Yeast plays a key role in the production of fermented foods and beverages, such as bread, wine, and other alcoholic beverages. They are able to produce and release from the fermentation environment large numbers of volatile organic compounds (VOCs). This is the reason for the great interest in the possibility of adapting these microorganisms to fermentation at reduced temperatures. By doing this, it would be possible to obtain better sensory profiles of the final products. It can reduce the addition of artificial flavors and enhancements to food products and influence other important factors of fermented food production. Here, we reviewed the genetic and physiological mechanisms by which yeasts adapt to low temperatures. Next, we discussed the importance of VOCs for the food industry, their biosynthesis, and the most common volatiles in fermented foods and described the beneficial impact of decreased temperature as a factor that contributes to improving the composition of the sensory profiles of fermented foods.

The potato is a crop of global importance for the food industry. This is why effective protection against pathogens is so important. Fungi as potato pathogens are responsible for plant diseases and a significant reduction in yields, as well as for the formation of mycotoxins. This study focuses on the effect of three natural biocides, yeast Metschnikowia pulcherrima, lactic acid bacteria Lactiplantibacillus plantarum, and aqueous garlic extract, on the improvement of the physiology of planted potato tubers and the reduction in mycotoxin formation. The secondary metabolites produced by the fungal pathogens of genera Fusarium, Alternaria, Colletotrichum, Rhizoctonia, and Phoma in the presence of these biocontrol agents were compared to profiles obtained from contaminated potatoes. Analysis of liquid chromatography coupled with tandem mass spectrometry data showed the presence of 68 secondary metabolites, including the mycotoxins: alternariol, alternariol methyl ether, altertoxin-I, aurofusarin, beauvericin, diacetoxyscirpenol, enniatin B, and sterigmatocystin. The studies showed that the applied biocontrol agents had a positive effect on the physiological parameters of potatoes (including root growth, stem growth, gas exchange, and chlorophyll content index) and on the reduction in the production of mycotoxins and other secondary metabolites by Fusarium, Alternaria, and Phoma.

More than 40 yeast strains were isolated from various types of plant biomass and then evaluated for potential applications in biotechnological processes conducted at low temperature. Adaptation to low temperature was tested by passaging the isolates at decreasing temperatures, from 30 to 15 °C. Only the strains that were able to adapt to the final temperature and reached the stationary growth phase relatively quickly were submitted to further experimentation. These included eight environmental yeast isolates from four types of materials of plant origin: wheat, rye, and cucumber, containing glucose, fructose, sucrose, and starch; yeast-fermentable sugars; red beetroot, containing large amounts of glucose and fructose; and fruits (grapes and apples) containing glucose, fructose, and sucrose. The strains were identified and then subjected to a series of experiments to assess their suitability for use in low-temperature biotechnological industrial processes incorporating microbial biomass. The growth dynamics and assimilation profiles of the yeast strains were investigated, as well as their ability to produce volatile compounds.

Rapeseed meal (RM) is produced in large quantities as a byproduct of oil extraction from rapeseeds. However, the efficient utilization of RM as animal feed is limited by its low metabolizable energy, poor palatability, and high levels of fiber and anti-nutritional components. Here, we investigate the potential of enriching RM with single-cell protein through fermentation with conventional and unconventional yeasts. The process of simultaneous saccharification and fermentation improved the parameters of the waste biomass, especially the protein content, while reducing the amount of crude fiber and enhancing the biotransformation of isoflavone compounds present in the waste. Fermentation yielded the highest protein gain for the Saccharomyces cerevisiae Ethanol Red strain (ΔN = 2.38%) at a biomass load of 12.5 g and for Scheffersomyces stipitis (ΔN = 2.34%) at an enzyme dose of 0.125 mL/10 g DM. The crude fiber content (CF) was reduced by 2.55–7.18%. The simultaneous saccharification and fermentation (SSF) process resulted in the conversion of isoflavones to forms with fewer adverse effects and a lower estrogenic activity. The results show the potential of using RM as a substrate for making a nutritionally improved feed components.

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