Search results for "Volatile Organic Compound"

Multi-omics of Pseudoalteromonas haloplanktis TAC125: a quest for antimicrobial metabolic pathways

Backgrounds The Antarctic strain Pseudoalteromonas haloplanktis TAC125 is one of the model organisms of cold-adapted bacteria and is currently exploited as a new alternative expression host for numerous biotechnological applications. Interestingly, this bacterium has been reported to be able to inhibit the growth of Burkholderia cepacia complex (Bcc) strains, opportunistic pathogens responsible for the infection of immune-compromised patients. Most likely, this occurs through the synthesis of several different compounds, including Volatile Organic Compounds (VOCs), whose nature and characteristics are currently mostly unknown. Objectives To obtain a complete picture of cellular processes di…

Volatile organic compounds in truffle (Tuber magnatum Pico): Comparison of samples from different regions of Italy and from different seasons

2015

AbstractIn this paper volatile organic compounds (VOCs) from Tuber magnatum fruiting bodies were analyzed using a PTR-TOF-MS instrument. The aim was to characterize the VOC's profile of the fruiting bodies and identify if any VOCs were specific to a season and geographical areas. Multiple factorial analysis (MFA) was carried out on the signals obtained by MS. Experiments using ITS region sequencing proved that the T. magnatum life cycle includes the formation of fruiting bodies at two different times of the year. The VOCs profiles diverge when different seasonal and geographical productions are considered. Using PTR-TOF-MS, compounds present at levels as low pptv were detected. This made it…

Impact of a minimally processing route for the production of infant formulas on the organoleptic properties

2022

Many new-borns are fed with substitutes of breast milk. These products undergo several heat treatments, necessary to insure their microbiologic safety but probably modifying their organo-leptic properties. High temperature can damage milk proteins and form Maillard reaction prod-ucts with lactose. Microfiltration – to replace the heat treatments for a milk debacterization – combined with a soft spray-drying is currently an alternative little exploited to produce infant formulas (IFs) although microbiologically safe. The aim of this study was to determine the im-pact of such processing route on the organoleptic properties of the IFs. Three experimental IFs were manufactured at a semi-industr…

Persistence of a mixed lactic acid bacterial starter culture during lysine fortification of sourdough breads by addition of pistachio powder

2020

Abstract Pistachio powder was added to flour or semolina to evaluate its contribution to increase the amount of lysine in bread. Bread production was carried out by sourdough technology using a selected 3-species (Lactobacillus sanfranciscensis/Leuconostoc citreum/Weissella cibaria) lactic acid bacterial (LAB) starter culture. All sourdoughs were subjected to a long-time fermentation (21 h) and showed levels of LAB around 109 CFU/g, indicating the suitability of pistachio powder for lactic fermentation. Yeasts were also detected, in particular in semolina trials. MiSeq Illumina technology was applied to investigate the bacterial composition of sourdoughs evidencing a different distribution …

Diversity and technological potential of lactic acid bacteria of wheat flours

2013

Abstract Lactic acid bacteria (LAB) were analysed from wheat flours used in traditional bread making throughout Sicily (southern Italy). Plate counts, carried out in three different media commonly used to detect food and sourdough LAB, revealed a maximal LAB concentration of approximately 4.75 Log CFU g−1. Colonies representing various morphological appearances were isolated and differentiated based on phenotypic characteristics and genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR. Fifty unique strains were identified. Analysis by 16S rRNA gene sequencing grouped the strains into 11 LAB species, which belonged to six genera: Enterococcus, Lactobacillus, Lactococcus, Leucono…

Effects of different yeast strains, nutrients and glutathione-rich inactivated yeast addition on the aroma characteristics of Catarratto wines

2021

Catarratto is one of the most common non-aromatic white grape varieties cultivated in Sicily (Southern Italy). In order to improve the aromatic expression of Catarratto wines a trial was undertaken to investigate the effect of yeast strain, nutrition and reduced glutathione. Variables included two Saccharomyces cerevisiae strains, an oenological strain (GR1) and one isolated from honey by-products (SPF52), three different nutrition regimes (Stimula Sauvignon Blanc™ (SS), Stimula Chardonnay™ (SC) and classic nutrition practice), and a specific inactivated yeast rich in reduced glutathione to prevent oxidative processes [Glutastar™ (GIY)] ensuing in ten treatments (T1-T10). Microbiological an…

Amino acids and volatile compounds in wines from Cabernet Sauvignon and Tempranillo varieties subjected to malolactic fermentation in barrels

2012

The aim of the present paper is to compare the behaviour of industrial lactic bacteria and indigenous bacteria of the cellar when malolactic fermentation was carried out in barrels. The effects of these bacteria on the concentration of metabolised amino acids during malolactic fermentation and on the composition of volatile compounds both before and after malolactic fermentation are studied. The experiment was performed with wines of the Tempranillo and Cabernet Sauvignon varieties. An analysis has been made of the easily extractable volatile compounds of the wood and the compounds from the grapes, and the action of the yeasts during the alcoholic fermentation. Acetoin and diacetyl decreas…

Analytical comparison and sensory representativity of SAFE, SPME, and Purge and Trap extracts of volatile compounds from pea flour

2012

Pisum sativum is of great economic and nutritional interest due to its protein content. Nevertheless, pea products are underused as a protein source in human food because of their strong beany flavour. Therefore, the objective of this study was to select an efficient and representative method to extract volatile molecules of pea flour. In the first step, three extraction methods were chosen: solid phase micro extraction (SPME); Purge and Trap extraction and solvent assisted flavour evaporation (SAFE). The corresponding extracts were analysed by gas chromatography coupled with mass spectrometry. In the second step, the sensory representativity of the extracts was assessed either by direct ga…

Dry vs soaked wood: Modulating the volatile extractible fraction of oak wood by heat treatments

2012

The aim of this study was to analyze the impact of the water content of wood on the concentrations of volatile compounds which can be extracted after heat treatments. Head Space-Solid Phase Micro Extraction Gas Chromatography coupled to Mass Spectrometry (HS-SPME GC-MS) has been used to compare the concentrations of six aroma compounds (vanillin, furfural, eugenol, guaiacol and cis- and trans-whisky lactones) in hydroalcoholic extracts of heated oak wood samples either previously soaked in hot water or not. Except for eugenol, concentrations of extracted aromas appeared to be lower in soaked woods than in dry woods for temperatures up to 200 °C. If a delaying effect of water could explain s…

Diversité génétique et aromatique de la truffe de Bourgogne

2013

Truffles are ectomycorrhizal Ascomycota fungi belonging to the Tuberaceae family and more specifically to the Tuber genus. More than thirty Tuber species are currently described in Europe. In this thesis, we specifically focused on the Tuber aestivum-uncinatum model. This truffle is commonly called "Burgundy Truffle" and has a gastronomic and cultural interest.The first part of this thesis focused on the taxonomic status of the Burgundy truffle (Tuber uncinatum). For this, we used a multi-marker approach combining several genetic markers commonly used at the interspecific scale. Our analyses showed that the two taxa, Tuber aestivum (summer truffle) and Tuber uncinatum are conspecific.In the…