Carmelo García-Barroso’s research while affiliated with Universidad de Cádiz and other places

suitability of other types of woods for the ageing of these wines was carried out. To compare the characteristics of the alternative woods, an oloroso wine was aged in four groups of 16 L barrels made of French oak, Spanish oak, chestnut, as well as American oak as control, with intense and medium toasting. Phenolic and furanic compounds, organic acids, volatile compounds, color characteristics, total poly-phenol index and sensory analysis of wines aged for two months were analyzed. The results confirmed that the aged samples could be differentiated on the basis of their chemical composition, and that the use of alternative woods to age oloroso Sherry wines, and the level of wood toasting, had the potential to provide products with specific differences to the traditional aged in American oak. Furthermore, the organoleptic characteristics of these alternative wines were valued above a standard Sherry wine.

The colour of alcoholic beverages increases as they are aged in wood casks, due to the oxidation of the extracted phenols and tannic substances. In this paper, sixteen ageing experiments were carried out involving four different types of wood (American oak, French oak, Spanish oak and Chestnut), two toasting intensities (intense and medium toasting) and three initial wine distillates (holanda, wine spirit from a rectification column distillation and wine spirit from double distillation). Our experiments measured the CIEDE2000 colour difference as a control parameter for eight weeks. Four kinetic models were applied to better comprehend the evolution of the colour: Lagergren's first-order model, Peleg's pseudo-second-order model, an intra-particle diffusion model and a parabolic diffusion model. Differences on the non-linear correlation coefficients obtained by the Lagergren's and the Peleg's models show that the extractions are better fitted by the Peleg's model, leading to deduce that the colour obtained in the ageing process of the spirit is a second-order kinetic procedure. Differences between both diffusion models show that colours obtained from holandas are more strongly affected by side-reactions than colours obtained from wine spirits, probably due to their higher content in non-alcoholic compounds. Peleg's parameters show that toasting pre-treatments of wood also affect the kinetics of the colour obtained: intense toasted woods produce intense colours at the beginning of the ageing process, although medium toasted woods seem to produce more colour when equilibrium is reached.

The use of alternative types of wood has arisen for the aging of the Brandy de Jerez, on a pilot plant level. In particular, besides the use of American oak, two more types of oak have been studied, French oak and Spanish oak, allowed by the Technical File for the ID Brandy de Jerez, and chestnut, which, though it is not officially allowed, is a type of wood which had been traditionally used in the area for the aging of wines and distillates. All of them have been studied with different toasting levels: Intense toasting and medium toasting. The study of the total phenolic composition (TPI), chromatic characteristics, organic acids, and sensory analysis have proven that chestnut leads to distillates with a higher amount of phenolic compounds and coloring intensity than oak. This behavior is the opposite as regards the toasting of the wood. Among the different types of oak, Spanish oak produces aged distillates with a higher phenolic composition and a higher color intensity. Regarding tasting, the best-assessed samples were those aged with chestnut, French oak, and American oak, and the assessors preferred those who had used a medium toasting level to those with an intense level.

BACKGROUND Edible seaweeds are one of the most important resources that currently exist for their multiple uses and applications. Like other food types, during their storage there are significant changes in sensory characteristics associated with loss of freshness and with production and/or degradation of their volatile compounds. In this study, multiple headspace sorptive extraction (MHSSE) coupled with gas chromatography/mass spectrometry (GC/MS) detection has been applied to an edible green seaweed (Ulva rigida) in order to determine the evolution of volatile compounds during storage for 12 days at 4 or 16 °C. RESULTS The existing analytical methodology has been updated and validated for 18 additional compounds. At the end, 41 volatile compounds from different chemical families were quantified. Aldehydes, carboxylic acids and esters were the main classes found in U. rigida. Analytical and sensory data were submitted for statistical analysis. During storage, most volatile compounds were only affected by the number of storage days (P < 0.05), with significant decreases as storage time increased. Sensory analysis revealed significant changes in the samples stored for longer times (8, 10 and 12 days), with a clear influence of the boiled vegetable descriptor. CONCLUSION In order to get a successful preservation of seaweeds and to maintain their marine character during storage, both temperature and time should be carefully controlled. © 2019 Society of Chemical Industry

Abstract Jabuticaba is a very popular fruit in Brazil being a great source of compounds with considerable biological activities. Novel optimized ultrasound-assisted extraction (UAE) methods have been proposed for anthocyanins and total phenolic compounds from jabuticaba. A Box–Behnken experimental design (BBD) with a response surface methodology (RSM) was used to investigate the effect of six independent variables (solvent composition, solvent-to-sample ratio, ultrasound amplitude and cycle, pH, and temperature) on the UAE. Solvent composition was found to be the most significant variable for the extraction of both anthocyanins (51%) and total phenolic compounds (72%). The other optimum conditions for anthocyanins were as follows: pH 7.00, 39.8 ºC, 20:1.5 mL:g solvent-to-sample ratio, 34% ultrasound amplitude and cycle of 0.47 seconds. The optimum conditions for the extraction of phenolic compounds were: pH 7.00, 26.0 ºC, 20:1.5 (mL:g) solvent-to-sample ratio, 68.5% ultrasound amplitude and cycle of 0.5 seconds. The extraction kinetic was also evaluated. The developed methods showed a high precision, with coefficients of variation of less than 5% for both repeatability and intermediate precision (within-lab reproducibility). The applicability of the new methods was successfully evaluated on several fruits and jams from jabuticaba.

There are several phenolic compounds in rice grains providing benefits for human health. The concentration of phenolic compounds in rice are strongly affected by the polishing steps during rice production. A new sensitive ultra-performance liquid chromatography–ultraviolet-visible spectroscopy method with photodiode array detection protocol has been developed and validated for the quantitation of phenolic compounds in rice grains. Several working variables and two different columns were evaluated. Finally, a less than 3 min analysis time was developed to achieve enough resolution for the simultaneous determination of the 20 most common phenolic compounds in rice. The analytical properties for the separation method produced an adequate sensitivity for all phenolic compounds in the regular range for phenolics in rice: 0.5–100 mg L-1 (R2>0.997) with high precisions for both repeatability and intermediate precisions (CV less than 0.4% and 2.5% for retention time and the area of the peaks, respectively).

Brandy de Jerez is the most produced spirit in Spain. The rules of its Regulatory Council require the spirit to age in American oak casks that have previously contained any kind of sherry wine. This use, called seasoning, releases wine compounds into the spirit. Because of the differences among sherries, the organoleptic features of a brandy will be significantly different from any other depending on the seasoning. In addition, its specific features make it different from any other spirit. The chromatographic profiles of Brandy de Jerez are reported to be different depending on the seasonings through their ageing process. Different types of Brandy de Jerez have been characterised, regarding their seasoning, using chromatographic techniques. Applying statistical analysis, correlations between the chromatographic profiles and the seasonings have risen up. In addition, the profiles have demonstrated to possess a high degree of correlation with the ageing time of the samples.

Winemaking by-products are considered to be a rich source of bioactive compounds. Grape pomace is susceptible to microbial degradation due to the degree of residual moisture, so the drying of this pomace for conservation is considered to be an essential first step. Previous studies concerning the way in which drying affects winery by-products have produced contradictory results. In this study, a new methodology for drying grape pomace in a climatic chamber has been evaluated. Five red grape pomace varieties were dried in a climatic chamber at 40 °C and 10% relative humidity and the phenolic content and antioxidant activity of the dried and wet pomace samples were compared. The results indicate that this drying process is both feasible and beneficial because significant increases in the extractability of phenolic compounds and antioxidant activity were achieved.

Background: The two main acetification methodologies generally employed in the production of vinegar (surface and submerged cultures) were studied and compared for the production of orange vinegar. Polyphenols (UPLC/DAD) and volatiles compounds (SBSE-GC/MS) were considered as the main variables in the comparative study. Sensory characteristics of the obtained vinegars were also evaluated. Results: Seventeen polyphenols and twenty four volatile compounds were determined in the samples during both acetification processes. For phenolic compounds, analysis of variance showed significant higher concentrations when surface culture acetification was employed. However, for the majority of volatile compounds higher contents were observed for submerged culture acetification process, and it was also reflected in the sensory analysis, presenting higher scores for the different descriptors. Multivariate statistical analysis such as principal component analysis demonstrated the possibility of discriminating the samples regarding the type of acetification process. Polyphenols such as apigenin derivative or ferulic acid and volatile compounds such as 4-vinylguaiacol, decanoic acid, nootkatone, trans-geraniol, β-citronellol or α-terpineol, among others, were those compounds that contributed more to the discrimination of the samples. Conclusion: The acetification process employed in the production of orange vinegar has demonstrated to be very significant for the final characteristics of the vinegar obtained. So it must be carefully controlled to obtain high quality products.

The discovery of the impact of antioxidant compounds on health has led to the development of several methods based on different physiochemical processes for quantifying the antioxidant activity of samples. However, when comparing the antioxidant activity of samples, the use of alternative methods may lead to conflicting results. The aim of this study is to evaluate the antioxidant capacity of brandies, old wines and sweet wines by two methods: the first electrochemical method and the second based on photo-induced chemiluminescence, using various statistical approaches: correlation of data, the Bland-Altman test and FREML regression. The results obtained show that these two methods for evaluating antioxidant activity are not comparable. Only no commercial brandy shows statistically similar results, at a probability of 95 %, for the two methods.