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.

The retrogradation kinetics of starches of different botanical origin in the presence of glucose syrup.

The influence of glucose syrup on the retrogradation of cereal starches was investigated. Laboratory isolated starches from wheat (WS) and oats (OS - oat starch and ROS - residual oat starch) were used in this research. ROS was isolated from the flour left after the industrial separation of ß-glucans. Gelatinization temperature of oat starches (63.82°C and 64.01°C for OS and ROS, respectively) was higher than for WS (62.26°C), whereas gelatinization enthalpy for oat starches (8.87J/g and 9.09J/g for OS and ROS, respectively) was lower than for WS (9.99J/g). Moreover, retrogradation percentage (%R) was similar for both oat starches (29.76% and 27.72% for OS and ROS, respectively), and was substantially lower than for WS (42.04%). The introduction of glucose syrup into system reduced the extent of the retrogradation. Rate of the process was suppressed for WS and ROS, whereas for OS it was increased. ß-Glucan production process had no significant effect on the gelatinization and retrogradation of oat starch.

Oat raw materials and bakery products - amino acid composition and celiac immunoreactivity.

BACKGROUND: The aim of this study was to compare the biochemical and immunochemical properties of avenins in some special oat raw materials and additionally the possibility of using them as a raw material for the gluten-free bakery products. METHODS: The compared oat raw materials were - oat flakes, commercial oat flours (including gluten-free oat flour) and residual oat flour, which is by-product of ß-glucan preparation. Biochemical characteristic included amino acid compositions and SDS-PAGE profiles of extracted avenins. The immunochemical reactivity with polyclonal anti-gluten and monoclonal anti-gliadin antibodies was evaluated qualitatively and quantitatively by immunoblotting and ELISA methods. Additionally, experimental bakery products made of examined raw materials were assessed according to their suitability for the celiac patients' diet. RESULTS: The highest protein content was measured in the ß-glucan preparation "Betaven" and gluten-free oat flour. Proteins of all materials are rich in glutamic and aspartic acid, leucine and arginine. Proportions of amino acids in avenins extracted from most of oat raw materials are similar, excluding gluten-free oat flour, which has a very low avenin content and proportions of individual amino acids are different. The SDS-PAGE protein pattern consisted of proteins with molecular weight of about 25-35 kDa. Polyclonal anti-gluten anti-body recognized all protein fractions of molecular weight higher than 20 kDa. Quantitative ELISA analysis shows that the majority of samples has a gliadin-like protein content within the range of 80-260 mg/kg, excluding gluten-free flours and corresponding bakery products. Altogether, ß-glucan preparation has extremely high level of gliadin-like proteins. CONCLUSIONS: In the examined oat raw materials and foods the contents of immunoreactive amino acid sequences exceeded the limit of 20 mg/kg (considered as gluten-free) except for gluten-free flours (oat and  the prepared mixture) and the bakery products based on gluten-free flours. Unfortunately, the rest of oat raw materials and products cannot be considered gluten-free.

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.

Quality of gluten-free supplemented cakes and biscuits.

Gluten-free confectionery products were used as controls for comparison with the products, which included different supplements such as linseed meal, amaranth and/or buckwheat. The latter were expected to increase nutritional values of confectionery products. Cookies were analyzed in terms of volume, selected textural parameters (hardness, cohesiveness), organoleptic quality, shelf-life, and different chemical components. All supplemented gluten-free products received high consumer scores, exceeding in some cases those of control samples. Supplementation of gluten-free confectionery products with linseed meal, amaranth and/or buckwheat flours enhanced their final nutritional quality. A significant rise was observed in the protein content and dietary fiber, and in the case of linseed meal also alpha-linolenic acid. All of the supplemented gluten-free confectionery products contained more macro-elements and micro-elements (i.e. potassium, phosphorus, magnesium, calcium, iron, manganese, zinc and copper), as compared with the controls. Taking into account the amino-acid composition, amaranth proved a more beneficial supplement of gluten-free products than linseed.