The Influence of Arabinoxylan of Different Molar Masses on the Properties of Rye Bread Baked by the Postponed Baking Method.

Rye grain is a good source of dietary fiber, phenolic compounds, vitamins, and mineral compounds. To prevent the staling process of bread, semi-finished bakery products are subjected to cooling or freezing, and this process is called the postponed baking method. The aim of this study was to examine the influence of rye arabinoxylans differing in molar mass on the properties of rye bread baked using the postponed baking method. The breads were baked from rye flour types 720 and 1150, without and with a 1% share of unmodified or cross-linked rye arabinoxylans (AXs). The molar mass of the unmodified AXs was 432,160 g/mol, while that of the AXs after cross-linking was 1,158,980 g/mol. The results of this study show that the 1% share of AXs significantly increased the water addition to both types of rye flour and dough yield, and this increase was proportional to the molar mass of the AXs used. It is shown that a 1% share of both AX preparations positively increased the volume and crumb moisture of bread baked by the postponed baking method. Cross-linked AXs proved to be particularly effective in increasing the volume and bread crumb moisture. Both AX preparations had a positive effect on reducing the bread crumb hardness of rye breads baked by the postponed baking method.

An Attempt to Replace Pure Citric Acid with Natural Lemon Juice during Potato Starch Esterification.

The application of chemical operations in food processing, in which pure chemical compounds are used to modify food ingredients, often raises social concerns. One of the most frequently modified dietary substances is starch, e.g., E1401-E1404, E1412-E1414, E1420, E1422, E1440, E1442, and E1450-E1452. An alternative solution to chemical treatments seems to be the use of raw materials naturally containing substrates applied for starch modification. Heating starch with a lemon juice concentrate can be considered a novel and effective method for producing starch citrate, which is part of the so-called "green chemistry". The modified preparations obtained as a result of potato starch esterification with natural lemon juice had a comparable degree of esterification to that of the esters produced with pure citric acid. In addition, the use of the juice doubled their resistance to amylolytic enzymes compared to the preparations made with pure acid. Replacing citric acid with lemon juice can facilitate the esterification process, and the analyzed properties of both types of modified preparations indicate that starch esters produced with pure citric acid can be successfully replaced by those produced using natural lemon juice, which may increase the social acceptance of these modified preparations.

Production of Resistant Starch by Roasting Retrograded Starch with Glucose.

Starch is a natural plant raw material applicable in many areas of industry. In practice, it is most often used in a modified form, i.e., after various treatments aimed at modifying its properties. Modifications of native starch enable producing resistant starch, which, as a prebiotic with confirmed health-promoting properties, has been increasingly used as a food additive. The present study aimed to determine the effect of roasting retrograded starch with the addition of anhydrous glucose at different temperatures (110, 130 or 150 °C) and different times (5 or 24 h) on the modified starch's properties. The results of high-performance size-exclusion chromatography coupled with refractive index detector (HPSEC/RI) analysis and the changes observed in the solubility of starch roasted with glucose in DMSO, as well as in its other properties, confirm the changes in its molecular structure, including thermolytic degradation and the ongoing polymerization of starch with added glucose.

The Influence of Arabinoxylans on the Properties of Wheat Bread Baked Using the Postponed Baking Method.

Bread is a basic element of the human diet. To counteract the process of its going stale, semi-finished bakery products are subjected to cooling or freezing. This process is called postponed baking. The aim of this work was to investigate the effect of the molar mass of rye arabinoxylans (AXs) on the properties of wheat breads baked using the postponed baking method. Breads were produced using the postponed baking method from wheat flour without and with 1 or 2% share of rye AXs clearly differing in molar masses-non-modified or modified AXs by means of partial hydrolysis and cross-linking. The molar mass of non-modified AXs was 413,800 g/mol, that of AXs after partial hydrolysis was 192,320 g/mol, and that of AXs after cross-linking was 535,630 g/mol. The findings showed that the addition of all AX preparations significantly increased the water absorption of the baking mixture, and the increase was proportional to the molar mass of AXs used as well as the share of AX preparation. Moreover, for the first time, it was shown that 1% share of partly hydrolyzed AXs, of a low molar mass, in the baking mixture had the highest effect on increasing the volume of bread and reducing the hardness of the bread crumb of bread baked using postponed baking method. It was also shown that the AXs had a low and inconclusive effect on the baking loss and moisture content of the bread crumb.

Phenolic Compounds and Antioxidant Status of Cookies Supplemented with Apple Pomace.

The post-production leftovers after the pressing of apple juice are a rich source of health-promoting compounds, which could be used in the food industry for the manufacture of dietary foods, applicable also for people with celiac disease. This raw material is currently little used, and the cost of its disposal is considerable. Therefore, an attempt was made to enrich gluten-free cookies with different proportions of apple pomace. The content of individual polyphenols determined by the UPLC-PDA-MS/MS method, basic chemical composition, physical properties of cookies with 15%, 30%, 45%, and 60% apple pomace, were evaluated. It was found that apple pomace in gluten-free cookies caused an increase in the content of phenolic acids, quercetin derivatives, flavan-3-ols and dihydrochalcones. An elevation in protein, fat, and minerals was also observed. The growing share of apple pomace caused a significant increase in the content of total fiber, soluble, and insoluble fractions, but resulted in an increase in the hardness and darkening of the cookies while reducing their volume.

Nutritional properties and amino acid profile of buckwheat bread.

The effect of replacement of wheat flour with buckwheat flour at levels of 10, 20, 30, 40, and 50% on nutritional, texture, and physicochemical characteristics of bread was studied. Among others, parameters such as amino acid profile, antioxidant properties, and inositol phosphate content were determined. Amino acid score was calculated in order to evaluate the biological value of the bread protein. The breads with buckwheat flour were characterized by significantly lower whiteness of the crumb, compared to wheat bread. A positive effect of 10, 20, and 30% buckwheat flour content on the reduction of the crumb hardness, gumminess, chewiness was observed in comparison to other bread samples. A positive effect of buckwheat flour in the amount of 10-30% on the texture parameters and slowing down the process of bread staling was observed. The antioxidant properties and inositol phosphates increased with the share of buckwheat flour in the formula. A significant increase in protein was observed in bread from 20% share of buckwheat flour. The limiting amino acid of the protein of the tested flours and breads was lysine. For wheat bread, the amino acid score was 44.71% and for those with buckwheat flour it ranged from 45.67 to 75.38%.

Effect of Long-Term Potato Starch Retention with Citric Acid on Its Properties.

The present study aimed to determine changes in the properties of starch triggered by its long-lasting (1, 2, 4, 7, 10, or 14 days) retention with citric acid (5 g/100 g) at a temperature of 40 °C. The starch citrates obtained under laboratory conditions had a low degree of substitution, as confirmed via NMR and HPSEC analyses. The prolonging time of starch retention with citric acid at 40 °C contributed to its increased esterification degree (0.05-0.11 g/100 g), swelling power (30-38 g/g), and solubility in water (19-35%) as well as to decreased viscosity of the starch pastes. Starch heating with citric acid under the applied laboratory conditions did not affect the course of DSC thermal characteristics of starch pasting. The low-substituted starch citrates exhibited approximately 15% resistance to amylolysis.

Developing lactic acid bacteria starter cultures for wholemeal rye flour bread with improved functionality, nutritional value, taste, appearance and safety.

Starter cultures composed of lactic acid bacteria (LAB) were developed based on the genotypic and phenotypic characterisation of isolates belonging to dominant groups of bacteria in spontaneous rye wholemeal sourdoughs. Combinations of strains have been evaluated on an industrial scale in the sourdough fermentation process. Wholemeal rye bread was prepared using sourdoughs obtained with 3 new starter cultures, and compared to bread made using the commercial culture (LV2). All newly developed cultures used for the preparation of wholemeal rye bread allowed to obtain better quality products as compared to the LV2 based bread. The best results were obtained when the culture containing Lactiplantibacillus plantarum 2MI8 and exopolysaccharide (EPS)-producing Weissella confusa/cibaria 6PI3 strains was applied. The addition of yeast during sourdough breads production, especially the one prepared from mentioned above starter culture, significantly improved their organoleptic properties, their volume and crumb moisture was increased, and also the crumb acidity and hardness was reduced. Fermentation of rye wholemeal dough, especially without the yeast addition, resulted in a significant reduction in the content of higher inositol phosphates as compared to the applied flour, which is associated with improved bioavailability of minerals. The results of this study prove that the investigated new starter cultures can be successfully applied in wholemeal rye bread production.

Extraction, purification and characterisation of exopolysaccharides produced by newly isolated lactic acid bacteria strains and the examination of their influence on resistant starch formation.

Exopolysaccharides (EPS) were produced by four newly isolated lactic acid bacteria strains, then further extracted, separated and characterised under standardised conditions. Using a sucrose carbon source, these LAB strains belonging to Weissella confusa/cibaria produced EPS with a dextran high molecular weight fraction. The obtained yields of EPS ranged from 3.2 g/L to 47.1 g/L and outstandingly high yields were obtained using Weissella confusa/cibaria 3MI3 isolated from spontaneous spelt sourdough. After purification the influence of EPS-dextran of molar mass 3,244,000 g/mol on resistant starch formation in wheat starch pastes and pasted samples after temperature-cycled storage was examined. Size exclusion chromatography with post-column derivatisation revealed that a 1.5% share of EPS dextran limited formation of high molar mass resistant starch in starch pastes during storage. This work provides new insight on hindering resistant starch formation by using EPS, which could be efficiently produced in sourdough, thus improving the properties of sourdough bread.

Bacterial community dynamics in spontaneous sourdoughs made from wheat, spelt, and rye wholemeal flour.

Sourdough fermentation is a traditional process that is used to improve bread quality. A spontaneous sourdough ecosystem consists of a mixture of flour and water that is fermented by endogenous lactic acid bacteria (LAB) and yeasts. The aim of this study was to identify bacterial diversity during backslopping of spontaneous sourdoughs prepared from wheat, spelt, or rye wholemeal flour. Culture-dependent analyses showed that the number of LAB (109  CFU/ml) was higher by three orders of magnitude than the number of yeasts (106  CFU/ml), irrespective of the flour type. These results were complemented by next-generation sequencing of the 16S rDNA V3 and V4 variable regions. The dominant phylum in all sourdough samples was Firmicutes, which was represented exclusively by the Lactobacillales order. The two remaining and less abundant phyla were Proteobacteria and Bacteroidetes. The culture-independent approach allowed us to detect changes in microbial ecology during the 72-hr fermentation period. Weissella sp. was the most abundant genus after 24 hr of fermentation of the rye sourdough, but as the process progressed, its abundance decreased in favor of the Lactobacillus genus similarly as in wheat and spelt sourdoughs. The Lactobacillus genus was dominant in all sourdoughs after 72 hr, which was consistent with our results obtained using culture-dependent analyses. This work was carried out to determine the microbial biodiversity of sourdoughs that are made from wheat, spelt, and rye wholemeal flour and can be used as a source of strains for specific starter cultures to produce functional bread.

Arabinoxylan-starch-protein interactions in specially modified rye dough during a simulated baking process.

The purpose of this work was to investigate the kinds of processes that occur during baking of rye dough, and also to investigate which compounds are most associated with these. The study was conducted with a specially-modified dough containing starch, arabinoxylan preparations and protein obtained from rye wholemeal. Despite the same consistency of the dough samples, their pasting and rheological properties depended on the amount of arabinoxylans and their apparent molar mass. Partial breakdown of high molar mass arabinoxylan-protein and arabinoxylan-arabinoxylan complexes during baking was confirmed in the modified doughs. Heat-induced structural changes of high molar mass complexes influenced competitive hydration among starch, arabinoxylan and protein. Partial breakdown of complexes in samples containing cross-linked arabinoxylan was associated with high degrees of starch swelling at the baking stage. Small changes in complexes during baking from samples containing hydrolysed arabinoxylan were associated with limited swelling, desirable in high-quality bread crumb formation.

Extraction and characterization of rye grain starch and its susceptibility to resistant starch formation.

The aim of this work was to isolate starch from different parts of rye grain by a traditional and newly developed enzymatic method, and to compare the physical, chemical and molecular properties of isolated starches, especially focusing on susceptibility to resistant starch (RS) formation. Enzymatic treatment provided a high yield of starch which differed in granularity depending on the parts of grain used for isolation. A share of extreme size granules in starches have a strong impact on swelling and pasting properties. The differences could be explained by molecular properties of starch fractions in the examination of which HPSEC with post-column derivatization was especially helpful showing higher dispersity and molar mass of amylose in starches obtained by the enzymatic method. The derivatized SEC profiles of RS have not been reported earlier. Starches isolated by enzymatic method with a high share of small starch granules were less susceptible to a RS formation.

Arabinoxylan-starch-protein interactions in specially modified rye dough during a simulated fermentation process.

The purpose of the work was to determine which processes occur during fermentation of rye dough beside progressive hydrolysis of biopolymers and production of gases, and also to determine which compounds are most responsible for them. The study was conducted with a specially modified dough containing starch, arabinoxylan preparations (non-modified, hydrolysed and cross-linked) and protein obtained from rye wholemeal. Despite the same consistency of the dough samples, their viscosity and values of rheological parameters depended on the amount of arabinoxylan preparations and their molecular weight. Already at the stage of mixing the dough, high molecular complexes of arabinoxylan-protein and arabinoxylan-arabinoxylan were formed. Complex formation was confirmed in the modified dough preparation with rye starch including only arabinoxylan or rye protein as well as a combination of arabinoxylan and rye protein. The highest amount and molecular dimension of complexes were found in the sample composed of starch, cross-linked arabinoxylan and rye protein.

Characterization of water and alkali extractable arabinoxylan from wheat and rye under standardized conditions.

Arabinoxylans (AXs) are an important component of wheat and rye dough. They bind water, contribute to the formation of viscous dough and improve the quality of bread. For the application of AX fractions in bread making process, it is useful to record a quality profile of wheat fractions compared to the quality profile of rye fractions under standardized conditions. In this work water and alkali extractable AX containing fractions, from wheat- and rye wholemeal, were extracted under standardized conditions and characterized. For analysis of composition, structural features, and molecular dimension a combination of chemical, physicochemical, enzymatic and chromatographic techniques was applied. The molar mass distributions obtained by means of an innovative colorimetric pentose detection in the eluted SEC fractions were comparable for all under standardized conditions extracted AXs. The determined molar masses of AXs extracted both from wheat- and from rye grain were close to 2.0 × 10(5) g/mol for water extractable AXs and 3.0 × 10(5) g/mol for alkali extractable AXs. Different susceptibility to endoxylanase treatment, having been observed as differences in the SEC profiles, may be evidence of structural differences between AXs depending on their origin. The viscosities of AX solutions were strongly influenced by their molar mass and structure; samples being less susceptible to endoxylanase provided solutions of higher viscosity.

Application of model bread baking in the examination of arabinoxylan-protein complexes in rye bread.

The changes in molecular mass of arabinoxylan (AX) and protein caused by bread baking process were examined using a model rye bread. Instead of the normal flour, the dough contained starch, water-extractable AX and protein which were isolated from rye wholemeal. From the crumb of selected model breads, starch was removed releasing AX-protein complexes, which were further examined by size exclusion chromatography. On the basis of the research, it was concluded that optimum model mix can be composed of 3-6% AX and 3-6% rye protein isolate at 94-88% of rye starch meaning with the most similar properties to low extraction rye flour. Application of model rye bread allowed to examine the interactions between AX and proteins. Bread baked with a share of AX, rye protein and starch, from which the complexes of the highest molar mass were isolated, was characterized by the strongest structure of the bread crumb.

Application of cross-linked and hydrolyzed arabinoxylans in baking of model rye bread.

The role of water extractable arabinoxylan with varying molar mass and structure (cross-linked vs. hydrolyzed) in the structure formation of rye bread was examined using a model bread. Instead of the normal flour, the dough contained starch, arabinoxylan and protein, which were isolated from rye wholemeal. It was observed that the applied mixes of these constituents result in a product closely resembling typical rye bread, even if arabinoxylan was modified (by cross-linking or hydrolysis). The levels of arabinoxylan required for bread preparation depended on its modification and mix composition. At 3% protein, the maximum applicable level of poorly soluble cross-linked arabinoxylan was 3%, as higher amounts of this preparation resulted in an extensively viscous dough and diminished bread volume. On the other hand highly soluble, hydrolyzed arabinoxylan could be used at a higher level (6%) together with larger amounts of rye protein (3% or 6%). Further addition of arabinoxylan leads to excessive water absorption, resulting in a decreased viscosity of the dough during baking and insufficient gas retention.

Rye flour enriched with arabinoxylans in rye bread making.

The aim of the study was to investigate physical and chemical properties of preparations of water soluble arabinoxylans (arabinoxylan-enriched flour) obtained by industrial method and their derivatives (obtained by hydrolysis and cross-linking of aranbinoxylans), as well as their impact on baking properties of rye flours. Additionally, these results were compared with highly purified arabinoxylans prepared by laboratory method and well characterized in the literature. Flour enriched with arabinoxylans was obtained by industrial method involving air separation of flour particles. It was characterized by 8.6% arabinoxylan content, lack of insoluble material and substantial residue (67%) of starch and dextrins. The addition of all industrial method preparations in amount of 10% (i.e. approx. 1% water soluble arabinoxylans), to rye flours resulted in an increase in water absorption, bread volume and decrease in hardness of the bread crumb and the effect was especially strong in the case of flour type 720. Due to the easiness of isolation procedure, industrial method preparation could be advised as an improver for rye bread making.