Browsing by Author "Tchouakeu Betnga PF"

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    Effects of Long-Term Bottle Storage on Red and Rosé Wines Sealed with Different Types of Closures
    (MDPI (Basel, Switzerland), 2021-12) Tchouakeu Betnga PF; Longo E; Merkytė V; Dupas de Matos A; Rossetti F; Boselli E; Câmara JS; Teixeira JAC; Perestrelo RM
    Volatile and non-volatile chemical profiles, free and total SO2 and dissolved oxygen content were studied in three red (Merlot, Lagrein red, St. Magdalener) and one rosé (Lagrein rosé) wine after 30 months of storage in bottles. Each wine was sealed with closures made of a 'blend' (B) of natural cork microgranules and polymers without glue and was compared with wines closed with other types of corks (C; a technical cork 1 + 1, or an agglomerated natural cork or a natural one-piece cork). Glutathionyl caftaric acid (GRP) was inversely correlated with total SO2 content and was higher in all three red wines closed with B compared to C, whereas epicatechin was higher in three wines closed with C compared to B. Three volatile compounds formed by fermentation (ethyl butanoate, isoamyl lactate, and octanol) were inversely correlated with both free and total SO2. In terms of their volatile profiles, ethyl octanoate and 2,3-butanediol were significantly higher in the Lagrein red wines closed with C closures, whereas no significant difference was observed in Merlot, Lagrein rosé and St. Magdalener wines. Small differences in some phenolic compounds due to the type of closure were found: GRP, syringic acid, (+)-catechin, and (-)-epicatechin differentiated the Merlot wines closed with B from the C closures. Protocatechuic acid and GRP levels differentiated the Lagrein red wines according to their closure type, whereas only (-)-epicatechin differentiated the Lagrein rosé wines. GRP, caffeic acid, (-)-epicatechin, and anthocyanin content differentiated the St. Magdalener wines according to their closure type. Even though St. Magdalener and Lagrein rosé closed with C could be distinguished from those closed with B by using the (sensory) triangle test (α = 0.05), these differences appeared to be relative as it did not include all the wines in a systematic manner.
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    Effects of transport conditions on the stability and sensory quality of wines
    (International Viticulture and Enology Society - IVES, 30/04/2021) Tchouakeu Betnga PF; Longo E; Poggesi S; Boselli E
    The quality of wine can be affected by several factors after bottling: temperature changes, shipment time, type and amount of mechanical stress (vibrations) and environmental conditions, such as light exposure and relative humidity. The effects of delivery using different packaging systems (boxes, bottles, containers) and the impacts of mode of shipment (car, truck, airplane and cargo ship) are reviewed, along with compositional markers, the reactions leading to off-odours and/or off-flavours and the approaches to monitoring transportation conditions (temperature, relative humidity and type and entity of vibration) and their impacts on the sensory profile of the wine. Temperature fluctuations are more prevalent during the transport of wine over land than by sea, and may lead to a decrease in the fresh, fruity and floral aromas of the wine and to premature aging due to the ‘pump’ effect (repeated expansion and contraction cycles). Trans-shipment phases should be reduced to a minimum, especially in hot climates. Vibrations, even for a short period of time (15 days), can alter the overall quality of the product.
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    Terroir Dynamics: Impact of Vineyard and Canopy Treatment with Chitosan on Anthocyanins, Phenolics, and Volatile and Sensory Profiles of Pinot Noir Wines from South Tyrol
    (MDPI (Basel, Switzerland), 2024-04-23) Tchouakeu Betnga PF; Poggesi S; Darnal A; Longo E; Rudari E; Boselli E; Rolle L
    The effects of canopy treatment with chitosan and the effects of the vineyard location on the quality parameters, volatile and non-volatile profiles, and sensory profile of Pinot Noir wines from South Tyrol (Italy) were studied. Multivariate statistical analysis was applied to identify the most relevant compounds associated with the variability in phenolics and anthocyanins (analyzed by UHPLC-MS), volatile components (HS-SPME-GCxGC-ToF/MS), and basic enological parameters. A clear separation of low-altitude wines (350 m.a.s.l.), which had a high concentration of most of the identified volatile compounds, compared to high-altitude wines (800 and 1050-1150 m.a.s.l.) was pointed out. Low altitude minimized the concentration of the most significant anthocyanins in wines from a valley bottom, presumably due to reduced sun exposure. Wines obtained from chitosan-treated canopies, and, more particularly, those subjected to multiple treatments per year showed a higher amount of the main non-volatile phenolics and were sensorially described as having "unpleasant flavors" and "odors", which might suggest that grape metabolism is slightly altered compared to untreated grapevines. Thus, optimization of the treatment with chitosan should be further investigated.