Plant proteins have been proposed as an alternative to animal-origin proteins in the wine industry because they are allergen-free and vegan-friendly. The aim of this study was to evaluate the ...effectiveness of plant proteins as fining agents on red wines with different phenolic composition. Two formulations for commercially available vegetal proteins (potato and pea origin) were assessed at two doses to modulate the fining treatment to the wine phenolic profile. The results evidenced that fining agents derived from plants have different levels of effectiveness on the removal of phenolic compounds depending on the origin, the formulation used, dose applied, and also wine characteristics. On Nebbiolo wine, the study was particularly significant due to its phenolic composition. One pea-based fining agent had an effect comparable to gelatin (animal origin) on the removal of polymeric flavanols with a minor loss of anthocyanins and therefore better preserving the wine color in terms of intensity and hue. For Primitivo, Montepulciano, and Syrah wines, even though there was a formulation-dependent effect, vegetal proteins gave more balanced reductions in terms of target phenolic compounds contributing to astringency and color perception.
Ozone, a powerful oxidative stressor, has been recently used in wine industry as sanitizing agent to reduce spoilage microflora on grapes. In this study, we evaluated ozone-induced metabolic and ...molecular responses during postharvest grape dehydration. Ozone increased the contents of total volatile organic compounds (VOCs), which have a great impact on the organoleptic properties of grapes and wines. Among terpenes, responsible for floral and fruity aroma, linalool, geraniol and nerol were the major aromatic markers of Moscato bianco grapes. They were significantly affected by the long-term ozone treatment, increasing their concentration in the last phases of dehydration (>20% weight loss). At molecular level, our results demonstrated that both postharvest dehydration and ozone exposure induce the biosynthesis of monoterpenes via methylerythritol phosphate (MEP) pathway and of aldehydes from lipoxygenase-hydroperoxide lyase (LOX-HPL) pathway. Therefore, transcriptional changes occurred and promoted the over-production of many important volatile compounds for the quality of white grapes.
Texture analysis is a well-established analytical technique in the food industry for evaluating the mechanical and physical characteristics of both raw ingredients and finished products. Instrumental ...mechanical properties of table grapes, acquired using universal testing machines equipped with specific probes, may be of interest in the viticulture and postharvest sectors to recognize the potential of each variety and help satisfy market requirements. The measured parameters are related to some sensory properties and, therefore, indirectly to consumer acceptability of the product. As texture analysis is a rapid and low-cost analytical technique, it can also be favorably applied in enology as a routine tool for monitoring winegrape quality. Among the different mechanical parameters measurable, berry skin thickness and hardness are indices that reflect anthocyanin extractability and dehydration kinetics with adequate reliability. This review collects the most recent research results from grape texture studies, emphasizes the potentiality and limits of this analytical technique when applied to grape studies, and highlights trends that require further understanding.
Sugars (lactose, glucose, and galactose), nonvolatile acids (citric, orotic, piruvic, lactic, ossalic, and hippuric), some free fatty acids (formic, acetic, propionic, butyric, isobutyric, valeric, ...and isovaleric), diacetyl, and acetoin were separated on an Aminex HPX-87H column using a simple isocratic HPLC method and identified by retention times with ultraviolet and refractive index detectors. With the proposed technique it is possible to evaluate the development of microbial fermentations and, at the same time, degree of cheese ripening. Keywords: Cheese; organic acids; sugars; diacetyl; acetoin; HPLC
The aim of this work was to compare different texture test conditions for the evaluation of instrumental mechanical and acoustic properties of raw and roasted hazelnut (Corylus avellana L.) kernels ...cv. Tonda Gentile Trilobata (TGT). A comparison of compression and shear tests, test speed (0.2, 1.0, 10.0 mm/s), and analyzed axis (x, y, z) combinations was performed. Joint mechanical and acoustic emission acquisitions were used for the first time on hazelnut kernels. The compression test method using 1.0 mm/s speed and analyzed on the x-axis showed the lowest variability of the results. These conditions were then used to evaluate raw kernels during 12 months of storage, conducted in-shell (at ambient temperature) and shelled (refrigerated, vacuum, frozen, with nitrogen modified atmosphere). The main differences among storage conditions were evidenced in rupture force, rupture slope and acoustic maximum peak parameters.
•Instrumental mechanical and acoustic properties were determined on hazelnut kernels.•Compression and shear tests, speed, analyzed axis and roasting effect were compared.•X-axis compression at 1.0 mm/s condition showed the lowest variability.•In-shell stored hazelnuts presented kernel mechanical modifications after 12 months.•Shear test discussed for possible sensory-imitative mechanical and acoustic studies.
This work aimed at investigating red wine olfactory–oral cross-modal interactions, and at testing their impact on the correlations between sensory and chemical variables. Seventy-four Italian red ...whole wines (WWs) from 10 varieties, and corresponding deodorized wines (DWs), were evaluated by sensory descriptive assessment. Total phenols, proanthocyanidins, ethanol, reducing sugars, pH, titratable and volatile acidity were determined. PCA results highlighted different sensory features of the 10 wine types. ANOVAs (p < 0.05) showed that olfactory cues might play modulation effects on the perception of in-mouth sensations with 7 (harsh, unripe, dynamic, complex, surface smoothness, sweet, and bitter) out of 10 oral descriptors significantly affected by odours. Three weak but significant positive correlations (Pearson, p < 0.0001) were statistically found and supported in a cognitive dimension: spicy and complex; dehydrated fruits and drying; vegetal and unripe. In the absence of volatiles, correlation coefficients between sensory and chemical parameters mostly increased. Proanthocyanidins correlated well with drying and dynamic astringency, showing highest coefficients (r > 0.7) in absence of olfactory–oral interactions. Unripe astringency did not correlate with polyphenols supporting the idea that this sub-quality is a multisensory feeling greatly impacted by odorants. Results support the significance of cross-modal interactions during red wine tasting, confirming previous findings and adding new insights on astringency sub-qualities and their predictive parameters.
In vineyards, in-field grape variability attributable to environmental factors can induce differences in the ripening process and, therefore, in the physicochemical characteristics of grape berries. ...This variability is often higher among different growing locations. Automatic, densimetric berry-sorting machines have recently been developed and proposed for use in wineries to reduce this variability, thereby making grapes uniform in terms of density. Densimetric sorting requires the selection of a density value according to objective quality parameters of the berries. The aim of this work was to determine the relationships among different objective quality parameters of Nebbiolo grapes harvested on the same date, such as mechanical properties, phenolic composition, and extractability indices; to determine the berry density estimated by flotation in different salt solutions of densities ranging from 1069 to 1125 kg m−3; and to investigate the influence of the growing location on these relationships. The results revealed that the most promising physicochemical parameters for determining the appropriate density are the total anthocyanin and flavonoid concentrations in the skins, the total flavonoid and oligomer proanthocyanidin contents in the seeds, and skin hardness and thickness. Nevertheless, density selection must be performed for each individual vineyard or homogeneous group of vineyards belonging to the same production zone because the correlation of berry density with these parameters also depends on the vineyard effect. Densimetric sorting of berries can be used to separate grapes with different quality parameters.
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