Rapid screening method to assess tannin antioxidant activity in food-grade botanical extract

Fourier transform infrared (FTIR) spectroscopy measurements were used for the prediction of commercial tannins antioxidant capacity, i.e. DPPH, through Partial-least squares (PLS) regression. Plot of the leave-one-out full cross-validated PLS predicted scavenging activity values (DPPH %) with a good correlation (r= 0.82), proving FTIR succeeded to rapidly provide information on commercial tannins antioxidant capacit

Preliminary Study of the Effects of Pulsed Electric Field (PEF) Treatments in Wines Obtained from Early-Harvested Sangiovese Grapes.

In this experiment, the effect of pulsed electric field (PEF) technology on the extractability of anthocyanins and polyphenols in early-harvested Sangiovese red grapes (16.9\ub0Bx sugar, 3.26 pH, and 10.4 g/L titratable acidity) from Emilia Romagna (Italy) was investigated. Electric field strengths were in the range of 0.9\u20133 kV/cm, generated by the application of short, high-voltage pulses, and the grapes were subjected to specific energies from 10.4 to 32.5 kJ/kg immediately after crushing and destemming to produce a pre-fermentative pulsed electric field treatment on a pilot scale. Grape musts and wines were analyzed for color components and polyphenols content from pressing of juices up to 3 months from the end of the fermentation of wines. Furthermore, the freshly-fermented wines were subjected to accelerated aging conditions (i.e., warming under 40\ub0C for 32 days) to simulate the evolution of color parameters with time. The color intensity was generally higher in treated musts and wines compared to the control, further increased by raising the intensity of the electric field. Results suggested the potentialities of pulsed electric fields (PEFs) as a mild pre-fermentative process to assist maceration and to increase the polyphenolic content of musts obtained by early-harvested Sangiovese grapes

The macromolecular diversity of Italian monovarietal red wines

13openInternationalItalian coauthor/editorWhile red wine phenolics have been extensively studied, polysaccharides and proteins have not received the same level of attention, especially when considering Italian wines. In this study, for the first time, quantitative and qualitative data on the macromolecular (proteins and polysaccharides) and tannin composition of 110 monovarietal red wines from 11 of the most important Italian grape varieties are reported. The winemaking did not include any filtration, oak contact, fining treatments, or ageing on yeast lees. Results highlighted a great inter- and intra- varietal diversity. The protein content ranged between 0 and 159 mg/L, polysaccharides between 211 and 1081 mg/L and total tannins between 171 and 3746 mg/L, with averages of 41 mg/L, 497 mg/L and 1687 mg/L, respectively. Six varieties with protein content representative of the variability observed were selected and submitted to electrophoresis. Within each variety, the SDS-PAGE mobility of protein-tannin complexes was similar but showed two distinct patterns for wines of different varieties (higher mobility for Corvina, Teroldego and Raboso Piave, lower mobility for Nebbiolo, Aglianico, Cannonau), suggesting that the Italian monovarietal wines can be diverse also in their colloidal-forming structures. This can be explained by looking at the different percentages of protein-reactive tannins (TBSA) on the total tannin content (TMCP), which is a varietal characteristicopenMarangon, Matteo; De Iseppi, Alberto; Gerbi, Vincenzo; Mattivi, Fulvio; Moio, Luigi; Piombino, Paola; Parpinello, Giuseppina Paola; Rolle, Luca; Slaghenaufi, Davide; Versari, Andrea; Vrhovsek, Urska; Ugliano, Maurizio; Curioni, AndreaMarangon, M.; De Iseppi, A.; Gerbi, V.; Mattivi, F.; Moio, L.; Piombino, P.; Parpinello, G.P.; Rolle, L.; Slaghenaufi, D.; Versari, A.; Vrhovsek, U.; Ugliano, M.; Curioni, A

Multivariate prediction of Saliva Precipitation Index for relating selected chemical parameters of red wines to the sensory perception of astringency

Astringency is an essential sensory attribute of red wine closely related to the saliva precipitation upon contact with the wine. In this study a data matrix of 52 physico-chemical parameters was used to predict the Saliva Precipitation Index (SPI) in 110 Italian mono-varietal red wines using partial least squares regression (PLSr) with variable selection by Variable Importance for Projection (VIP) and the significance of regression coefficients. The final PLSr model, evaluated using a test data set, had 3 components and yielded an R2test of 0.630 and an RMSEtest of 0.994, with 19 independent variables whose regression coefficients were all significant at p < 0.05. Variables selected in the final model according to the decreasing magnitude of their absolute regression coefficient include the following: Procyanidin B1, Epicatechin terminal unit, Total aldehydes, Protein content, Vanillin assay, 520 nm, Polysaccharide content, Epigallocatechin PHL, Tartaric acid, Volatile acidity, Titratable acidity, Catechin terminal unit, Proanthocyanidin assay, pH, Tannin-Fe/Anthocyanin, Buffer capacity, Epigallocatechin PHL gallate, Catechin + epicatechin PHL, and Tannin-Fe. These results can be used to better understand the physico-chemical relationship underlying astringency in red win