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.

Aroma forming volatiles are important components of fermented beverages. The aim of current research is to evaluate the influence of different yeast strains on the volatile compounds of fermented apple juice of the variety ‘Lietuvas Pepins’. Apples were harvested in the Latvia State Institute of Fruit Growing. Apple variety ‘Lietuvas Pepins’ juice was fermented with four different commercial yeast strains - Saccharomyces bayanis yeasts ‘EC-1118’, ‘Cider yeast’, Saccharomyces cerevisiae yeasts ‘71B-1122’ and ‘K1V- 1116’. Fermentation was performed in laboratories of Latvia University of Agriculture, Faculty of Food Technology. Volatile aroma compounds of apple juice, yeasts and fermented juice were determined. Extraction of aroma compounds was performed using solid phase microextraction (DVB/Car/PDMS fibre). Analysis of volatile aroma compounds was made using a Perkin Elmer Clarus 500 GC/ MS. The data obtained in the present study shows the influence of the yeast strain on the final chemical and volatile composition. The main group of volatiles in juice was esters, whereas in fermented juices – alcohols. The highest percentage of esters was determined in juice fermented with ‘Cider yeast’ whereas the highest percentages of alcohols – in juice fermented with yeast K1V-1116 and also free terpenes, associated with the floral note. The 71B-1122 strain produced the highest amount of identified volatile compounds. The strains potentially producing a higher number of volatile compounds could contribute to a more complex aroma of the final product, due to their potential ability to utilize and transform numerous apple must precursors.

The aroma of coffee is the main quality factor. Compounds with floral, fruity, citrus and sometimes fermented aroma notes are defined as high quality characteristics for the specialty coffee brew. Commercial coffees mostly are at medium roast and the aroma profile is focused on balanced chocolate, caramel, toasted bread and almond bitterness aroma notes. These sensory characteristics set the focus for volatile compound profile analysis by Headspace solidphase microextraction (HS-SPME). The most popular fibres for commercial coffee aroma profile analysis are DVB/ CAR/PDMS, CAR/PDMS, PDMS/DVB and PA. There is limited research done about specialty coffee aroma profile and evaluation of more suitable fibres for solid-phase microextraction. The aim of the research is to evaluate the aroma composition of specialty coffee brews using different SPME fibres. Results demonstrated that CAR/PDMS fibre, compared to other fibres, can extract significantly more volatile compounds with higher peak areas in all chemical compound groups, except phenols. The CAR/PDMS was the only fibre which could detect all 17 important volatile compounds for specialty coffee. In conclusion, from the given research evidence, CAR/PDMS fibre is suggested as the most suitable SPME fibre coating for volatile compound extraction for specialty coffee brew import. The result provides evidence for improved specialty coffee aroma profile analysis by SPME.

Specialty coffee, according to Specialty Coffee Association of America (SCAA) standards, is coffee which has been standardized from the coffee plantation process until its delivery to the consumer, in compliance with all quality standards, to highlight the characteristics of the beverage. With increasing coffee consumption, more attention is focused not only on the flavour and texture of the drink, but also on the impact of coffee on health. The beneficial effects of coffee on human health are mainly based on a wide range of biologically active components. The coffee composition of the biologically active compounds and flavour compounds are influenced differently by almost all technological processes. The aim of this review was to summarize recent scientific developments about composition of aroma, flavour and biologically active compounds in specialty coffee and evaluate the best possibilities to balance health promoting and flavour attributes. Specialty coffee mainly focuses on fruity, floral, sweet and acidic notes in coffee, which are opposite to phenolic compound aroma characteristics during roasting process. In conclusion, roasting temperature significantly influences all biologically active compounds and important aroma, flavour volatiles in coffee. All compound concentration, except coffee melanoidins, decreases during roasting process. Light-medium roast level could provide stability among floral, fruity aroma, flavour notes and biologically active compounds (phenolic compounds and coffee melanoidins) in coffee.

During processing of aromatized rapeseed oils, volatiles from the added spices migrate in oil and give specific taste and aroma to oils, but there are no investigations about volatile compound migration in oil. The aim of this research was to determine volatile compounds in oils aromatized with basil, oregano, and thyme. In basil 43 volatile compounds, in oregano - 39, and in thyme - 37 volatile compounds were identified. In oil aromatized with basil - 8, in oil aromatized with oregano - 20, and in oil aromatized with thyme 11 volatile compounds were identified. From the total amount of identified compounds in spices, 23-30% of volatiles found in thyme migrated in oil aromatized with thyme, from oregano in oil migrated 12-15% of volatiles, but from basil in oil aromatized with basil - only 5% of volatiles. More volatile compounds as camphene, alpha-pinene, and alpha-thujene migrate in oil better than less volatile compounds like methyl chavicol, and thymal. Migration of the same compound in oil from various spices differed. It could be explained by the location of the volatile compound in plant structure.

Kvass is a non-alcoholic beverage produced by fermenting kvass mash with yeast; alcohol content in kvass must be less than 1.2% by volume. Kvass extracts have longer shelf-life and they are essentially free of ethanol. The aim of this research was to evaluate and compare aroma compounds in naturally fermented kvass and kvass extracts. Experiments were carried out at the Latvia University of Agriculture, Department of Food Technology from November 2014 to February 2015. Three commercially available kvass samples (Bruveris, Bauskas and Liepkalni) were used to produce kvass extracts applying vacuum evaporation. The investigation of volatile compounds in kvass and kvass extracts was performed using solid phase microextraction and gas chromatography mass spectrometry. Dry matter content in kvass extracts was 32.4 ± 0.3% (ISO 2173:2003). In all kvass and extract samples in total 25 volatile compounds were detected. Ten of them were esters, five alcohols, five acids, four aldehydes and three ketones. Such aroma compounds as ethyl acetate (fruity flavour), hexyl acetate (fruit, herb) and ethyl decanoate (grape) were found only in Bruveris kvass, 2,3-butanedione (buttery) and phenethyl butyrate (floral) were found only in Bauskas alus kvass and three volatile compounds were identified only in Liepkalni kvass – acetic acid (sour), furfuryl alcohol (burnt) and carvone (caraway). Less than a half of the main aroma volatiles in kvass were also identified in kvass extracts and total values of peak areas were significantly lower in kvass extracts compared to kvass (p = 0.01).