In Latvia the spontaneous sourdough is used in traditional rye bread baking whose microflora is determined in flour and in microorganism cultures presented in external environment. Almost all spontaneous sourdough cultures, especially those that have been maintained for a long time, contain both lactic acid bacteria (LAB) and yeasts. The main purpose of the current research was to analyze growth dynamics of LAB in spontaneous rye flour sourdough and to isolate some of its representatives. Experiments were carried out in the Department of Food Technology of the Faculty of Food Technology of Latvia University of Agriculture in January and February 2008. Considering differences in constituents, two types of flour were used in the research - peeled and crude rye flour. There were three stages of spontaneous sourdough preparation in 72 hours totally; the renewal of sourdough was realized each 24 hours. The dynamics of LAB plate count in every stage of fermentation was investigated as well as changes of pH was observed using standard methods. The results of experiments show substantial increase in amount of LAB in both sourdoughs, particularly in sourdough from peeled flour, reaching 6.06 log10 cfu mlE-1. A significant decrease of pH value from pH 6.7 to pH 3.8 during fermentation process was observed. As a result, the sourdough from peeled flour had desirable properties for preparation of sourdough starter. LAB cultures isolated and identified from current sourdoughs using API tests: Lactobacillus brevis and Lactobacillus fermentum are also typical members of sourdoughs found in other countries.

Triticale is an amphidiploid hybrid between wheat and rye having protein-rich grain. For expanding the range of bakery and pastry production in the world there are being developed various recipes for product enriching with fibre, especially b-glucan, proteins, vitamins and other nutrients for a healthier diet. It can be done making a flour blend from whole grain triticale, rye, hull-less barley, rice and maize flour. The aim of research was to evaluate the rheological properties of dough made from different cereals flour and flour blends. Whole grain flour of triticale, rye, hull-less barley, rice, maize and flour blends were used in this research. Flour blends were made from triticale in a combination with other flour (whole grain rye, hull-less barley flour, rice and maize flour) in various proportions. Wheat flour (Type 405) was used as a control. Rheological properties of mixed flour dough were studied using Farinograph (Brabender Farinograph-AT, GmbH and Co. KG, Germany). Moisture content of flour and flour blends was determined using AACC method 44-15A. Water absorption and dough development time decrease, but dough stability, time of breakdown and farinograph quality number increases, increasing proportion of other flour in triticale flour. The flour blends need less time for dough development comparing with triticale flour. Enriching triticale flour with whole grain rye, whole grain barley, rice and maize flour in various proportions made triticale flour dough more rheologically stable during mixing.

Taste, smell and the flavour are the most important attributes determining the quality of bread or baked cereal products in general. Bread flavour is composed of hundreds of volatile and non-volatile compounds, i.e. many alcohols, ketones, aldehydes, acids, esters and other compounds. Many researchers have been studying volatile compounds in different breads worldwide, but in Latvia only few studies are conducted on volatile compounds in bread and its production stages. The aim of this research was to analyse the composition of volatile compounds during wheat dough fermentation. Experiments were done in 2011 and carried out in the Laboratory of Bread Technology and Laboratory of Packing Material Investigations at the Department of Food Technology in the Latvia University of Agriculture. An investigation of volatile compounds was done using solid-phase microextraction (SPME) and gas-chromatography mass-spectrometry (GC-MS). Volatile compounds were analyzed on the 10th, 20th and 30th minutes of wheat dough fermentation. In a fermentation process of wheat dough totally 15 volatile compounds were detected. Eight of them were alcohols, two aldehydes, two ketones, one ester, one acid and one terpene. Three volatile compounds – 1-octanol, caryophyllene and acetophenone, were detected in the dough samples only after 30 minutes of fermentation – those were not detected at the earlier stages of fermentation. The peak areas of 11 volatile compounds increased, but peak area of one volatile compound decreased along the fermentation time. The study proved that solid-phase microextraction can be used for detection of volatile compounds in wheat dough fermentation process.

This work deals with the baking quality of the spelt wheat grain (Triticum spelta L.) compared with bread wheat (Triticum aestivum L.). Mixed flours were made of different share of spelt wheat and bread wheat (in total 11 mixtures) in 2016 in the Česke Budejovice in the laboratories of the Faculty of Agriculture. The technological quality of these mixtures was analysed, focusing on standard evaluation methods (protein content, characteristic of gluten or swellability of protein). The analysis was supplemented by complete rheological analysis made by Mixolab II. Bread was used as a model product. Subsequently, sensory evaluation of baked bread from the previously prepared mixtures was done. Part of the analysis was to estimate the economic basic bread recipe with different proportions of bread wheat and spelt wheat. The results were statistically analysed via STATISTICA 9.1 (StatSoft, Inc., USA). It was proved that the flour made of spelt can give cereal products with a higher nutritional value. The results have shown that the spelt grain is much more suitable for baking. Its advantage is the higher protein content and higher resistance of kneading of the dough and starch gelatinization rate, which was statistically confirmed. The main disadvantage is the higher price of spelt. According to the results, the ideal utilization of spelt wheat based on sensory analysis and economic calculations seems to be the mixture of spelt wheat and bread wheat, which results in an undeniable decrease of the product cost, and hence effects the common customer choice and taste preferences.

The main direction of using wheat grains is grinding them into low-extraction flours. The flours collected from individual passages differ in terms of chemical composition and physical properties, which in turn differentiates their baking value. The aim of the study was to evaluate the baking value of passage flours obtained from the milling of spring and winter wheat grain. Wheat grain was milled in a 6-pass laboratory mill MLU-202 by Bühler. The baking value of the obtained passage flours was evaluated by an indirect method (protein content, gluten content and quality, falling number, farinograph analysis) and by a direct method (by baking and performing quality evaluation of the obtained bread). The research showed that the efficiency of flours from individual milling passages varied. The passages flours differed significantly in terms of chemical composition and baking value. The highest flour yields were obtained from the first and second grinding stages, while the smallest from the third grinding stage. Ash and total protein content, flour water absorption, and amylolytic enzymes activity increased together with the subsequent milling stage in both reduction-passage and grinding-passage. The gluten content increased with the next reduction stage, while it decreased with the subsequent grinding passage. The bread from the laboratory baking test was diversified in terms of sensory characteristics, loaf volume, and crumb porosity. The best quality bread was obtained from flour from the first two reduction passages. The lowest quality bread was obtained from flour from the final grinding passage.

Germinated grains are added to wheat dough with the purpose to promote the biological value of bread. As a result, a new product was obtained with a higher content of protein, fibre, B group vitamins; and vitamins C and E. The task was to investigate gluten quality changes at grain germination time, wheat dough rheological properties changes with various wheat, rye and barley amount additions, germinated for a different time. With the purpose to save maximum stability value of gluten, it was ascertained that the germination time of wheat grain could not be more than 24 hours. The best dough quality was obtained with germinated wheat grain additive. Germinated rye and barley grain additive (more than the experimentally ascertained amount) increases dough softening, decreases dough development time and dough stability. Only adding experimentally determined optimal amount of germinated grain, which promotes high quality bread, could produce dough with accepted rheological properties.

The major wheat flour constituent, which determines the dough quality, is gluten. Oatmeal has higher biological value due to amino acid composition and content if compared to other cereals, but the technological properties of proteins are not as good as the ones of wheat flour. Oat products can be used in bread making although the increased amount of additives shows negative influence on bread texture, elasticity, volume, taste, and flavour. The method is developed for hydrolysed oatmeal separation in soluble and insoluble fractions, thus extending the oatmeal application possibilities. The aim of the current research was the investigation of influence of hydrolysed oats insoluble fraction on wheat dough rheological properties. The obtained results proved that in case hydrolysed oats insoluble fraction additive was used, water adsorption was increased by 63.8%-66.4% and dough stability time was changed from 4.8 to 10.0 min. The negative influence on dough development time and dough softening degree was observed. The farinograpgh quality index was within acceptable limits (less than 120 FU), if the oat additive of 10% and 15% was used. It is possible to obtain dough with better rheological properties if the hydrolysed oats insoluble fraction additive is 15% from flour mass.

Whole grain flour can be considered as a good candidate for pasta fortification due to the health benefits. Literature reports pasta dough fortification with non-traditional ingredients and cereals. Therefore, the purpose of the current research was to investigate rheological properties of whole grain flour blends for pasta production. Flour blends were made from wheat flour (type 405) in a combination with other flours (whole grain wheat, rye or hull-less barley flour) in various proportions (from 10% to 50%). Wheat flour type 405 was used as a control. Rheological properties of dough were analysed using Farinograph AT (Brabender, GmbH and Co.KG., Germany) and starch gelatinization properties of flour starch using Amylograph-E (Brabender GmbH and Co.KG., Germany); moisture content of flour samples (AACC 44-15A from 2000). The results of present research demonstrate that rheological properties of dough decrease if the amount of whole grain flour in blend increases. It was concluded that water absorption and dough development time of dough with whole grain flour blends addition is less than the parameters of control wheat flour (type 405). However, a higher starch gelatinization was obtained for flour blends with whole wheat grain flour, comparing to blends with whole rye and hull-less barley grain flour, which mainly could be explained with a higher gluten content of whole wheat grain flour.