeast (CY) were investigated. Unfermented and fermented straight doughs were studied byReversed‐Phase HPLC of their dansyl derivatives. Used as starters were strains of Saccharomyces cervisiae, Lactobacillus brevis, Lactobacillus plantarum and Enterococcus faecium. Statistical data analysis indicated clustering of samples with yeast and samples without yeast (including uninoculated doughs) respectively, based on rate of metabolism of acidiC., basiC., aliphatic and aromatic A A. Differences in AA metabolism during the later fermentation step (DF2) categorized bacterial starters into groups according to balance between degree of assimilation(D F2<0) and exoproteolytic release(DF2>0) of amino acids.

Low Molecular Weight Peptides of Bread Dough and Bread. Dynamics During Fermentation and Baking

Abstract Dynamics in low molecular weight peptides (LMWP) during wheat bread dough fermentation and baking have been investigated by comparing the amino acid composition and the partial N-terminal amino acid sequence of the LMWP fraction of purified acetic acid extracts from unfermented, 2.5 hour-, and 24 hour-fermented straight doughs, and bread. Nutritional requirements on LMWP of yeast and lactic acid bacteria starting the fermentation are only evidenced when aspartic acid and asparagine levels are reduced. Specific endo and exoproteolytic activities releasing basic and hydrophobic nitrogen chains along breadmaking process, as well as level of hydrophylic residues in unfermented doughs affect browning and bread flavor.

Biochemical evolution of nitrogen compounds during fermentation of wheat bread doughs containing pure cultures of lactic acid bacteria

The metabolic activities of three species of lactic acid bacteria (Lactobacillus brevis, L. plantarum andStreptococcus faecium) during wheat bread dough fermentation have been investigated by evaluating the biochemical changes which occur in 0.85 mol/L NaCl-soluble nitrogen components in unfermented, 4-h and 24-h fermented straight doughs. Non-protein nitrogen compounds increase during a 24-h-fermentation period in all doughs. Exoproteolytic activity is denoted mainly inL. plantarum fermented doughs by an important rise in the free amino acids. Doughs containingL. brevis show a larger production of peptides over a 24-h fermentation period and strong nutritional requirements on low-molecular-weight peptides are evidenced byStreptococcus faecium over short fermentation periods. Progressive depletion in the polypeptides and protein contents as well as a decrease in the estimated protein chain length over the fermentation period forL. plantarum andSt. faecium containing doughs are evidence of endoproteolytic activities in the high-molecular-weight soluble components. An increase in the size of the protein fragments released in the 4-h fermented doughs containingL. brevis denotes enzymatic hydrolysis on non-soluble protein chains.