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Red yeasts grow on food wastes, show antagonistic activity against food-spoilage microorganisms, produce food supplements, and may be utilized as feed-supplements themselves to positively modulate the quali-quantitative composition of intestinal microbiota. Therefore, they show a variety of possible biotechnological applications in agri-food-related processes. Here, to further explore the biotechnological potential of red yeasts, eleven strains ascribed to different species of the genera Rhodotorula and Sporobolomyces, differing for biomass and carotenoids production, were characterized in vitro for biofilm formation, invasive growth, and growth at the temperature range of 20–40 °C and in vivo for their antagonistic activity against the fungal pathogen and patulin producer Penicillium expansum. Most of them formed cellular MAT and showed invasive growth as well as adhesion to plastic materials. Four strains determined a significant reduction of fruit decay caused by P. expansum on apple fruit while the remaining seven showed different degrees of biocontrol activity. Finally, none of them grew at body temperature (>37 °C). Statistical analyses of both qualitative and quantitative phenotypic data, including biomass and carotenoids production, gathered further information on the most interesting strains for the biotechnological exploitation of red yeasts in agri-food-related process.

In Mediterranean countries, and in Sardinia in particular, durum wheat is traditionally used for bread production and modern cultivars have gradually replaced the use of old landraces due to the poor technological quality of the latter. However, recent escalation in customer demand for old varieties thanks to an appreciation of their nutritional properties, as well as ecological issues, has led to the need for technological improvements able to enhance the rheological performance of the old varieties to support their diffusion. The aim of this study was to assess whether the baking performance of an Old Italian wheat cultivar, Russello wheat, could be improved through the addition of different hydrocolloids (methylcellulose, guar, psyllium, xanthan and tara). The effects of two different concentrations (0.5% and 1%) of each hydrocolloid on the rheological properties, pasting, fermentation and microstructural properties of dough were assessed, and the results compared with those obtained using a modern durum wheat cultivar flour. Significant differences were found in the dough obtained with hydrocolloids. In particular, dough extensibility was increased with 1% psyllium or xanthan gum, whereas the gas retention coefficient was increased with all hydrocolloids. The pasting properties were modified via an increase in the final viscosity and setback value compared with control semolina (with the exception of methylcellulose); this resulted in a more homogeneous dough structure with a compact appearance and the absence of any deep interruptions in the gluten network as revealed by scanning electron microscopy.

Many foods and beverages in temperate and tropical regions are prone to contamination by ochratoxin A (OTA), one of the most harmful mycotoxins for human and animal health. Aspergillus ochraceus and Aspergillus carbonarius are considered among the main responsible for OTA contamination. We have previously demonstrated that four low or non- fermenting yeasts are able to control the growth and sporulation of OTA-producing Aspergilli both in vitro and on detached grape berries: the biocontrol effect was partly due to the release of volatile organic compounds (VOCs). Aiming to further characterise the effect of VOCs produced by biocontrol yeast strains, we observed that, beside vegetative growth and sporulation, the volatile compounds significantly reduced the production of OTA by two A. carbonarius and A. ochraceus isolates. Exposure to yeast VOCs also affected gene expression in both species, as confirmed by downregulation of polyketide synthase, non-ribosomal peptide synthase, monooxygenase, and the regulatory genes laeA and veA. The main compound of yeast VOCs was 2-phenylethanol, as detected by Headspace-Solid Phase Microextraction-Gas Chromatography-Tandem Mass Spectrometry (HS-SPME-GC?MS) analysis. Yeast VOCs represent a promising tool for the containment of growth and development of mycotoxigenic fungi, and a valuable aid to guarantee food safety and quality. This publication was made possible by NPRP grant # 8-392-4-003 from the Qatar National Research Fund (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors. We acknowledge constructive comments provided by anonymous reviewers. Scopus

Grape juice can be easily contaminated with ochratoxin A (OTA), one of the known mycotoxins with the greatest public health significance. Among the different approaches to decontaminate juice from this mycotoxin, microbiological methods proved efficient, inexpensive and safe, particularly the use of yeast or yeast products. To ascertain whether immobilisation of the yeast biomass would lead to successful decontamination, alginate beads encapsulating Candida intermedia yeast cells were used in our experiments to evaluate their OTA-biosorption efficacy. Magnetic calcium alginate beads were also prepared by adding magnetite in the formulation to allow fast removal from the aqueous solution with a magnet. Calcium alginate beads were added to commercial grape juice spiked with 20μg/kg OTA and after 48h of incubation a significant reduction (>80%), of the total OTA content was achieved, while in the subsequent phases (72–120h) OTA was slowly released into the grape juice by alginate beads. Biosorption properties of alginate-yeast beads were tested in a prototype bioreactor consisting in a glass chromatography column packed with beads, where juice amended with OTA was slowly flowed downstream. The adoption of an interconnected scaled-up bioreactor as an efficient and safe tool to remove traces of OTA from liquid matrices is discussed. This publication was made possible by NPRP grants # NPRP 4-259-2-083 and # NPRP 8-392-4- 003 from the Qatar National Research Fund (a member of Qatar Foundation).