Comparison of Chromatic and Spectrophotometric Properties of White and Red Wines Produced in Galicia (Northwest Spain) by Applying PCA

Molecules 2022, 27(20), 7000

Wine is a complex matrix composed of numerous substances and color has an important influence on its quality and consumer acceptance. Color is affected by numerous factors such as pre-fermentation and fermentation operations, ageing, contact or addition of certain substances. In this study, different chromatic parameters were determined in 99 wines (58 red and 41 white) made from Galician (Northwest Spain) grape varieties. These parameters were obtained by using simple, rapid, and inexpensive spectrophotometric methodologies: color intensity, hue, total polyphenols content (Total Polyphenol Index TPI, Folin–Ciocalteu index, FCI), total anthocyans, total tannins, and color coordinates measured by the CIELab system. The influence of ageing in barrels (red wines) or using chips (white and red wines) on these parameters was also studied. A principal component analysis (PCA) was carried out to characterize the wines according to their chromatic characteristics. Application of PCA to the experimental data resulted in satisfactory classifications of studied white and red wines according to the cited enological practices.

Fungicide residues affect the sensory properties and flavonoid composition of red wine

Journal of Food Composition and Analysis, 66 (2018) 185-192

doi.org/10.1016/j.jfca.2017.12.021

The influence of four fungicide treatments [viz., metrafenone, boscalid + kresoxim-methyl, fenhexamid and mepanipyrim, which are typically used to control downy mildew (Plasmopara viticola) and grey mould (Botrytis cinerea)] on the composition of Tempranillo red wines was assessed by examining changes in phenolic composition, colour and aroma profile in wines from pesticide-treated grapes in relation to control wines made from untreated grapes. The results were also compared with those for wine of a previous vintage in order to ascertain whether fungicide-related changes were comparable to vintage-related changes. Only the boscalid + kresoxim-methyl treatment led to significant differences in wine of the 2013 vintage; thus, it increased the contents in monomeric anthocyanins (58%) and flavan-3-ols (36%), and also colour lightness (20%), but decreased the contribution of the ripe (42%) and fresh fruits (59%) odorant series. These results seemingly confirm that the presence of boscalid + kresoxim-methyl residues in must impairs the sensory quality of the resulting wine by diminishing its brightness and aroma. Differences varied markedly between years, which suggests that the course of the fermentation process is influenced not only by the composition of the grapes but also by the presence of the fungicide.

Lipid characteristics of dry-cured “Tocino” during the manufacturing process. Effects of salting intensity and ripening temperature

Journal of Food Composition and Analysis, 52 (2016) 33–43

http://dx.doi.org/10.1016/j.jfca.2016.07.005

The fatty acid composition, the lipid characteristics and the colour parameters of Tocino, a salted and ripened meat product made from subcutaneous backfat from pig, were studied throughout manufacturing of the product. The effects of the ripening temperature and of the duration of the salting process were also studied. Ripening process caused a significant (P < 0.001) decrease in the total and some individual polyunsaturated fatty acids (C18:2n-6, C18:3n-3, C20:2n-6, C20:3n-6, C20:4n-6, and C20:3n-3), particularly in the polar lipid fraction (total polyunsaturated fatty acids descended from 13.6 to 3.5% of total methyl esters). Increased ripening temperature (from 8 to 12 °C) and longer duration of salting (from 2 to 4 days) caused a significantly greater decrease in the content of polyunsaturated fatty acids. The nutritional and health index values indicated that Tocino is not a healthy product. During the ripening stage, Tocino underwent moderate lipolysis and very intense lipid oxidation (final values of 3.57–5.09 mg KOH/g of fat and 0.84–1.16 mg malondialdehyde/kg). Increasing the ripening temperature significantly increased (P < 0.001) both lipolysis and fat oxidation, while increasing the duration of salting only had a significant positive effect on oxidation processes. Longer ripening times led to a significant increase (P < 0.001) in the b* values (from 8.81 to 18.7–23.7) and significant decreases in the a* (from 7.10 to −3.31 – −4.04) and L* (from 81.5 to 66.4–70.2) values.

Oxidation of edible animal fats. Comparison of the performance of different quantification methods and of a proposed new semi-objective colour scale-based method

Food Chemistry, 217 (2017) 743–749

http://dx.doi.org/10.1016/j.foodchem.2016.09.009

The agreement among the results determined for the main parameters used in the evaluation of the fat auto-oxidation was investigated in animal fats (butter fat, subcutaneous pig back-fat and subcutaneous ham fat). Also, graduated colour scales representing the colour change during storage/ripening were developed for the three types of fat, and the values read in these scales were correlated with the values observed for the different parameters indicating fat oxidation.

In general good correlation among the values of the different parameters was observed (e.g. TBA value correlated with the peroxide value: r = 0.466 for butter and r = 0.898 for back-fat). A reasonable correlation was observed between the values read in the developed colour scales and the values for the other parameters determined (e.g. values of r = 0.320 and r = 0.793 with peroxide value for butter and back-fat, respectively, and of r = 0.767 and r = 0.498 with TBA value for back-fat and ham fat, respectively).

The measure and control of effects of botryticides on phenolic profile and color quality of red wines

Food Control 2015, 50, 942-948

The effect of the residues of two fungicides (mepanipyrim and fenhexamid) on the color and phenolic profile of Tempranillo and Graciano red wines has been studied. To evaluate possible modifications in color and phenolic composition of wines, control wines (not treated) and wines elaborated with spiked musts were analyzed. Thereby, changes in the color parameters of CIELab space were observed in the wines treated with mepanipyrim and also in Tempranillo wines treated with fenhexamid. In general, the anti-fungal substances had different effects depending on the cultivar and on the phenolic compound analyzed; being monomeric anthocyanins and flavan-3-ol monomers the compounds more affected by the presence of these fungicides.