• Energy Research

Over the last few years, the selection of autochthonous strains of Saccharomyces cerevisiae as wine starters has been studied; however, researchers have not focused on the ability to remove ochratoxin A (OTA) as a possible trait to use in oenological characterization. In this article, a polyphasic approach, including yeast genotyping, evaluation of phenotypic traits, and fermentative performance in a model system (temperature, 25 and 30°C; sugar level, 200 and 250 g liter(-1)), was proposed as a suitable approach to select wine starters of S. cerevisiae from 30 autochthonous isolates from Uva di Troia cv., a red wine grape variety grown in the Apulian region (Southern Italy). The ability to remove OTA, a desirable trait to improve the safety of wine, was also assessed using enzyme-linked immunosorbent assay. The isolates, identified by PCR-restriction fragment length polymorphism analysis of the internal transcribed spacer region and DNA sequencing, were differentiated at strain level through the amplification of the interdelta region; 11 biotypes (I to XI) were identified and further studied. Four biotypes (II, III, V, VIII) were able to reduce OTA, with the rate of toxin removal from the medium (0.6 to 42.8%, wt/vol) dependent upon the strain and the temperature, and biotypes II and VIII were promising in terms of ethanol, glycerol, and volatile acidity production, as well as for their enzymatic and stress resistance characteristics. For the first time, the ability of S. cerevisiae to remove OTA during alcoholic fermentation was used as an additional trait in the yeast-selection program; the results could have application for evaluating the potential of autochthonous S. cerevisiae strains as starter cultures for the production of typical wines with improved quality and safety.

AbstractThe aim of this work was to study Saccharomyces cerevisiae strains isolated from vineyards of the autochthonous grape variety “Uva di Troia” located in different geographical areas of Apulian region (Southern Italy). Four hundred isolates were studied in relation to H2S production, β‐glucosidase activity, and pigments adsorption from grape skin. Thus, 81 isolates were selected, identified through the amplification of the interdelta region, and grouped in 19 biotypes (from I to XIX). The enological performances were assessed to determine the content of residual sugars, ethanol, glycerol, and volatile acidity, after a microfermentation in Uva di Troia must for each isolate. The ability to remove ochratoxin A (OTA) was studied as an additional tool to select promising strains. A geographical‐dependent technological variability was found for glycerol and volatile acidity, suggesting that the different indigenous yeasts can have a peculiar impact on the final characteristics of the corresponding wine (“Nero di Troia”). Only 2 biotypes (VI and XVII) were able to remove OTA throughout fermentation, with the highest reduction achieved by the biotype XVII (ca. 30%).

AbstractBACKGROUNDThis study investigated the effect of some physicochemical parameters on the removal of ochratoxin A (OTA) by yeasts.RESULTSTwo wild strains of Saccharomyces cerevisiae (W47 and Y28) were used to assess OTA removal under various conditions of temperature, pH, ethanol content and incubation time. All samples were analysed for OTA concentration by enzyme‐linked immunosorbent assay (ELISA). In addition, yeast oenological traits were investigated: qualitative and technological traits were assessed on appropriate laboratory media, while the main products of microfermentation (sugars, ethanol, glycerol, acetic acid) were evaluated by Fourier transform infrared spectroscopy (FTIR). The results showed OTA reduction by 36–42% in cultures containing 100 g L−1 ethanol incubated at pH 3.5 and 37 °C.CONCLUSIONOTA removal was affected by contact time, pH and ethanol content, as it was increased at low pH and by 100 g L−1 ethanol. Moreover, the phenomenon was reversible, as OTA was lowest after 4 days, then it was partially released in the medium. © 2012 Society of Chemical Industry

The aim of this research was to study the effect of time, temperature, sugar content and addition of diammonium phosphate (DAP) on ochratoxin A (OTA) removal by two strains of Saccharomyces cerevisiae using a completely randomized design.The strains were grown in a medium containing OTA (2 μg l(-1)), two sugar levels (200 and 250 g l(-1)), with or without DAP (300 mg l(-1)), and incubated at 25-30°C. The yeasts were able to decrease the toxin amount by c. 70%, with the highest removing effect observed after 3 days at 30°C in the presence of 250 g l(-1) of sugars and with DAP; after 10 days, the toxin was partially released into the medium. The strains produced high ethanol and glycerol contents, showed high tolerance to single/combined stress conditions and possessed β-d-glucosidase, pectinase and xylanase activities.Ochratoxin A removal was affected by time, temperature, sugar and addition of DAP. Moreover, the phenomenon was reversible.Ochratoxin A removal could be an interesting trait for the selection of promising strains; however, the strains removing efficiently the toxin could release it back; thus, the selection of the starter should take into account both the removal and the binding ability of OTA.

The sustainability of fishery is a global challenge due to overfishing and reduced stocks all over the world; one of the leading factors of this threat is fish loss/waste. As a contribution to the global efforts towards a sustainable world, this review addresses the topic from different sides and proposes an overview of biorefinery approaches by discussing bioactive compounds that could be produced from fish loss (nitrogen compounds, lipids, minerals and pigments, and fish-based compounds such as chitosan). The second part of this review reports on the possibility of using loss or unwanted fish to design products for human consumption or for animal feeding, with a focus on economic criteria, consumers’ segmentation, and some examples of products. The final focus is on Food and Agriculture Organization FAO guidelines as a roadmap for the future with respect to solving this threat by addressing the problem from different sides (technology, skills, market, policy, social and gender equity, and infrastructures).