Simultaneous Inoculation of Malbec (Vitis vinifera) Musts with Yeast and Bacteria: Effects on Fermentation Performance, Sensory and Sanitary Attributes of Wines

Malolactic fermentation has important consequences for the quality of wine. The present study analyzes the effect of timing of inoculation with bacteria on the performance of alcoholic and malolactic fermentation in Malbec musts from a warm climate wine growing region during two consecutive vintages, with a specific consideration for the sensory and sanitary wine parameters. In this study traditional vinification, where malolactic bacteria were inoculated after the completion of alcoholic fermentation, was compared with a simultaneous inoculation with yeast and bacteria. The experiment was made on pilot scale which closely reproduces winery conditions. The obtained results point out that simultaneous inoculation resulted in a reduction of total time of fermentation and a better control of the malolactic fermentation due to the early dominance of a selected bacterial strain. There were no negative effects on yeast population and alcoholic fermentation performance observed. Differences between the wine sensory attributes were no significant or they were in favour of simultaneous inoculations. No statistical differences in the biogenic amine levels between different timings of inoculation were found.EEA MendozaFil: Massera, Ariel Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Soria, Adriana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Catania, Carlos Domingo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; ArgentinaFil: Krieger, Sibylle. Lallemand S.A; AlemaniaFil: Combina, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Malolactic fermentation induced by Lactobacillus plantarum in Malbec wines from Argentina

The current market requirements to obtain wines with enhanced complexity and varietal character propose the finding of new microorganisms capable of driving the malolactic fermentation (MLF) and contributing to new and distinctive sensory profiles in wines. During MLF, malic acid naturally present in the must is converted into lactic acid by a decarboxylation reaction driven by lactic acid bacteria. Recently, a new strain of Lactobacillus plantarum suitable for MLF in high-pH wines was selected. This study evaluates the capacity of the L. plantarum V22 starter culture to complete MLF at laboratory and semi-industrial scale in different Malbec musts from Argentina. Malbec musts were co-inoculated with S. cerevisiae D254 and L. plantarum V22 to conduct alcoholic fermentation and MLF respectively. Two groups of Malbec musts were identified according to the ability of L. plantarum to consume malic acid. A first group, called “High Feasibility for MLF”, is characterised by the high viability of L. plantarum and the completion of MLF. On the other hand, a second group was identified, termed “Partial Feasibility for MLF”, and is characterised by a decreased viability of L. plantarum and incomplete MLF. This study shows that the capacity of L. plantarum to conduct MLF in Malbec musts is dependent on must composition, further suggesting that the evolution of pH during the fermentation process, rather than initial pH, is a critical factor affecting the successful completion of MLFEEA MendozaFil: Lerena, Marí­a Cecilia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sari, Santiago Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina.Fil: Mercado, Laura Analia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rojo, Marí­a Cristina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Combina, Mariana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mendoza; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Krieger-Weber, Sibylle. Lallemand S.A.; Alemani

Utjecaj simultane inokulacije kvascima i bakterijama na vrenje mošta sorte Malbec te na higijensku ispravnost i senzorska svojstva dobivenih vina

Malolactic fermentation has important consequences for the quality of wine. The present study analyzes the effect of timing of inoculation with bacteria on the performance of alcoholic and malolactic fermentation in Malbec musts from a warm climate wine growing region during two consecutive vintages, with a specific consideration for the sensory and sanitary wine parameters. In this study traditional vinification, where malolactic bacteria were inoculated after the completion of alcoholic fermentation, was compared with a simultaneous inoculation with yeast and bacteria. The experiment was made on pilot scale which closely reproduces winery conditions. The obtained results point out that simultaneous inoculation resulted in a reduction of total time of fermentation and a better control of the malolactic fermentation due to the early dominance of a selected bacterial strain. There were no negative effects on yeast population and alcoholic fermentation performance observed. Differences between the wine sensory attributes were no significant or they were in favour of simultaneous inoculations. No statistical differences in the biogenic amine levels between different timings of inoculation were found.Malolaktično vrenje bitno utječe na kakvoću vina. Stoga je u radu ispitan utjecaj vremena inokulacije bakterijama na alkoholno i malolaktično vrenje mošta sorte Malbec u vinogradarskoj regiji s toplim klimatom tijekom dvije uzastopne godine. Pritom su uspoređena senzorska svojstva i higijenska ispravnost vina dobivenih tradicionalnim postupkom vinifikacije (u kojem je mošt inokuliran malolaktičnim bakterijama nakon završetka alkoholnog vrenja) s onima dobivenim simultanom inokulacijom mošta kvascima i bakterijama. Pokus je proveden u pilot postrojenju koje simulira uvjete u vinariji. Dobiveni rezultati pokazuju da se simultanom inokulacijom skratilo vrijeme fermentacije i stekla bolja kontrola malolaktičnog vrenja zbog rane dominacije odabranih bakterijskih sojeva. Simultana inokulacija nije negativno utjecala na populaciju kvasca i tijek alkoholnog vrenja. Nije utvrđena statistički značajna razlika u senzorskim svojstvima ni u razini biogenih amina u vinima dobivenim različitim postupkom vinifikacije

Use of Different Nutrients to Improve the Fermentation Performances of Lactiplantibacillus pentosus OM13 during the Production of Sevillian Style Green Table Olives

The aim of this study was to evaluate the fermentation performance of the commercial starter Lactiplantibacillus pentosus OM13 with four nutrients (A, B, C, and D) that differed in the following ingredients: starch, sugars, maltodextrin, inactivated yeast, inactivated yeast rich in amino acids, inactivated yeast rich in mannoproteins, and salt (NaCl). For this purpose, six different experimental productions of Nocellara del Belice table olives were carried out. During transformation, the fermentation process was monitored by measuring pH and plate counts for lactic acid bacteria (LAB), yeasts, Enterobacteriaceae, Staphylococcaceae, and Pseudodomondaceae populations. At the end of the production process, each trial was subjected to volatile organic compound analysis and sensory evaluation. The addition of the different nutrients resulted in a significant reduction in pH (around 2.5 points) after 3 days of fermentation. At the same time, a significant increase in the number of LAB populations (> 6.6 log CFU/mL) was observed for all trials. Volatile organic compound (VOC) analysis revealed the presence of 39 compounds. In this study, nutrient C was optimal for improving the fermentation activity of L. pentosus OM13. These results provide elements for the implementation of experimental protocols to reduce product losses and improve sensory characteristics

Semen CD4+ T cells and macrophages are productively infected at all stages of SIV infection in macaques.

International audienceThe mucosal events of HIV transmission have been extensively studied, but the role of infected cells present in the genital and rectal secretions, and in the semen, in particular, remains a matter of debate. As a prerequisite to a thorough in vivo investigation of the early transmission events through infected cells, we characterized in detail by multi-parameter flow cytometry the changes in macaque seminal leukocytes during SIVmac251 infection, focusing on T cells, macrophages and dendritic cells. Using immunocytofluorescence targeting SIV proteins and real-time quantitative PCR targeting SIV DNA, we investigated the nature of the infected cells on sorted semen leukocytes from macaques at different stages of infection. Finally, we cocultured semen CD4(+) T cells and macrophages with a cell line permissive to SIV infection to assess their infectivity in vitro. We found that primary infection induced strong local inflammation, which was associated with an increase in the number of leukocytes in semen, both factors having the potential to favor cell-associated virus transmission. Semen CD4(+) T cells and macrophages were productively infected at all stages of infection and were infectious in vitro. Lymphocytes had a mucosal phenotype and expressed activation (CD69 & HLA-DR) and migration (CCR5, CXCR4, LFA-1) markers. CD69 expression was increased in semen T cells by SIV infection, at all stages of infection. Macrophages predominated at all stages and expressed CD4, CCR5, MAC-1 and LFA-1. Altogether, we demonstrated that semen contains the two major SIV-target cells (CD4+ T cells and macrophages). Both cell types can be productively infected at all stages of SIV infection and are endowed with markers that may facilitate transmission of infection during sexual exposure

Differentiation defects in primary motoneurons from a SMARD1 mouse model that are insensitive to treatment with low dose PEGylated IGF1

Muscle atrophy and diaphragmatic palsy are the clinical characteristics of spinal muscular atrophy with respiratory distress type 1 (SMARD1), and are well represented in the neuromuscular degeneration $(Nmd^{2J})$ mouse, modeling the juvenile form of SMARD1. Both in humans and mice mutations in the IGHMBP2 gene lead to motoneuron degeneration. We could previously demonstrate that treatment with a polyethylene glycol-coupled variant of IGF1 (PEG-IGF1) improves motor functions accompanied by reduced fiber degeneration in the gastrocnemius muscle and the diaphragm, but has no beneficial effect on motoneuron survival. These data raised the question which cell autonomous disease mechanisms contribute to dysfunction and loss of Ighmbp2-deficient motoneurons. An analysis of primary Ighmbp2-deficient motoneurons exhibited differentiation deficits such as reduced spontaneous $Ca^{2+}$ transients and altered axon elongation, which was not compensated by PEG-IGF1. This points to an IGF1 independent mechanism of motoneuron degeneration that deserves treatment approaches in addition to IGF1

Malolactic Fermentation: A Review of Recent Research on Timing of Inoculation and Possible Yeast-Bacteria Combinations

Despite a considerable research effort, the malolactic fermentation (MLF) process remains to be an imperfectly controlled process and at times MLF can be difficult to get started. One possible explanation for this difficulty is that the wine may be lacking essential nutrient factors for the lactic acid bacteria. Another possible argument is that inhibitory substances are accumulated in wine. Sulfur dioxide and alcohol concentrations and pH have been included among the most significant parameter influencing the growth of malolactic bacteria in wine. King and Beelman suggested that the growth of Oenococcus oeni during alcoholic fermentation might be retarded by the production of toxic compounds by yeasts other than ethanol and sulfur dioxide. Moreover, the malolactic fermentability of wines produced from the same must differ according the yeast strain used in alcoholic fermentation. Previous studies have shown the inhibition of malolactic starter cultures by active growing yeasts due to the production of high levels of SO2 during the early stage of alcoholic fermentation and the effect of acetic acid formed by Kloeckera yeasts and some lactobacilli on growth of Saccharomyces. The goal of our recent investigations is to better understand these interactions, to quantify the nutrient demand by yeast and the nutrient requirements of wine lactic acid bacteria, and to determine whether there are other synergistic interactions between S. cerevisiae and O. oeni in wine. A better understanding of these aspects of wine microorganism physiology will allow us to better match combinations of yeast and bacteria starter cultures with grape varieties, and select the timing of yeast and bacteria inoculations

Lactobacillus plantarum, a New Biological Tool to Control Malolactic Fermentation: A Review and an Outlook

Malolactic fermentation (MLF) in wine is an important step in the vinification of most red and some white wines, as stands for the biological conversion of l-malic acid into l-lactic acid and carbon dioxide, resulting in a decrease in wine acidity. MLF not only results in a biological deacidification, it can exert a significant impact on the organoleptic qualities of wine. This paper reviews the biodiversity of lactic acid bacteria (LAB) in wine, their origin, and the limiting conditions encountered in wine, which allow only the most adapted species and strains to survive and induce malolactic fermentation. Of all the species of wine LAB, Oenococcus oeni is probably the best adapted to overcome the harsh environmental wine conditions and therefore represents the majority of commercial MLF starter cultures. Wine pH is most challenging, but, as a result of global warming, Lactobacillus sp. is more often reported to predominate and be responsible for spontaneous malolactic fermentation. Some Lactobacillus plantarum strains can tolerate the high alcohol and SO2 levels normally encountered in wine. This paper shows the potential within this species for the application as a starter culture for induction of MLF in juice or wine. Due to its complex metabolism, a range of compositional changes can be induced, which may positively affect the quality of the final product. An example of a recent isolate has shown most interesting results, not only for its capacity to induce MLF after direct inoculation, but also for its positive contribution to the wine quality. Degrading hexose sugars by the homo-fermentative pathway, which poses no risk of acetic acid production from the sugars, is an interesting alternative to control MLF in high pH wines. Within this species, we can expect more strains with interesting enological properties