Carotenoids are part of a diverse group of isoprenoid compounds. Due to the many properties they possess, they may become an alternative to synthetic additives in various industrial sectors. The increase in consumer demand and awareness determines research into extracting them from plants, algae and microorganisms. The extraction of carotenoids from plants is an inefficient method and generates additional production costs. On the other hand, the carotenoid potential of microorganisms, especially among yeasts, has not been fully exploited. The diversity of yeast species and strains influences the extraction of many fractions of carotenoids, including the less known ones such as thorulene and tholuradine. The developed adaptability of yeast enables the optimisation of their culture, which facilitates the understanding of their metabolic pathways. At the same time, the coordination of carotenoid and lipid synthesis may prevent their degradation or the loss of their bioactive properties. Application research has been conducted mainly in the feed industry, where their colouring and antimicrobial or immunomodulating properties are used. In the medical and pharmaceutical fields, there is not much research due to safety restrictions and the necessity of the high purity of the fractions. This review also highlights the overlooked aspect of carotenoids’ biodegradability, which is required to exploit the bioactive properties of microbial carotenoids.

The aim of this research was to create a plant-based beverage based on seeds of sunflower (Helianthus annuus), pea (Pisum sativum) and runner bean (Phaseolus multiflorus). The selection of the ingredients was based on the main objective to obtain the nutritional value and sensory characteristics of a formed product similar to cow’s milk. The ingredient proportions were created by comparing the protein, fat and carbohydrate content of seeds versus cow’s milk. Due to the observed low long-term stability of plant-seed-based drinks, a water binding guar gum, a thickener in the form of locust bean gum and gelling citrus amidated pectin containing dextrose were added and evaluated as functional stabilisers. All of the designed and created systems were subjected to selected methods of characterisation of the most important final product properties, such as rheology, colour, emulsion and turbidimetric stability. Rheological analysis confirmed the highest stability of the variant supplemented with 0.5% guar gum. Both stability and colour measurements indicated the positive characteristics of the system supplemented with 0.4% pectin. Finally, the product with 0.5% guar gum was identified as the most distinctive and similar vegetable drink to cow’s milk.

The microbiological quality of feed is affected by a range of factors throughout the food chain. The aim of this study was to analyze the effect of feed storage conditions on its microbiological quality. Poultry feeds were sampled in three periods: winter, summer and autumn from four domestic farms. At the same time, air temperature and humidity, as well as indoor microbiological air quality were measured. The transfer of contaminants from the air to feed that was not properly protected was demonstrated. Contamination of feed with fecal bacteria occurred regardless of the animals access to feed stores. The study showed the influence of indoor conditions on air and feed contamination. In winter and autumn, where high air humidity (>51%) was recorded, higher concentrations of total yeast and mold counts were isolated for feed 2 in winter and feed 1 in autumn in the inverted rooms. Only in winter was there a correlation between the physical parameters of the air samples. The effect of temperature on the microbiological quality of feed was determined only during the autumn period.

Introduction: Carotenoids are a diverse group of pigmented isoprenoid compounds. They are now commercially extracted mainly from plants or by a chemical synthesis, from which 80-90 % of compounds are obtained. However, synthetic carotenoids, if provided in huge amounts, can be harmful to human health, whereas waste generated in their production process poses an environmental risk. An alternative to the equivalent of a chemical synthesis is to use microbial production to obtain carotenoids with a high biological activity, which could be a natural and functional additive in various industries. Therefore, the aim of the study was to optimize the culture conditions and biosynthesis of selected carotenoid fractions by Rhodotorula strains. Yeast culture was developed in 100 cm3 flasks in which 50 cm3 of YPG medium was prepared with constant shaking and access to light. The regulation of carotenoid biosynthesis took into account the influence of the following factors: temperature, pH and a carbon/nitrogen ratio. A spectrophotometric method was used to determine the fraction of carotenoids in terms of quantity and quality. Results and conclusions: The effects of temperature, C/N ratio and pH on the amount of biomass obtained were demonstrated. Changing pH conditions determined significant differences in the determined carotenoid fractions regardless of a strain. Moreover, the application of extreme pH values did not inhibit the growth or synthesis of carotenoids, pointing to the adaptation of Rhodotorula sp. to stressful environmental conditions. A variable increase in biomass of the strains tested was found depending on the culture conditions, which affected the logarithmic growth curve of the yeast. An analysis of the influence of physicochemical factors allowed for the identification of culture conditions favorable for carotenoid production.

Carotenoids are a diverse group of isoprenoid compounds found in nature. As natural pigments and bioactive compounds, carotenoids are used in various industries as functional additives. The increasing knowledge about the disadvantages of synthetic carotenoid production has drawn attention to the potential of carotenogenic yeasts and the use of food industry waste. This study analyzed the potential of post-fermentation waste from fermented quinoa production as a culture medium. For this purpose, reference yeast strains and strains isolated from various environments were used. The C:N ratio in the waste used was determined, and then the yeast was cultured in waste medium with the isolated strains and in a mixed culture with L. plantarum, using three culture variants. In subsequent stages, carotenoid powder was produced, and the carotenoid content, antioxidant capacity, and FTIR spectrum distribution were determined. The studies confirmed the possibility of using plant ferments as culture media. The extraction of powder enabled the concentration of carotenoids, obtaining the highest total fraction of carotenoids (TFC) for strains R-1 (2.85 mg/g d.w.) and R-2 (3.05 mg/g d.w.). FTIR spectra confirmed the presence of functional groups found in β-carotene standards in the resulting powders. At the same time, the obtained formulate exhibited bioactive properties by binding DPPH oxygen free radicals at a level of 66.80–78.05%.