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1.
Molecules ; 29(12)2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38930972

RESUMEN

Copper (II), a vital fungicide in organic viticulture, also acts as a wine oxidation catalyst. However, limited data are currently available on the impact that maximum allowed copper (II) ion doses in wine grapes at harvest can have on aged wine quality. This was the focus of the present study. We investigated the copper (II) effects by producing both white and red wines from musts containing three initial metal concentrations according to the limits set for organic farming. In detail, the influence of copper (II) on fermentation evolution, chromatic characteristics, and phenolic compounds was evaluated. Interestingly, the white wine obtained with the highest permitted copper (II) dose initially exceeded the concentration of 1.0 mg/L at fermentation completion. However, after one year of storage, the copper (II) content fell below 0.2 ± 0.01 mg/L. Conversely, red wines showed copper (II) levels below 1.0 mg/L at the end of fermentation, but the initial copper (II) level in musts significantly affected total native anthocyanins, color intensity, hue, and acetaldehyde concentration. After 12-month aging, significant differences were observed in polymeric pigments, thus suggesting a potential long-term effect of copper (II) on red wine color stability.


Asunto(s)
Acetaldehído , Cobre , Fermentación , Fenoles , Vitis , Vino , Vino/análisis , Cobre/análisis , Acetaldehído/análisis , Fenoles/análisis , Fenoles/química , Vitis/química , Color , Antocianinas/análisis , Antocianinas/química
2.
Food Microbiol ; 115: 104342, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37567616

RESUMEN

Foods containing probiotic bacilli spores are becoming more and more popular because of their resistance to acidic pH, low water activity, and, most importantly, heat processes. Even though spores may engage in some functions, such as immunomodulation, the majority of the beneficial characteristics are unique to vegetative cells. As matter of fact, the development of foods fortified with spores ought to even ensure the germination of the spores along the gastrointestinal tract. In this perspective, vegetative cells derived from spore germination were separately counted on a minimal medium because the traditional approach is based on the use of complex media that allows the spores to germinate independently by stimuli arising from processing or digestion. In more detail, three Bacillus spp. cultures with claimed probiotic properties were added to two entirely unrelated foods (pasta and croissants), and tolerance, as well as germination, was monitored before and after exposure to simulated GIT, as well as at the beginning and end of the products shelf life. For the first time, potential probiotic bacilli were included in a frozen ready-to-bake product. Germination appears to be prevented in this instance, and the impact of baking, matrix and cold storage on spores was examined independently. All of the parameters appeared to contribute, although further research is needed due to the unpredictable behavior exhibited by spores during freezing.


Asunto(s)
Bacillus , Probióticos , Esporas Bacterianas , Calor , Tracto Gastrointestinal
3.
Molecules ; 28(21)2023 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-37959842

RESUMEN

Climate change is causing a significant decrease in the total acidity of grapes and related wines. This represents a serious issue for sparkling wine production. Consequently, before the second fermentation, the acidification of base wines is often necessary. However, the impacts of the most important organic acids on the foam properties of sparkling wines are not yet well known. The impacts of the addition of tartaric, malic, citric, and lactic acid on the quality of Falanghina and Bombino sparkling wines were evaluated. Analyses were performed soon after the second fermentation and one year after aging sur lees. The addition of each different organic acid to the two base wines resulted in significant changes in the sparkling wines not only in terms of pH, titratable acidity, and buffering capacity but also in the content of total amino acids and, in some cases, in the height of the foam and its stability over time. For both grape varieties, acidified wines showed a lower content of total amino acids in comparison with the control wines. The addition of lactic acid determined a higher persistency of the foam even after one year of aging sur lees only in Falanghina wines. The results obtained herein highlight the importance of organic acids and the pH of the base wines for the content of amino acids in sparkling wines. No strict correlation between organic acid addition and the foamability of wines was observed.


Asunto(s)
Vitis , Vino , Vino/análisis , Vitis/química , Compuestos Orgánicos , Aminoácidos/análisis , Ácido Láctico
4.
Food Microbiol ; 90: 103482, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32336356

RESUMEN

In this study, 53 Staphylococcus (S.) aureus strains were typed by 16S-23S rDNA intergenic spacer region (ISR) typing and staphylococcal enterotoxin gene (SEg) typing for all the staphylococcal enterotoxin (se) and staphylococcal enterotoxin-like toxin (sel) genes known to date, revealing a higher discriminatory power than that of multi locus sequence typing. Six strains, one of each ISR- and SEg-type, were genome sequenced and the ability to produce some classical and new SEs when growing in milk was investigated. The manual analysis of the six genomes allowed us to confirm, correct and expand the results of common available genomic data pipelines such as VirulenceFinder. Moreover, it enabled us to (i) investigate the actual location of se and sel genes, even for genes such as selY, whose location (in the core genome) was so far unknown, (ii) find novel allelic variants of se and sel genes and pseudogenes, (iii) correctly annotate se and sel genes and pseudogenes, and (iv) discover a novel type of enterotoxin gene cluster (egc), i.e. the egc type 5 in strains 356P and 364P, while S. argenteus MSHR1132 harbored the egc type 6. Four of the six S. aureus strains produced sufficient amounts of SEA, SEC, SED and SEH in milk to cause staphylococcal food poisoning (SFP), with S. aureus 372 P being the highest producer of SED in milk found to date, producing as much as ca. 47,300 ng/mL and 49,200 ng/mL of SED, after 24 and 48 h of incubation in milk at 37 °C, respectively. S. aureus 372 P released a low amount of SER in milk, most likely because the seR gene was present as a pseudogene, putatively encoding only 51 amino acids. These findings confirm that not only the classical SEs, but also the new ones can represent a potential hazard for the consumers' health if produced in foods in sufficient amounts. Therefore, the detection of SEs in foods, especially if involved in SFP cases, should focus not only on classical, but also on all the new SEs and SEls known to date. Where reference methods are unavailable, the presence of the relevant genes, by using the conventional and real time PCR protocols we exhaustively provided herein, and their nucleotide sequences, should be investigated.


Asunto(s)
Enterotoxinas/genética , Genoma Bacteriano , Leche/microbiología , Alimentos Crudos/microbiología , Staphylococcus aureus/clasificación , Staphylococcus aureus/patogenicidad , Animales , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , Microbiología de Alimentos/métodos , Familia de Multigenes , Tipificación de Secuencias Multilocus , Intoxicación Alimentaria Estafilocócica/prevención & control , Staphylococcus aureus/aislamiento & purificación , Secuenciación Completa del Genoma
5.
J Food Sci Technol ; 57(7): 2602-2611, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32549610

RESUMEN

Wines produced from Sangiovese (sg) grapes, the most cultivated red grape variety in Italy and widely grown across the world, is often subjected to loss of clarity due to the formation of a deposit constituted by fine needle-shaped crystals. In this work, a qualitative study by 1H-NMR and 13C-NMR analysis of the deposit obtained by filtering cloudy sg wines showed that it was constituted by crystals of quercetin (Q). The analysis of hydro-alcoholic solutions (12% ethanol and pH 3.2.) and red wines added with increasing amounts of Q showed that, above 3 mgL-1 of Q, a deposit can be detected and, the time necessary for its formation depends on the medium. The comparison among sg and other 11 monovarietal wines showed that sg was the richest in Q and quercetin glycosides (GQ). Both Q and GQ decreased in the analyzed solutions over time and the decrease was faster for Q than for GQ. The controlled exposure to oxygen determined a decrease of Q higher than the 50% of the initial values. Data obtained in this study suggested that practices as micro-oxygenation and wood aging could help to decrease the amount of Q in sg wines.

6.
Compr Rev Food Sci Food Saf ; 18(2): 455-479, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-33336947

RESUMEN

The use of sulfur dioxide (SO2 ) as wine additive is able to ensure both antioxidant protection and microbiological stability. In spite of these undeniable advantages, in the last two decades the presence of SO2 in wine has raised concerns about potential adverse clinical effects in sensitive individuals. The winemaking industry has followed the general trend towards the reduction of SO2 concentrations in food, by expressing at the same time the need for alternative control methods allowing reduction or even elimination of SO2. In the light of this, research has been strongly oriented toward the study of alternatives to the use of SO2 in wine. Most of the studies have focused on methods able to replace the antimicrobial activity of SO2 . This review article gives a comprehensive overview of the current state-of-the-art about the chemical additives and the innovative physical techniques that have been proposed for this purpose. After a focus on the chemistry and properties of SO2 in wine, as well as on wine spoilage and on the conventional methods used for the microbiological stabilization of wine, recent advances on alternative methods proposed to replace the antimicrobial activity of SO2 in winemaking are presented and discussed. Even though many of the alternatives to SO2 showed good efficacy, nowadays no other physical technique or additive can deliver the efficacy and broad spectrum of action as SO2 (both antioxidant and antimicrobial), therefore the alternative methods should be considered a complement to SO2 in low-sulfite winemaking, rather than being seen as its substitutes.

7.
J Sci Food Agric ; 98(6): 2285-2294, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28990658

RESUMEN

BACKGROUND: Five probiotic lactobacilli were tested, alone or in combination with two commercial starters, to select the most suitable strain for a probiotic bovine salami production. Lactobacillus plantarum 299v was used with both starters, to make salami according to a traditional recipe. Salami obtained by using just the starters and by spontaneous fermentation, served as control. Microbial dynamics, as well as the main physico-chemical parameters, were monitored throughout ripening. The survival of probiotic 299v was confirmed by strains' tracking by means of RAPD-PCR coupled to a culture-independent approach PCR-DGGE-based. RESULTS: The results showed a remarkable viability of the probiotic strain even after 60 days of storage. Experimental salami exhibited the same level of sensory acceptance of control salami, were hygienically safe, and characterised by pH, weight loss and microbiological loads within the ranges conventionally advocated for optimal fermented sausages. CONCLUSION: Outcomes indicate the workable possibility of using second-quality beef cuts for probiotic salami production. © 2017 Society of Chemical Industry.


Asunto(s)
Lactobacillus plantarum/metabolismo , Productos de la Carne/microbiología , Probióticos/análisis , Animales , Bovinos , Fermentación , Microbiología de Alimentos , Humanos , Lactobacillus plantarum/genética , Lactobacillus plantarum/aislamiento & purificación , Productos de la Carne/análisis , Gusto
8.
J Sci Food Agric ; 98(9): 3324-3332, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29240238

RESUMEN

BACKGROUND: Since processing technology and storage may influence the sensory and nutritional value as well as the shelf life of pomegranate juice (PJ), mild technologies based on microfiltration may be a promising alternative to heat treatments for fruit juice preservation. In this study, physicochemical and microbiological properties of raw (RPJ), microfiltered (MPJ) and cloudy pasteurized (PPJ) PJ were compared over a period of 4 weeks. RESULTS: Data demonstrated that microfiltration was comparable to pasteurization in guaranteeing microbiological stability of the juice, avoiding spoilage of the final product. After treatment, PPJ showed the highest amounts of gallic acid (GA) and ellagic acid derivatives (EAs). During storage, the amount of ellagitannins, EAs and GA similarly decreased in all types of juice. Trends towards variations of monomeric anthocyanins in MPJ and variations of polymeric and copigmented anthocyanins in both MPJ and PPJ were found over storage. CONCLUSION: The optimization of pretreatments and filtration parameters can lead to the industrial scale-up of microfiltration technology for the development of high-quality non-heat-treated PJ. © 2017 Society of Chemical Industry.


Asunto(s)
Filtración/métodos , Manipulación de Alimentos/métodos , Jugos de Frutas y Vegetales/análisis , Lythraceae , Fenoles/análisis , Compuestos Orgánicos Volátiles/análisis , Antocianinas/análisis , Fenómenos Químicos , Ácido Elágico/análisis , Microbiología de Alimentos , Conservación de Alimentos , Jugos de Frutas y Vegetales/microbiología , Ácido Gálico/análisis , Calor , Taninos Hidrolizables/análisis , Valor Nutritivo , Pasteurización
9.
Appl Environ Microbiol ; 83(17)2017 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-28625991

RESUMEN

Target-gene amplicon sequencing is the most exploited high-throughput sequencing application in microbial ecology. The targets are taxonomically relevant genes, with 16S rRNA being the gold standard for bacteria. As for fungi, the most commonly used target is the internal transcribed spacer (ITS). However, the uneven ITS length among species may promote preferential amplification and sequencing and incorrect estimation of their abundance. Therefore, the use of different targets is desirable. We evaluated the use of three different target amplicons for the characterization of fungal diversity. After an in silico primer evaluation, we compared three amplicons (the ITS1-ITS2 region [ITS1-2], 18S ribosomal small subunit RNA, and the D1/D2 domain of the 26S ribosomal large subunit RNA), using biological samples and a mock community of common fungal species. All three targets allowed for accurate identification of the species present. Nevertheless, high heterogeneity in ITS1-2 length was found, and this caused an overestimation of the abundance of species with a shorter ITS, while both 18S and 26S amplicons allowed for more reliable quantification. We demonstrated that ITS1-2 amplicon sequencing, although widely used, may lead to an incorrect evaluation of fungal communities, and efforts should be made to promote the use of different targets in sequencing-based microbial ecology studies.IMPORTANCE Amplicon-sequencing approaches for fungi may rely on different targets affecting the diversity and abundance of the fungal species. An increasing number of studies will address fungal diversity by high-throughput amplicon sequencing. The description of the communities must be accurate and reliable in order to draw useful insights and to address both ecological and biological questions. By analyzing a mock community and several biological samples, we demonstrate that using different amplicon targets may change the results of fungal microbiota analysis, and we highlight how a careful choice of the target is fundamental for a thorough description of the fungal communities.


Asunto(s)
Hongos/genética , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Técnicas de Tipificación Micológica/métodos , Biodiversidad , Cartilla de ADN/genética , ADN de Hongos/genética , ADN Intergénico/genética , Hongos/clasificación , Hongos/aislamiento & purificación , ARN Ribosómico 18S/genética
10.
Food Microbiol ; 63: 117-122, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28040157

RESUMEN

Spontaneous alcoholic fermentation of grape must is a complex process, carried out by indigenous yeast populations arising from the vineyard or the winery environment and therefore representing an autochthonous microbial terroir of the production area. Microbial diversity at species and biotype level is extremely important in order to develop the composite and typical flavour profile of DOCG (Appellation of Controlled and Guaranteed Origin) wines. In this study, we monitored fungal populations involved in spontaneous fermentations of Aglianico and Greco di Tufo grape must by high-throughput sequencing (HTS) of 18S rRNA gene amplicons. We firstly proposed an alternative/addition to ITS as target gene in HTS studies and highlighted consistency between the culture-dependent and -independent approaches. A complex mycobiota was found at the beginning of the fermentation, mainly characterized by non-Saccharomyces yeasts and several moulds, with differences between the two types of grapes. Moreover, Interdelta patterns revealed a succession of several Saccharomyces cerevisiae biotypes and a high genetic diversity within this species.


Asunto(s)
Fermentación , Genes de ARNr , Variación Genética , Micobioma , ARN Ribosómico 18S/genética , Vino/microbiología , Microbiología de Alimentos , Hongos/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Microbiología Industrial , Micobioma/genética , Técnicas de Tipificación Micológica , Saccharomyces cerevisiae , Vitis/microbiología
11.
J Dairy Sci ; 100(12): 9539-9550, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28987582

RESUMEN

Sweeteners and flavors are generally added to yogurt to make them more palatable. However, the addition of these ingredients may affect the fermentation process of yogurt as well as its physical and sensory characteristics. Consumers prioritize yogurt products that are "natural." A modified single-chain form of the natural sweet protein monellin extracted from the fruit of Dioscoreophyllum cumminsii, called MNEI, could be a useful alternative to artificial sweeteners. The aim of the present work was to evaluate new rapid sensory methods in combination with rheology to assess the viability of using MNEI to develop sweetened yogurts without the calories of sugar. We studied the gelation and cooling kinetics of 4 yogurt samples (unsweetened or sweetened with MNEI, aspartame, or sucrose) by using a rheometer. Furthermore, the 4 yogurts, with and without addition of a flavoring agent, were characterized from a sensory perspective using a combination of 2 rapid sensory methods, ultra flash profile and flash profile. Rheological results showed that, when added at typical usage levels, aspartame, sucrose, and MNEI did not generally affect the yogurt fermentation process or its rheological properties. Sensory results demonstrated that texture attributes of yogurts with aspartame and sucrose were strongly linked to sweetness and flavor perception, but this was not true for MNEI-sweetened yogurts. In contrast to results obtained from samples sweetened with sucrose and aspartame, MNEI protein did not sweeten the yogurt when added before fermentation. This study highlights the enhancing effect of flavor on sweetness perception, supporting previous reports that noted synergistic effects between sucrose or aspartame and flavors. Hence, future studies should be conducted to determine how sweet proteins behave in yogurt when added after fermentation.


Asunto(s)
Aspartame/análisis , Sacarosa/análisis , Edulcorantes/análisis , Gusto , Yogur/análisis , Adulto , Animales , Femenino , Fermentación , Frutas/química , Humanos , Masculino , Reología
12.
BMC Microbiol ; 16: 87, 2016 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-27206734

RESUMEN

BACKGROUND: Manure can provide a favourable environment for pathogens' survival. De-contamination may be conducted by extended storage, until field conditions are suitable for application to land as source of agricultural nutrients. RESULTS: The hygienic evaluation of manure and slurry coming from a plant that collects cattle livestock wastes from a big slaughterhouse was carried out. Samples were even collected from spillages in the area around the plant. Microbial analyses highlighted the massive presence of faecal indicators in all samples: mean counts of Escherichia coli and enterococci were always above EU limits for marketable processed manure products. Cultures referable to the genus Brucella spp. were recorded in two samples of fresh manure but not in the aged ones. Conventional isolation techniques failed to detect members of the Mycobacterium genus, while by means of IS900 and F57 PCR real-time system on DNA directly extracted from environmental samples, the pathogen was detected in all cases. CONCLUSIONS: Thoughtful design of manure storage infrastructure is critical to prevent spills and over-topping of an open structure. The documented overload situation seems to lay the basis for an ongoing environmental contamination by enteric organisms and opportunistic pathogens circuit faecal-oral route. Moreover, the type of wastes analysed during this study, namely a mixture of fresh cattle manure, bedding and rumen content, needs a longer storage period or, alternatively, of specific chemical, biological or thermal treatments for stabilization.


Asunto(s)
Bacterias/clasificación , Bacterias/aislamiento & purificación , Estiércol/microbiología , Mataderos , Animales , Bovinos , Humanos , Eliminación de Residuos/métodos , Microbiología del Suelo , Zoonosis/microbiología
13.
Food Microbiol ; 53(Pt B): 128-34, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26678140

RESUMEN

Nine Saccharomyces cerevisiae cultures, isolated from different sources, were tested for their ability to reduce tannins reactive towards salivary proteins, and potentially responsible for wine astringency. Strains were preliminary genetically characterized and evaluated for physiological features of technological interest. Laboratory-scale fermentations were performed in three synthetic media: CT) containing enological grape tannin; CTP) CT supplemented with organic nitrogen sources; CTPV) CTP supplemented with vitamins. Adsorption of total tannins, tannins reactive towards salivary proteins, yellow pigments, phenolics having antioxidant activity, and total phenols, characterizing the enological tannin, was determined by spectrophotometric methods after fermentation. The presence of vitamins and peptones in musts greatly influenced the adsorption of tannins reactive towards salivary proteins (4.24 g/L gallic acid equivalent), thus promoting the reduction of the potential astringency of model wines. With reference to the different phenolic classes, yeast strains showed different adsorption abilities. From a technological point of view, the yeast choice proved to be crucial in determining changes in gustative and mouthfeel profile of red wines and may assist winemakers to modulate colour and astringency of wine.


Asunto(s)
Taninos/química , Vino/microbiología , Levaduras/metabolismo , Color , Fermentación , Humanos , Fenoles/metabolismo , Taninos/metabolismo , Gusto , Vitis/química , Vitis/microbiología , Vino/análisis , Levaduras/clasificación , Levaduras/genética , Levaduras/aislamiento & purificación
14.
World J Microbiol Biotechnol ; 32(1): 13, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26712628

RESUMEN

Spray-drying (SD) is widely considered a suitable method to preserve microorganisms, but data regarding yeasts are still scanty. In this study, the effect of growing media, process variables and carriers over viability of a wild wine Saccharomyces (S.) cerevisiae LM52 was evaluated. For biomass production, the strain was grown (batch and fed-batch fermentation) in a synthetic, as well as in a beet sugar molasses based-medium. Drying of cells resuspended in several combinations of soluble starch and maltose was performed at different inlet and outlet temperatures. Under the best conditions-suspension in soluble starch plus maltose couplet to inlet and outlet temperatures of 110 and 55 °C, respectively-the loss of viability of S. cerevisiae LM52 was 0.8 ± 0.1 and 0.5 ± 0.2 Log c.f.u. g(-1) for synthetic and molasses-based medium, respectively. Similar results were obtained when S. cerevisiae strains Zymoflore F15 and EC1118, isolated from commercial active dry yeast (ADY), were tested. Moreover, powders retained a high vitality and showed good fermentation performances up to 6 month of storage, at both 4 and -20 °C. Finally, fermentation performances of different kinds of dried formulates (SD and ADY) compared with fresh cultures did not show significant differences. The procedure proposed allowed a small-scale production of yeast in continuous operation with relatively simple equipment, and may thus represent a rapid response-on-demand for the production of autochthonous yeasts for local wine-making.


Asunto(s)
Desecación/métodos , Viabilidad Microbiana , Saccharomyces cerevisiae/crecimiento & desarrollo , Vino/microbiología , Técnicas de Cultivo Celular por Lotes , Biomasa , Recuento de Colonia Microbiana/métodos , Medios de Cultivo , Fermentación , Microbiología de Alimentos , Calor , Concentración de Iones de Hidrógeno , Melaza , Preservación Biológica
15.
Int J Food Sci Nutr ; 66(3): 254-9, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25657101

RESUMEN

The ability of probiotic bacteria (Lactobacillus acidophilus La5 and Bifidobacterium animalis Bb12), to produce conjugated linoleic acid (CLA) in association with Streptococcus thermophilus and Lb. bulgaricus during milk fermentation has been evaluated in this study. Pasteurized cow milk and infant formula were used. Infant formula was selected for its high linoleic acid content, for being a source of CLA and for its prebiotic compounds, e.g. galacto-oligosaccharides. The microorganisms were not able to increase the CLA content of the fermented products under the given experimental conditions. No statistically significant differences (p > 0.05) occurred between the CLA content in milk and the fermented samples. The CLA contents of 10 commercial fermented milk products were determined. The highest CLA content was observed in fermented milk containing only Str. thermophilus and Lb. bulgaricus.


Asunto(s)
Bacterias , Productos Lácteos Cultivados/química , Fermentación , Ácidos Linoleicos Conjugados/metabolismo , Prebióticos , Probióticos , Animales , Bifidobacterium , Ácidos Grasos/metabolismo , Humanos , Fórmulas Infantiles/metabolismo , Lactobacillus , Leche/metabolismo , Oligosacáridos/metabolismo , Streptococcus
16.
Food Microbiol ; 42: 47-55, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24929716

RESUMEN

Chestnuts are very perishable fruits, whose quality may be compromised during postharvest handling. Damage can be caused both by insects and fungi. Water curing, a commonly used postharvest method, is based on soaking fruits in water typically for about one week. Factors that affect effectiveness of water curing have only been explained partially. A decrease in pH, likely imputable to a light fermentation caused by lactic acid bacteria, may inhibit the growth of moulds. In this study a Lactobacillus pentosus strain was selected for its ability to inhibit fungi, and used as a starter culture during water curing. As second goal, a reduction of the environmental impact of the process was evaluated by using water that had been re-cycled from a previous curing treatment. Experiments were performed on pilot as well as on farm scale. In all trials, microbial dynamics were evaluated by means of a polyphasic approach including conventional and molecular-based analyses. According to results, the employment of an adjunct culture appears as a very promising opportunity. Even if no reduction in the duration of the process was achieved, waters exhibited a minor microbial complexity and fruits did not lose the natural lustre after the process.


Asunto(s)
Fagaceae/microbiología , Conservación de Alimentos/métodos , Agua/química , Antibiosis , Biodiversidad , Fagaceae/química , Contaminación de Alimentos/análisis , Contaminación de Alimentos/prevención & control , Conservación de Alimentos/instrumentación , Frutas/química , Frutas/microbiología , Hongos/clasificación , Hongos/genética , Hongos/aislamiento & purificación , Hongos/fisiología , Concentración de Iones de Hidrógeno , Lactobacillus/fisiología
17.
Foods ; 13(4)2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38397610

RESUMEN

Ripened sheep sausages are widely consumed in Italy, particularly in Sardinia. Despite their driving role in flavor and color development, coagulase-negative staphylococci in these products have been rarely investigated. A total of 70 CoNS cultures isolated from Sardinian sheep sausages were characterized by rep-PCR and M13-RAPD typing and identified by 16S rDNA sequencing. S. xylosus and S. equorum accounted for more than 70% of the total isolates, whilst S. pasteuri (8.5%), S. succinus (2.8%), and S. haemolyticus (2.8%) were less represented. The genes encoding the synthesis of putrescine, tyramine, cadaverine, and histamine were evaluated by PCR. None of the strains hosted genes for decarboxylases, except one S. pasteuri strain that was potentially a tyramine-producer. Antibiotic resistance was evaluated, along with nitrate reductase, lipolytic, and proteolytic activity, in a pool of selected cultures. Resistance to the primary antibiotics was rather widespread. S. xylosus, S. equorum, and S. pasteuri strains were all resistant to amoxicillin and kanamycin. S. equorum strains were sensitive to all tested antibiotics. S. xylosus strains were all resistant to penicillin B. Conversely, all S. pasteuri strains were resistant to both ampicillin and penicillin B, and four out of five strains exhibited tetracycline resistance. The high variability in the production of sheep sausages makes the search for adjunct cultures of crucial relevance. According to this perspective, the characterization of the autochthonous CSN population represents the first step to approach a starter selection.

18.
Food Microbiol ; 36(2): 161-9, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24010594

RESUMEN

The main challenge to probiotics, during their passage through the gastrointestinal tract, are the acidic gastric secretions of the stomach, and the bile salts released into the duodenum. The survival of the strains, in this phase, is strongly influenced by the food used for their delivery. This work is part of a project studying the development of novel food processes, based on the use of chestnuts from cultivar "Castagna di Montella". In detail, the effect of indigestible chestnut fiber and of chestnut extract on the viability of selected lactic acid bacteria strains was evaluated. Among 28 cultures, twelve strains were selected, on the basis of tolerance to low pH values and bile salts, and submitted to exposition to simulated gastric or bile juice in presence of chestnut extract with or without immobilization in chestnut fiber. The presence of chestnut extract proved to play a significant role on the gastric tolerance improvement of lactobacilli. The recorded protective effect could not be simply related to the starch or reducing sugars content. RP-HPLC demonstrated that in the chestnut flour, there are one or more hydrophobic peptides or oligopeptides, which specifically offer a marked resistance to simulated gastric juice, albeit present at low concentration. These beneficial effects proved to be dependent by the cultivar used to produce the flour.


Asunto(s)
Fibras de la Dieta/farmacología , Fagaceae/química , Tracto Gastrointestinal/microbiología , Lactobacillus/crecimiento & desarrollo , Extractos Vegetales/farmacología , Ácidos y Sales Biliares/farmacología , Fibras de la Dieta/metabolismo , Digestión , Fagaceae/metabolismo , Tracto Gastrointestinal/metabolismo , Humanos , Lactobacillus/efectos de los fármacos , Lactobacillus/metabolismo , Viabilidad Microbiana , Modelos Biológicos , Nueces/química , Nueces/metabolismo , Extractos Vegetales/metabolismo , Prebióticos/análisis , Probióticos/metabolismo
19.
Foods ; 12(3)2023 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-36766056

RESUMEN

A fermentation of Fiano di Avellino grape must was carried out at 9°C with the aim of selecting cryotolerant yeast strains and testing their fermentative performances and volatile production following molecular characterization. A total of 20 yeast cultures were isolated at different fermentation stages. Based on molecular identification and characterization, Metschnikowia (M.) pulcherrima, Hanseniaspora (H.) uvarum, Staremerella (St.) bacillaris, Saccharomyces (S.) cerevisiae, S. kudriavzevii, and S. paradoxus were found to be the yeast species dominating the fermentation. S. paradoxus has been rarely isolated in vineyards and never in the cellar environment. Moreover, in this study, S. kudriavzevii is detected for the first time in vine-wine environments. Both S. kudriavzevii and S. paradoxus co-occurred with S. cerevisiae when grapes were micro-fermented at low temperatures. The growth kinetics of the three species were greatly affected by the fermentation temperature. As a consequence, Fiano wines obtained with S. kudriavzevii and S. paradoxus significantly differed from those made by S. cerevisiae in terms of chemical and volatile composition.

20.
Front Plant Sci ; 14: 1201287, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37771498

RESUMEN

Sexual reproduction has contributed to a significant degree of variability in cultivated grapevine populations. However, the additional influence of spontaneous somatic mutations has played a pivotal role in shaping the diverse landscape of grapevine agrobiodiversity. These naturally occurring selections, termed 'clones,' represent a vast reservoir of potentially valuable traits and alleles that hold promise for enhancing grape quality and bolstering plant resilience against environmental and biotic challenges. Despite their potential, many of these clones remain largely untapped.In light of this context, this study aims to delve into the population structure, genetic diversity, and distinctive genetic loci within a collection of 138 clones derived from six Campanian and Apulian grapevine varieties, known for their desirable attributes in viticulture and winemaking. Employing two reduced representation sequencing methods, we extracted Single-Nucleotide Polymorphism (SNP) markers. Population structure analysis and fixation index (FST) calculations were conducted both between populations and at individual loci. Notably, varieties originating from the same geographical region exhibited pronounced genetic similarity.The resulting SNP dataset facilitated the identification of approximately two hundred loci featuring divergent markers (FST ≥ 0.80) within annotated exons. Several of these loci exhibited associations with essential traits like phenotypic adaptability and environmental responsiveness, offering compelling opportunities for grapevine breeding initiatives. By shedding light on the genetic variability inherent in these treasured traditional grapevines, our study contributes to the broader understanding of their potential. Importantly, it underscores the urgency of preserving and characterizing these valuable genetic resources to safeguard their intra-varietal diversity and foster future advancements in grapevine cultivation.

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