Metal nanoparticles based lab-on-paper for phenolic compounds evaluation with no sample pretreatment. Application to extra virgin olive oil samples.

In this work, a low-cost, disposable, and portable lab-on-paper device is proposed to simultaneously quantify total polyphenol content (TPC) and antioxidant capacity (AOC) in 15 min; the assay requires no pre-treatment of the samples. The lab-on-paper device fabrication has been carried out employing a xurography-based benchtop microfabrication technology using low-cost materials as chromatography paper and polymeric sheets. Extra virgin olive oil (EVOO) phenolic compounds' represents a nutritional added value, nevertheless, the high lipidic content hinders their direct and rapid analysis, resulting in an extremely challenging sample. The realized lab-on-paper allows to perform the dual TPC and AOC determination in three simple steps: (i) sample loading, (ii) analytes transport to the analysis spot, and (iii) double colorimetric analysis exploiting the growth of AuNPs and AgNPs on paper mediated by phenolic compounds. Signal acquisition is achieved using a standard digital camera. The dual colorimetric assay is able to detect phenolic compounds in the 25-500 mg L-1 range with limits of detection ≤6 mg L-1 and good reproducibility (RSDs ≤11%). Direct analysis of EVOO samples (n = 30) correlated well (r > 0.92) with conventional spectrophotometric methods for TPC and AOC determination.

Role of Polyphenols and Carotenoids in Endothelial Dysfunction: An Overview from Classic to Innovative Biomarkers.

Nowadays, the dramatically increased prevalence of metabolic diseases, such as obesity and diabetes mellitus and their related complications, including endothelial dysfunction and cardiovascular disease, represents one of the leading causes of death worldwide. Dietary nutrients together with healthy lifestyles have a crucial role in the endothelium health-promoting effects. From a growing body of evidence, active natural compounds from food, including polyphenols and carotenoids, have attracted particular attention as a complementary therapy on atherosclerosis and cardiovascular disease, as well as preventive approaches through the attenuation of inflammation and oxidative stress. They mainly act as radical scavengers by promoting a variety of biological mechanisms, such as improvements in endothelial function, blood pressure, platelet activity, and insulin sensitivity, and by modulating various known biomarkers. The present review highlights the role of polyphenols and carotenoids in early endothelial dysfunction with attention to their beneficial effect in modulating both classical and recent technologically generated emerging biomarkers. These, alone or in combination, can play an important role in the prediction, diagnosis, and evolution of cardiovascular disease. However, a main challenge is to speed up early and prompt new interventions in order to prevent or slow down disease progression, even with an adequate intake of bioactive compounds. Hence, there is an urgent need of new more validated, appropriate, and reliable diagnostic and therapeutic biomarkers useful to diagnose endothelial dysfunction at an earlier stage.

Chemical-nutritional quality and oxidative stability of milk and dairy products obtained from Friesian cows fed with a dietary supplementation of dried grape pomace.

BACKGROUND: The aim of the study was to evaluate the nutritional properties of milk and cheese obtained from Friesian cows fed with a diet supplemented with dried grape pomace, a by-product of the oenological industry, which is very rich in polyphenols. This approach is inspired by the increasing interest in foods containing functional ingredients that may have beneficial effects on human health. During the testing period, analyses of the chemical and nutritional properties of milk and dairy products derived from it were performed; particular attention was given to the effect of cheese ripening on the oxidative stability and fermentation process, evaluating respectively the presence of malondialdehyde and γ-aminobutyric acid. RESULTS: Dietary enrichment with grape pomace did not affect the milk composition but induced modifications in the fatty acid profiles in both milk and cheese with an increase in concentration of linoleic acid, trans-vaccenic acid, rumenic acid and total n-6 fatty acids. Moreover, after 30 days of cheese ripening, an increased oxidative stability and an increased concentration of γ-aminobutyric acid were found. CONCLUSIONS: Our results indicated a general improvement in nutritional parameters of milk and related cheese obtained from Friesian cows that received the feeding enrichment with dried grape pomace. Further analysis should be performed to improve knowledge of the chemical and microbiological mechanisms at the source of these findings. © 2019 Society of Chemical Industry.

Rumen microbiome in dairy calves fed copper and grape-pomace dietary supplementations: Composition and predicted functional profile.

The rumen microbiome is fundamental for the productivity and health of dairy cattle and diet is known to influence the rumen microbiota composition. In this study, grape-pomace, a natural source of polyphenols, and copper sulfate were provided as feed supplementation in 15 Holstein-Friesian calves, including 5 controls. After 75 days of supplementation, genomic DNA was extracted from the rumen liquor and prepared for 16S rRNA-gene sequencing to characterize the composition of the rumen microbiota. From this, the rumen metagenome was predicted to obtain the associated gene functions and metabolic pathways in a cost-effective manner. Results showed that feed supplementations did alter the rumen microbiome of calves. Copper and grape-pomace increased the diversity of the rumen microbiota: the Shannon's and Fisher's alpha indices were significantly different across groups (p-values 0.045 and 0.039), and Bray-Curtis distances could separate grape-pomace calves from the other two groups. Differentially abundant taxa were identified: in particular, an uncultured Bacteroidales UCG-001 genus and OTUs from genus Sarcina were the most differentially abundant in pomace-supplemented calves compared to controls (p-values 0.003 and 0.0002, respectively). Enriched taxonomies such as Ruminiclostridium and Eubacterium sp., whose functions are related to degradation of the grape- pomace constituents (e.g. flavonoids or xyloglucan) have been described (p-values 0.027/0.028 and 0.040/0.022 in Pomace vs Copper and Controls, respectively). The most abundant predicted metagenomic genes belonged to the arginine and proline metabolism and the two- component (sensor/responder) regulatory system, which were increased in the supplemented groups. Interestingly, the lipopolysaccharide biosynthetic pathway was decreased in the two supplemented groups, possibly as a result of antimicrobial effects. Methanogenic taxa also responded to the feed supplementation, and methane metabolism in the rumen was the second most different pathway (up-regulated by feed supplementations) between experimental groups.

Antioxidant Properties of Oak Bracket Mushroom, Pseudoinonotus dryadeus (Higher Basidiomycetes): A Mycochemical Study.

A complex mixture of free fatty acids (1), cerevisterol (2), a sphingosine (3), and a complex mixture of diacylglycerophospholipids (4) were isolated from the fruiting body of the basidiomycete mushroom Pseudoinonotus dryadeus and subjected to spectroscopic analyses. The antioxidant activities of the whole extract of the fungus, of the isolated fractions, and of compounds 1-4 were evaluated in two in vitro model systems: 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide anion. In each systems, the extract of fungus and compound 2 showed the same free radical scavenging activity (with SC50 data of 18.27 µg/mL and 5.75 µg/mL, respectively) compared with the positive control quercetin (DPPH assay). Compounds 1-4 were isolated from P. dryadeus for the first time.

Lipid Metabolites from the Mushroom Meripilus giganteus.

The phytochemical investigation of the methanolic extract of the white rot fungus Meripilus giganteus resulted in the isolation and identification of complex mixtures of free fatty acids (1), monoacylglycerols (2), cerebrosides (3), ergosterol (4) and ergosterol peroxide (5). The structures of the isolated lipid metabolites (1-5) were determined by chemical and spectroscopic methods. The antioxidant activity of the whole MeOH extract of the fungus was evaluated through in vitro model systems, such as 2,2-diphenyl-l-picrylhydrazyl (DPPH) and superoxide anion. In all two systems, the results indicated that the extract of the fungus showed the same free-radical-scavenging activity with SC50 data of 47.70 µg/mL, compared with the positive control quercetin (DPPH assay). None of the isolated compounds (1-5) showed a significant activity. Compounds 2-4 were isolated from Meripilus giganteus for the first time.

Stability of iodine during cooking: investigation on biofortified and not fortified vegetables.

Biofortification of food crops through fertilization and salt iodization are key strategies for the prevention and control of iodine deficiency disorder. However, considerable losses of iodine can occur during processing. In this study, the stability of iodine in biofortified potatoes, carrots and tomatoes was evaluated during different domestic cooking procedures, as this matter was poorly discussed in literature. The stability of iodized salt during baking and boiling of carrots and potatoes not fortified was also investigated. All the adopted cooking procedures have proven to be suitable to preserve the iodine content in biofortified vegetables. During boiling test with iodized salt, neither potatoes nor carrots were able to absorb iodine added with salt, probably owing to the losses occurred during cooking. On the contrary, baking test on potatoes has not caused a significant degradation of iodized salt, and no significant differences in iodine concentration were detected before and after cooking.

Chlorophylls in olive and in olive oil: chemistry and occurrences.

The chlorophylls are responsible for the characteristic green color of the olive fruits and their products. Virgin olive oil (VOO) is obtained from processing olives only by mechanical and physical means under conditions ensuring that the natural characteristics of the fruit composition are maintained as far as possible. In terms of the total chlorophyll content of oil, the extraction process entails a loss of chlorophyll of up to 80%. Many factors, both agronomical and technological, can affect the presence of green pigments in VOO. The analysis of green pigments in olives and/or oil requires an initial phase of extraction of these compounds from the solid and fluid matrix, followed by the selective separation and subsequent identification of the different components of the chlorophyll fraction. The aim of this review article is to summarize and critically analyze the available information about chlorophylls in VOO.

Visible and near-infrared absorption spectroscopy by an integrating sphere and optical fibers for quantifying and discriminating the adulteration of extra virgin olive oil from Tuscany.

Because of its high price, extra virgin olive oil is frequently targeted for adulteration with lower quality oils. This paper presents an innovative optical technique capable of quantifying and discriminating the adulteration of extra virgin olive oil caused by lower-grade olive oils. An original set-up for diffuse-light absorption spectroscopy in the wide 400-1,700 nm spectral range was experimented. It made use of an integrating sphere containing the oil sample and of optical fibers for illumination and detection; it provided intrinsically scattering-free absorption spectroscopy measurements. This set-up was used to collect spectroscopic fingerprints of authentic extra virgin olive oils from the Italian Tuscany region, adulterated by different concentrations of olive-pomace oil, refined olive oil, deodorized olive oil, and refined olive-pomace oil. Then, a straightforward multivariate processing of spectroscopic data based on principal component analysis and linear discriminant analysis was applied which was successfully capable of predicting the fraction of adulterant in the mixture, and of discriminating its type. The results achieved by means of optical spectroscopy were compared with the analysis of fatty acids, which was carried out by standard gas chromatography.

Effects of fly attack (Bactrocera oleae) on the phenolic profile and selected chemical parameters of olive oil.

The phenolic fraction of virgin olive oil influences both its quality and oxidative stability. One of the principal threats of the quality of olive fruit is the olive fly ( Bactrocera oleae) as it alters the chemical composition. The attack of this olive pest has been studied in order to evaluate its influence on the quality of virgin olive oil (free acidity, peroxide value, fatty acid composition, water content, oxidative stability, phenols, and antioxidant power of phenolic fraction). The study was performed using several virgin olive oils obtained from olives with different degrees of fly infestation. They were acquired in different Italian industrial mills from the Abruzzo region. Qualitative and quantitative analyses of phenolic profiles were performed by capillary electrophoresis-diode array detection, and electrochemical evaluation of the antioxidant power of the phenolic fraction was also carried out. These analyses demonstrated that the degree of fly attack was positively correlated with free acidity ( r = 0.77, p < 0.05) and oxidized products ( r = 0.58, p < 0.05), and negatively related to the oxidative stability index ( r = -0.54, p < 0.05) and phenolic content ( r = -0.50, p < 0.05), mainly with secoiridoid compounds. However, it has been confirmed that the phenolic fraction of olive oil depends on several parameters and that a clear correlation does not exist between the percentages of fly attack and phenolic content.

High-performance liquid chromatographic analysis of chlorophylls, pheophytins and carotenoids in virgin olive oils: chemometric approach to variety classification.

This work evaluate the possibility to get from the quali-quantitative determination of the pigments contained in monovarietal olive oils (chlorophylls, pheophytins and carotenoids) and from the multivariate statistical analysis of these measures, parameters able to distinguish within the cultivars. The chemometric variables used have concurred to obtain preliminary interesting results. Liquid-phase distribution and solid-phase extraction/purification procedures has been compared: recoveries for both are resulted higher than 94% for all the pigment classes and the R.S.D. values were below 10%. HPLC analysis, allowing the simultaneous pigment determination, and fluorescence detection, allowing a better green pigments measure (detection limits from 5 to 80ppb), are revealed a fundamental solution.