Parámetros de calidad de aceites de oliva de las variedades de aceitunas griegas Koroneiki y Megaritiki con hueso y deshuesadas con diferente grado de maduración

Virgin olive oil is a natural functional food and its beneficial role in health as an integral ingredient of the Mediterranean diet is universally recognized. The effects of olive pitting, degree of ripeness and variety (Greek varieties Koroneiki and Megaritiki) were investigated on the physicochemical characteristics, antioxidant constituent contents and capacity and on the fatty acid profile of olive oil. Ripeness resulted in a decrease (P < 0.05) in phenolic and tocopherol contents and the unsaturated/saturated and C18:1ω-9/C18:2ω-6 fatty acid ratios. The pitting technique resulted in a significant increase in phenolic and tocopherol contents, in most cases, without significantly affecting the fatty acid profile and sums. Olive oils from the Koroneiki variety showed significantly higher (P < 0.05) monounsaturated/polyunsaturated fatty acid ratios, which are particularly important for the stability of the oil against oxidation. It was concluded that olive oil from pitted olives maintains a high content in bioactive compounds and a high level of antioxidant activity.El aceite de oliva virgen es un alimento funcional natural cuyo papel como ingrediente esencial de la dieta mediterránea, con propiedades beneficiosas para la salud, ha sido reconocido universalmente. Se ha estudiado el efecto del deshuesado de las aceitunas, grado de maduración y variedad (variedades griegas Koroneiki y Megaritiki) sobre las características físico-químicas, perfil de ácidos grasos y capacidad de los componentes antioxidantes de los aceites de oliva. La maduración ocasionó una disminución (P < 0,05) del contenido de fenoles y tocoferoles y de la relación de ácidos insaturados/ saturados así como de la relación de los ácidos C18:1ω-9/C18:2ω6. El deshuesado incrementa significativamente el contenido fenólico y de tocoferoles, sin afectar significativamente, en la mayoría de los casos, al perfil y cantidad de ácidos grasos. Los aceites de oliva de la variedad Koroneiki mostraron relaciones de ácidos grasos monoinsaturados/poliinsaturados significativamente mayores (p < 0,05) que son particularmente importantes para la estabilidad del aceite frente a la oxidación. En conclusión, el aceite de oliva deshuesado mantiene un alto contenido de compuestos bioactivos y un alto nivel de actividad antioxidante

Development of a green methodology for simultaneous extraction of polyphenols and pigments from red winemaking solid wastes (Pomace) using a novel glycerol-sodium benzoate deep eutectic solvent and ultrasonication pretreatment

In this examination, two glycerol-based deep eutectic solvents (DESs) were tested for their efficiency in the recovery of antioxidant polyphenols and anthocyanin pigments from red grape pomace (RGP). The two DESs synthesized had sodium acetate and sodium benzoate as hydrogen bond acceptors, to test the role of the hydrogen bond acceptor polarity on the extraction performance. Furthermore, the process was enhanced by an ultrasonication pretreatment stage. After initial testing with respect to water content, ultrasonication power and liquid-to-solid ratio, the DES composed of glycerol and sodium benzoate (GL-SBz) was shown to be significantly more efficient than the one made of glycerol and sodium acetate (GL-SAc). Further optimization of the extraction with regard to time and temperature demonstrated GL-SBz to be a highly effective solvent for the production of RGP extracts rich in polyphenols including gallic acid, catechin and quercetin, and pigments including malvidin 3-O-glucoside p-coumarate and malvidin 3-O-glucoside. The extracts produced also had significantly higher antiradical activity and reducing power compared to those generated with aqueous ethanol or water. From this study, evidence emerged regarding the role of the hydrogen bond acceptor nature in the extraction efficiency of polyphenols. The process developed is proposed as a green, high-performing methodology for the production of RGP extracts with enhanced polyphenolic content and antioxidant activity. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Integrated green process for the extraction of red grape pomace antioxidant polyphenols using ultrasound‐assisted pretreatment and β‐cyclodextrin

Winemaking is a process that generates a large volume of solid waste biomass, which is currently under extensive investigation as a bioresource of precious polyphenolic compounds. These substances are retrieved from vinification side streams principally by deploying solid–liquid extraction methods. In this frame, the present investigation had as objective the development of an alternative, green extraction process for polyphenols, through integration of ultrasonication as a pretreatment stage, and subsequent extraction with aqueous β‐cyclodextrin. Polyphenol recovery from red grape pomace (RGP) was shown to be significantly enhanced by ultrasonication pretreatment, and the use of β‐cyclodextrin effectively boosted the aqueous extraction. Under optimized conditions, established by response surface methodology, the maximum yield in total polyphenols was 57.47 mg GAE g−1 dm, at 80 °C, requiring a barrier of 10.95 kJ mol−1. The extract produced was significantly enriched in catechin and quercetin, compared to the aqueous extract, exhibiting also increased antiradical activity. These findings highlighted the value of the process developed for targeted recovery of certain polyphenols and the preparation of task‐specific extracts. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Stability of microemulsions containing red grape pomace extract obtained with a glycerol/sodium benzoate deep eutectic solvent

The valorization of red grape pomace is significant as grape is one of the most cultivated fruits worldwide and generated by-product quantities are enormous. For this purpose, numerous encapsulation techniques have been developed. However, the studies on microemulsions composed with deep eutectic solvent extracts are very limited. In this study, red grape pomace extract (RGPE) was first prepared by deep eutectic solvent extraction and characterized by HPLC analysis. Rutin, quercetin, catechin and caftaric acid were identified as the main non-pigment phenolic compounds. The RGPE was further encapsulated in microemulsions (MEs) following a low-energy approach using a mixture of low molecular weight surfactants, and the pseudo-ternary phase diagram was constructed. The physical and antioxidant stability of MEs containing 3-15 wt% RGPE was investigated for a period of 30 days. MEs were stable at an ambient temperature of 25 or 37°C. The radical scavenging activity of encapsulated RGPE was improved up to 13% compared to the free extract. Our results indicate that microemulsions provide protection of valuable phenolic constituents especially under elevated temperature conditions and can therefore be used as systems for applications in nutraceuticals or cosmetics.

Glycerol-Based Deep Eutectic Solvents for Simultaneous Organosolv Treatment/Extraction: High-Performance Recovery of Antioxidant Polyphenols from Onion Solid Wastes

Onion solid wastes (OSW) are a food side-stream with high polyphenolic load and distinguished polyphenolic profile. This study was conducted in order to explore a novel methodology of production of polyphenol-enriched extracts with antioxidant properties from OSW, using glycerol and green deep eutectic solvents (DES), composed of glycerol/citric acid and glycerol/sodium acetate. The organosolv process developed was appraised by establishing models based on severity, but also response surface methodology. Using a linear model, it was, for the first time, proposed that there is a direct correlation between the yield of the process in total polyphenols and the combined severity factor. Furthermore, response surface optimization enabled the establishment of linear models to predict the effects of time and temperature on the total polyphenol extraction yield. Out of the solvents tested, the DES composed of citric acid and glycerol was found to provide the highest yield in total polyphenols (87.90 ± 3.08 mg gallic acid equivalents per g dry mass) at significantly higher combined severity. However, the extraction efficiency of this solvent was virtually equal to that of the two other solvents tested. On the other hand, the polyphenolic composition of the extract obtained with the glycerol/citric acid DES was characterized by exceptionally high quercetin concentration. This extract also displayed the highest antioxidant activity. Based on the evidence emerged, it was proposed that OSW polyphenol extraction with the DES glycerol/citric acid could be used for production of extracts enriched in the bioactive flavonoid quercetin, with enhanced antioxidant activity. Moreover, using this green methodology, 27.59 ± 0.09 g of pure quercetin could be recovered out of 1 kg OSW. Thus, this methodology could be employed as a sustainable means of producing quercetin, through valorization of food wastes in a biorefinery context. © 2022 by the authors

Influence of toasting of oak chips on red wine maturation from sensory and gas chromatographic headspace analysis

Red wine from the Greek grape cultivar Aghiorghitiko, was aged in stainless steel with and without wood chips toasted to different degrees (heavily, medium, lightly) and in a 225L American standard oak barrel for 32 days. Headspace concentrations of four wood-derived congeners (furfural, guaiacol, cis and trans oak lactones) were determined over this period after which the wines were bottled, stored and subjected to sensory descriptive analyses. Of the 36 attributes for appearance, aroma and oral characters, 14 were significant in univariate analyses and differentiated wines in a multivariate (principal component analysis) product space explaining 72% variance in two factors. Wines from medium toast wood chips scored highest for woody, vegetative and smoky aromas and flavours but also for bitter taste and astringent mouthfeel and after 14 days had the highest headspace concentrations of furfural and cis oak lactone. Wood-related notes were ranked from heavily and lightly toasted chips, barrel and steel control

A quantitative analysis of the spatial and temporal evolution patterns of the bluetongue virus outbreak in the island of Lesvos, Greece, in 2014

Bluetongue virus (BTV) causes an infectious disease called bluetongue, a vector-borne viral disease of ruminants, which has major implications and causes severe economic damage due to its effect on livestock. These economic costs are mostly ascribed to the trade restrictions imposed during the epidemic period. In August 2014, an epidemic of bluetongue occurred in the island of Lesvos, Greece. The epidemic was severe and evolved over time, lasting until December 2014. The total cases of infected farms were 490, including a total number of 136,368 small ruminants. In this paper, we describe a bluetongue virus serotype 4 (BTV-4) epidemic and utilize Bayesian epidemic models to capture the spatio-temporal spread of the disease. Our study provides important insights into the drivers of BTV transmission and has implications for designing control strategies. The results showed strong spatial autocorrelations, with BTV being more likely to spread between farms located nearby. The spatial modelling results proposed a certain spatial radius (~12 km) around the onset of a similar epidemic for imposing restrictions on animal movement, which can be sufficient for the control of the disease and limit economic damage. © 2020 The Authors. Transboundary and Emerging Diseases published by Blackwell Verlag Gmb

Identification of polymorphisms of the CSN2 gene encoding β-casein in greek local breeds of cattle

This e research focused on the detection and identification of genetic polymorphisms in exon 7 of the β-casein CSN2 gene in blood samples from Greek Holstein cows and from local breeds of cattle, such as Vrachykeratiki, Katerinis, and Sykias. For this purpose, DNA was isolated from 780 blood samples obtained from Greek Holstein cows, 86 from three local breeds of cattle, namely Brachyceros, Katerinis, and Sykias, and 14 from Greek buffalo. The desired region of exon 7 was amplified by PCR, resulting in 121 and 251 bp products in bovine and buffalo samples. The PCR product was digested with restriction fragment length polymorphism (RFLP) on agarose gels. The restriction enzymes DdeI and TaqI were used. All of the blood samples had the amplified size. The results showed that 74.4% of the Greek Holstein cows had the A2A2 β-casein genotype, the three native breads Vrachykeratiki had 57.7%, and the other two had 100% of the A2A2 β-casein. From the 14 Greek buffalo, 100% had the A2A2 β-casein. © 2021 by the authors. Licensee MDPI, Basel, Switzerland