Optimization of the Extraction Methodology of Grape Pomace Polyphenols for Food Applications.

This study aims to take advantage of the wine industry by-products and extract bioactive compounds from grape pomace by applying methodologies susceptible to be integrated easily into industrial workflows because of the association with standard instrumentation and facilities, while the main factors affecting the efficiency of the process have been optimized. The sampling consisted of two grape varieties: 'Touriga Nacional' and 'Sousão'. A response surface methodology (RSM) method was used to optimize the extraction conditions based on three independent variables according to the chemical characteristics and stability/lability traits associated with polyphenols; the main bioactive phytochemical in grape pomace: solvent (50%, 70%, and 90% ethanol); temperature (20 °C, 40 °C, and 60 °C); and pH (0.5% HCl, 2% HCl, and 3.5% HCl). The phytochemical profile, as well as the radical scavenging and reducing powers were determined on 27 different samples. The highest yield and antioxidant activity corresponded to extracts obtained at 60 °C using 3.5% HCl and 70% ethanol. The values for total phenols and flavonoids were 44.93 mg of gallic acid equivalents (GAE) and 22.95 mg of catechins equivalents (CE) per gram, respectively. Concerning the evaluation of antioxidant capacity using various assays such as ABTS, DPPH, and FRAP, the results obtained were 0.30, 0.43, and 0.36 mmol of Trolox equivalent antioxidant capacity (TEAC) per gram, correspondingly. The analysis of the extract obtained with the best extraction performance using these parameters via High-Performance Liquid Chromatography-Mass Spectrometry has been also performed, allowing us to identify fourteen (14) compounds, including phenolic acids (n = 3), flavonols (n = 7), and anthocyanins (n = 4). As a result of this process, the best conditions for the production of a natural and environmentally friendly dye, not only avoiding waste but also reusing these by-products, were achieved.

Seed Phytochemical Profiling of Three Olive Cultivars, Antioxidant Capacity, Enzymatic Inhibition, and Effects on Human Neuroblastoma Cells (SH-SY5Y).

This work evaluated the phytochemical composition of olive seed extracts from different cultivars ('Cobrançosa', 'Galega', and 'Picual') and their antioxidant capacity. In addition, it also appraised their potential antineurodegenerative properties on the basis of their ability to inhibit enzymes associated with neurodegenerative diseases: acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase (TYR). To achieve this goal, the phenolic composition of the extracts was determined through high-performance liquid chromatography coupled with photodiode-array detection and electrospray ionization/ion trap mass spectrometry (HPLC-DAD-ESI/MSn). The antioxidant capacity was assessed by two different methods (ABTS•+ and DPPH•), and the antineurodegenerative potential by the capacity of these extracts to inhibit the aforementioned related enzymes. The results showed that seed extracts presented a high content of phenolic compounds and a remarkable ability to scavenge ABTS•+ and DPPH•. Tyrosol, rutin, luteolin-7-glucoside, nüzhenide, oleuropein, and ligstroside were the main phenolic compounds identified in the extracts. 'Galega' was the most promising cultivar due to its high concentration of phenolic compounds, high antioxidant capacity, and remarkable inhibition of AChE, BChE, and TYR. It can be concluded that olive seed extracts may provide a sustainable source of bioactive compounds for medical and industrial applications.

Phytochemical and antioxidant analysis of medicinal and food plants towards bioactive food and pharmaceutical resources.

Plants with medicinal properties play an increasingly important role in food and pharmaceutical industries for their functions on disease prevention and treatment. This study characterizes the phenolic composition and antioxidant activity of seven medicinal and food plants, including the leaves of Salvia officinalis L., Rosmarinus officinalis L., Olea europaea L., and Punica granatum L., as well as the leaves and young stems of Ruta graveolens L., Mentha piperita L., and Petroselinum crispum, Mill., by using colorimetric, chromatographic, and spectrophotometric assays. Results revealed that the hydro-methanolic leaf extracts of P. granatum (pomegranate) displayed the highest content of total phenols (199.26 mg gallic acid per gram of plant dry weight), ortho-diphenols (391.76 mg gallic acid per gram of plant dry weight), and tannins (99.20 mg epicatechin per gram of plant dry weight), besides a higher content of flavonoids (24 mg catechin per gram of plant dry weight). The highest antioxidant capacity measured by ABTS, DPPH, and FRAP (2.14, 2.27, and 2.33 mM Trolox per gram of plant dry weight, respectively) methods was also obtained in pomegranate leaf extracts, being 4-200 times higher than the other species. Such potent antioxidant activity of pomegranate leaves can be ascribed to the presence of different types of phenolic compounds and the high content in tannins, whilst phenolic acids and flavonoids were found to be the dominant phenolic classes of the other six plants. Consequently, despite the well-known antioxidant properties of these plant species, our study suggests pomegranate leaf can stand out as a relatively more valuable plant source of natural bioactive molecules for developing novel functional food-pharma ingredients, with potential for not only promoting human health but also improving bio-valorization and environment.

New grape stems' isolated phenolic compounds modulate reactive oxygen species, glutathione, and lipid peroxidation in vitro: Combined formulations with vitamins C and E.

The antioxidant potential of grape (Vitis vinífera L.) stems has been reported in the last decade although no identification of the individual compounds responsible for such action has been done. In this work, polyphenolic extract of grape stems was processed resorting to semi-preparative HPLC, allowing to obtain 5 purified polyphenols (caftaric acid, malvidin-3-O-glucoside, quercetin-3-O-glucuronide, mailvidin-3-O-(6-O-caffeoyl)-glucoside, and Σ-viniferin), which were fully characterized by HPLC-PDA-ESI-MSn. Isolated compounds were featured on their radical scavenging capacity (DPPH and ABTS), cell viability, anti-inflammatory activity, and capacity to modulate the level of reactive oxygen species, glutathione, lipid peroxidation, and overall oxidative stress in a biological model (human keratinocytes) in vitro, under basal and oxidative conditions. The results obtained noticed the combinations malvidin-3-O-glucoside+Vitamin E and quercetin-3-O-glucuronide+vitamin C as the most effective, allowing to improve the capacity of complete extracts or individual compounds, and being candidates to be used in the development of new functional products.

New grape stems-based liqueur: Physicochemical and phytochemical evaluation.

A number of traditional liqueurs are obtained by maceration of red fruits in aqueous ethanol liquor, namely sloe berries or sour cherry. On the other hand, the exploration of residual plant material derived from the winery industry (grape (Vitis vinifera L.) stems), which has been regarded as an interesting source of colored and uncolored (poly)phenols, could lead to an industrial alternative to the traditional distilled spirits produced, with valuable physicochemical and phytochemical properties. In the present work, vinification residues (grape stems) were used to produce a new beverage. The evaluation of the physic-chemical characteristics and phytochemical composition as well as the evolution of the determined parameters during maceration (90 and 180 days) allowed a number of interesting bioactive compounds to be identified. This new beverage is a liqueur with a high retention of phenolic compounds (ortho-diphenols, flavanols, flavonols, and anthocyanins), with interesting physic-chemical characteristics, that revealed significant antioxidant activity.

Discrimination and characterisation of extra virgin olive oils from three cultivars in different maturation stages using Fourier transform infrared spectroscopy in tandem with chemometrics.

A methodology based on Fourier transform infrared (FTIR) spectroscopy, combined with multivariate analysis methods, was applied in order to monitor extra virgin olive oils produced from three distinct cultivars on different maturation stages. For the first time, this kind of methodology is used for the simultaneous discrimination of the maturation stage, and different cultivars. Principal component analysis and discriminant analysis were utilised to create a model for the discrimination of olive oil samples. Partial least squares regression was employed to design calibration models for the determination of chemical parameters. The performance of these models was based on the multiple coefficient of determination (R(2)), the root mean square error of calibration (RMSEC) and root mean square error of cross validation (RMSECV). The prediction models for the chemical parameters resulted in a R(2) ranged from 0.93 to 0.99, a RMSEC ranged from 1% to 4% and a RMSECV from 2% to 5%. It has been shown that this kind of approach allows to distinguish the different cultivars, and to clearly discern the different maturation stages, in each one of these distinct cultivars. Furthermore, the results demonstrated that FTIR spectroscopy in tandem with chemometric techniques allows the creation of viable and accurate models, suitable for correlating the data collected by FTIR spectroscopy, with the chemical composition of the EVOOs, obtained by standard methods.

Short wavelength Raman spectroscopy applied to the discrimination and characterization of three cultivars of extra virgin olive oils in different maturation stages.

Extra virgin olive oils produced from three cultivars on different maturation stages were characterized using Raman spectroscopy. Chemometric methods (principal component analysis, discriminant analysis, principal component regression and partial least squares regression) applied to Raman spectral data were utilized to evaluate and quantify the statistical differences between cultivars and their ripening process. The models for predicting the peroxide value and free acidity of olive oils showed good calibration and prediction values and presented high coefficients of determination (>0.933). Both the R(2), and the correlation equations between the measured chemical parameters, and the values predicted by each approach are presented; these comprehend both PCR and PLS, used to assess SNV normalized Raman data, as well as first and second derivative of the spectra. This study demonstrates that a combination of Raman spectroscopy with multivariate analysis methods can be useful to predict rapidly olive oil chemical characteristics during the maturation process.