Non-Saccharomyces yeasts Lachancea thermotolerans and Schizosaccharomyces pombe mixed cultures applications in wine food safety (biogenic amines and ethyl carbamate control) from high pH grape juice

The classical way to make red wine is based on the use of Sacharomyces cerevisiae yeasts during alcoholic fermentation and Oenococus oeni bacteria during malolactic fermentation.  This traditional winemaking methodology produces commercial stable red wines from a microbiological point of view. However, this methodology when it is applied in grape juices with high pH, like it is common in the south of Spain, can produce high levels of biogenic amines and ethyl carbamate that can seriously influence human health. This work explains the use of a new red winemaking biotechnology that uses the combination of Lachancea thermotolerans and Schizosaccharomyces pombe yeasts as an alternative to the conventional alcoholic and malolactic fermentations. Schizosaccharomyces pombe consumes malic acid while Lachancea thermotolerans produces lactic acid in order to avoid an unnecessary deacidification in low acidic musts from warm viticulture areas such as the south of Spain. This methodology also reduces some malolactic fermentation hazards for human health such as biogenic amines and ethyl carbamate

Combine use of Selected Schizosaccharomyces pombe and Lachancea thermotolerans Yeast Strains as an Alternative to the Traditional Malolactic Fermentation in Red Wine Production

Most red wines commercialized in the market use the malolactic fermentationprocess in order to ensure stability from a microbiological point of view. In this secondfermentation, malic acid is converted into L-lactic acid under controlled setups. Howeverthis process is not free from possible collateral effects that on some occasions produceoff-flavors, wine quality loss and human health problems. In warm viticulture regions suchas the south of Spain, the risk of suffering a deviation during the malolactic fermentationprocess increases due to the high must pH. This contributes to produce wines with highvolatile acidity and biogenic amine values. This manuscript develops a new red winemakingmethodology that consists of combining the use of two non-Saccharomyces yeast strains asan alternative to the traditional malolactic fermentation. In this method, malic acid is totallyconsumed by Schizosaccharomyces pombe, thus achieving the microbiological stabilizationobjective, while Lachancea thermotolerans produces lactic acid in order not to reduce andeven increase the acidity of wines produced from low acidity musts. This technique reducesthe risks inherent to the malolactic fermentation process when performed in warm regions.The result is more fruity wines that contain less acetic acid and biogenic amines than thetraditional controls that have undergone the classical malolactic fermentation

Rhizoctonia solani as causative agent of damping off of Swiss chard in Europe

During September 2011, post-emergence damping off of Swiss chard (Beta vulgaris subsp. cicla L.) was observed in a greenhouse in Villa del Prado (Spain). About 20% of the seedlings showed damping off symptoms. Lesions were initially water soaked, dark brown necrosis of crown tissue, irregular in shape and sunken in appearance on large plants, causing the infected seedlings to collapse and eventually die. Rhizoctonia solani was isolated consistently from symptomatic plants. After morphological and molecular identification of the isolates, pathogenicity was tested by placing agar plugs of four isolates adjacent to the stem at the three or four true leaf stage. In inoculated plants, brown crown and stem necrosis occurred while control plants did not show disease symptoms. Pathogenicity using non-germinated seeds was also tested. All four isolates produced extensive damping off when inoculated on non-germinated seeds. To our knowledge, this is the first report of damping off of Swiss chard caused by R. solani in Europe

Selected yeast strains (Saccharomyces cerevisiae) with glycolytic inefficiency and metabolic inhibitors to reduce alcoholic degree in vines from warm regions

n warm regions potential alcoholic degree and unequilibrated must, especially in acidity are real problems to be resolved. Strains of Saccharomyces cerevisiae have different yields to produce ethanol from the same content of sugars. These peculiarities can be named glycolytic inefficiencies. We can select yeast strains with these properties in order to reduce the final alcoholic degree together with the production of some metabolic intermediates that can have repercussion in the sensorial profile like polyalcohols or organic acid

The effects of storage duration, temperature and cultivar on the severity of garlic clove rot caused by Fusarium proliferatum.

Diseases that affect garlic during storage can lead to severe economic losses for farmers worldwide. One causal agent of clove rot is Fusarium proliferatum. Here, the progress of clove rot caused by F. proliferatum and its dependence on different storage conditions and cultivar type were studied. The effect of temperature on mycelial growth, conidial viability, and fungal survival during garlic commercial storage was documented. Samples of 50 bulbs from a randomized field trial with three different clonal generations for purple garlic (F3, F4 and F5) and the F4 clonal generation for white garlic were labeled and stored for two months (short-term storage). In addition, another sample of the F5 clonal generation of purple garlic was stored for 6 months after harvest (long-term storage). The presence of the pathogen and the percentage of symptomatic cloves were evaluated. A notable difference in the rot severity index (RSI) of different garlic varieties was observed. In all studied cases, clove rot increased with storage time at 20 ◦ C, and the white garlic variety had a higher index of rot severity after two months of storage. Additionally, there were clear differences between the growth rates of F. proliferatum isolates. Studies conducted on the temperature responses of the pathogen propagules showed that expo- sure for at least 20 min at 50 ◦ C was highly effective in significantly reducing the viability of fungal conidia. Pathogenicity studies showed that the fungus is pathogenic in all commercial varieties. However, there were significant differences in varietal susceptibility between Chinese and white garlic type cultivars (81.84 ± 16.44% and 87.5 ± 23.19% symptomatic cloves, respectively) and purple cultivars (49.06 ± 13.42% symptomatic cloves

Reduction of 4-ethylphenol concentration using lyophilized yeast biomasses as bioadsorbent: influence on the anthocyanin contents and chromatic parameters

A new investigation trend, based on the parietal adsorption activity showed by yeast cellwalls, opens up the possibility to use yeast lees or derived products like inactive dry yeast preparations to reduce 4-ethylphenol concentrations in wines. These type of natural products entails an interesting eco-friendly alternative to common physical treatments. In this work the bioadsorption capacity of 4-ethylphenol of different wine yeast biomasses have been studied -Saccharomyces cerevisiae G37 and Schizosaccharomyces pombe 936-, in order to diminish the negative impact on the sensorial profile of this type of compound (Figure 1). the repercussions of this palliative treatment over the chromatic properties and anthocyanin concentration have also been studied by means of UV-Vis and HPLC-PDAD/ESI-MS analysi

Identifying yeats belonging to the Brettanomyces/Dekkera genera through the use of selective-differential media

The purpose of this work was to compare and optimise different selective and differential media to aid in isolating spoilage yeasts belonging to the Brettanomyces/Dekkera genera. Growth media containing selective and differential factors were employed. These were inoculated with strains of yeast representing Spanish oenological microbiota. Lastly, some of these isolation media were successfully applied in 24 types of wine with a high ethylphenol content, all of which were from the Haro Oenological Station (La Rioja, Spain). p-coumaric acid was determined using High performance liquid chromatography-photodiode-array detection-electrospray ionization mass spectrometry (HPLC-DAD-ESI/MS); 4-ethylphenol by using Solid phase micro extraction-gas chromatography-mass spectrometry (SPME-GC-MS); and the rest of the analysis was carried out using official OIV methodology. Actidione is the most effective selective factor for isolating Brettanomyces/Dekkera yeast genera. Other secondary selective factors (selective carbon sources, sorbic acid and ethanol as a microbicide agent) may be used successfully to eliminate potential false positivities; however, they slow growth and delay the time to obtain results

Selección Saccharomyces cerevisiae con baja producción de etanol para control del grado alcohólico en zonas cálidas

En la enología española existen muchas regiones en las que el clima favorece maduraciones sacarimétricas excesivas lo que supone que durante la fermentación se alcancen grados alcohólicos elevados. La levadura metaboliza el azúcar (glucosa y fructosa) por vía fermentativa produciendo como productos mayoritarios etanol y CO2. Sin embargo, no todas las levaduras alcanzan el mismo grado alcohólico para un mosto con una concentración de azúcares igual. Normalmente las variaciones son pequeñas y se relacionan con desviaciones del metabolismo glicolítico hacia otras moléculas que pueden ser interesantes desde el punto de vista sensorial (Figura 1). Este tipo de levaduras permiten controlar el grado alcohólico excesivo a la vez que pueden favorecer la formación de metabolitos que incrementen la complejidad sensorial de los vinos. En este trabajo se han estudiado 25 levaduras seleccionadas para la elaboración de vinos tintos en distintas DOs españolas para evaluar su eficiencia glicolítica y por tanto el grado alcohólico alcanzado por cantidad de azúcar metabolizada para seleccionar levaduras que permitan reducir el grado alcohólico

Physiological features of Schizosaccharomyces pombe of interest in the making of white wines

This work studies the physiology of Schizosaccharomyces pombe strain 938 in the production of white wine with high malic acid levels as the sole fermentative yeast, as well as in mixed and sequential fermentations with Saccharomyces cerevisiae Cru Blanc. The induction of controlled maloalcoholic fermentation through the use of Schizosaccharomyces spp. is now being viewed with much interest. The acetic, malic and pyruvic acid concentrations, relative density and pH of the musts were measured over the entire fermentation period. In all fermentations in which Schizo. pombe 938 was involved, nearly all the malic acid was consumed and moderate acetic concentrations produced. The urea content and alcohol level of these wines were notably lower than in those made with Sacch. cerevisiae Cru Blanc alone. The pyruvic acid concentration was significantly higher in Schizo. pombe fermentations. The sensorial properties of the different final wines varied widely

Reducción de etilfenoles por formación de piranoantocianos vinilfenólicos

Los géneros Brettanomyces/Dekkera son responsables de la aparición de aromas fenólicos [Figura 1]. Dichos olores son resultado de la evolución de ácidos hidroxicinámicos hacia etilfenoles como consecuencia de las actividades hidroxicinamato descarboxilasa (HCDC) y vinilfenolreductasa (VphR) de estos géneros [Figura 2]. El objetivo del trabajo fue facilitar la formación de piranoantocianos vinilfenólicos usando cepas de Saccharomyces HCDC+ (pero VphR-) , con objeto de reducir el contenido inicial de ácidos hidroxicinámicos del vino durante la fermentación y prevenir de esta forma la formación de etilfenoles en caso de contaminación por Brettanomyces/Dekkera