Potential Prebiotic Effect of Inulin-Enriched Pasta after In Vitro Gastrointestinal Digestion and Simulated Gut Fermentation.

In the current study, the prebiotic potential of an innovative functional pasta enriched with 12% (w/w) inulin was investigated. To this aim, pasta was subjected to in vitro gastrointestinal digestion followed by simulated gut fermentation compared to the control pasta (CTRL) not containing inulin. The incorporation of inulin positively (p < 0.05) affected some organoleptic traits and the cooking quality of the final product, giving an overall score significantly higher than CTRL. The resultant essential amino acid content was similar in both pasta samples while the total protein content was lower in inulin-enriched pasta for the polymer substitution to durum wheat flour. The prebiotic potential of chicory inulin was preliminarily tested in in vitro experiments using seven probiotic strains and among them Lacticaseibacillus paracasei IMPC2.1 was selected for the simulated gut fermentation studies. The positive prebiotic activity score registered with the probiotic strain suggested the suitability of the inulin-enriched pasta with respect to acting as a prebiotic source favoring the growth of the probiotic strain and short chain fatty acid (SCFA) production. The present study contributes to broadening knowledge on the prebiotic efficacy of inulin when incorporated into a complex food matrix.

Liquid submerged fermentation by selected microbial strains for onion skins valorization and its effects on polyphenols.

Onion skins, actually recycled as organic fertilizers, could be used as a substrate in environmental-friendly bioprocesses to recover high-value bioactive compounds and food ingredients.In this work, a bioprospecting method was carried out including 94 bacterial and 45 yeast strains from several agri-food and environmental niches to verify their ability to grow on onion skins as unique nutrients source.Red and yellow onion skins were assessed by newly selected starter-driven liquid submerged fermentation assays mainly aimed at the release and modification of polyphenols through microbial activities. Fermented onion skins were also investigated as a inexpensive favourable source of microbial enzymes (amylases, proteases, lipases, esterases, cellulases, xylanases).In red onion skins, the treatment with Lactiplantibacillus plantarum TB 11-32 produced a slight increase of bioactive compounds in terms of total phenolics, whereas with the yeast strain Zygosaccharomyces mrakii CL 30 - 29 the quercetin aglycone content increased of about 25% of the initial raw material.In yellow onion skins inoculated, the highest content of phenolic compounds was detected with the yeast strain Saccharomyces cerevisiae En SC, while quercetin aglycone increased of about 60% of the initial raw material in presence of the bacterial strain L. plantarum C 180 - 34.In conclusion, the proposed microbial pre-treatment method can be a potential strategy to re-use onion skins as a fermentation substrate, and as a first step in the development of a biorefinery process to produce value-added products from onion by-products.

Comparative Analysis of Bioactive Compounds in Two Globe Artichoke Ecotypes Sanitized and Non-Sanitized from Viral Infections.

Globe artichoke ecotypes sanitized from plant pathogen infections are characterized by high vegetative vigor, productivity, and quality of capitula. The recent availability on the market of these plants has renewed the interest of farmers and pharmaceutical industries in the crop. Globe artichoke exhibits interesting nutraceutical properties due to the high content of health-promoting bioactive compounds (BACs), such as polyphenols, that could be extracted from waste biomass. The production of BACs depends on several factors including the plant portion considered, the globe artichoke variety/ecotype, and the physiological status of the plants, linked to biotic and abiotic stresses. We investigated the influence of viral infections on polyphenol accumulation in two Apulian late-flowering ecotypes "Locale di Mola tardivo" and "Troianella", comparing sanitized virus-free material (S) vs. naturally virus-infected (non-sanitized, NS) plants. Transcriptome analysis of the two ecotypes highlighted that differentially expressed genes (DEGs), in the two tested conditions, were mainly involved in primary metabolism and processing of genetic/environmental information. The up-regulation of the genes related to the biosynthesis of secondary metabolites and the analysis of peroxidase activity suggested that their modulation is influenced by the phytosanitary status of the plant and is ecotype-dependent. Conversely, the phytochemical analysis showed a remarkable decrease in polyphenols and lignin accumulation in S artichokes compared to NS plants. This unique study analyzes the potential of growing vigorous, sanitized plants, in order to have high amounts of 'soft and clean' biomass, finalized for BAC extraction for nutraceutical purposes. This, in turn, opens new perspectives for a circular economy of sanitized artichokes, in line with the current phytosanitary standards and sustainable development goals.

Characterization of Dextran Produced by the Food-Related Strain Weissella cibaria C43-11 and of the Relevant Dextransucrase Gene.

A metabolic feature of lactic acid bacteria (LAB) is the production of exopolysaccharides (EPSs), which have technological and functional properties of interest to the food sector. The present study focused on the characterization of the Weissella cibaria strain C43-11, a high EPS producer in the presence of sucrose, in comparison with a low-producing strain (C2-32), and on possible genetic regulatory elements responsible for the modulation of dextransucrase (dsr) genes expression. NMR analysis of the polymeric material produced by the C43-11 strain indicated the presence of dextran consisting mainly of a linear scaffold formed by α-(1-6) glycosidic linkages and a smaller amounts of branches derived from α-(1-2), α-(1-3), and α-(1-4) linkages. Molecular analysis of the dsr genes and the putative transcriptional promoters of the two strains showed differences in their regulatory regions. Such variations may have a role in the modulation of dsr expression levels in the presence of sucrose. The strong upregulation of the dsr gene in the C43-11 strain resulted in a high accumulation of EPS. This is the first report showing differences in the regulatory elements of the dsr gene in W. cibaria and indicates a new perspective of investigation to identify the regulatory mechanism of EPS production.

Plasticity, exudation and microbiome-association of the root system of Pellitory-of-the-wall plants grown in environments impaired in iron availability.

The investigation of the adaptive strategies of wild plant species to extreme environments is a challenging issue, which favors the identification of new traits for plant resilience. We investigated different traits which characterize the root-soil interaction of Parietaria judaica, a wild plant species commonly known as "Pellitory-of-the-wall". P. judaica adopts the acidification-reduction strategy (Strategy I) for iron (Fe) acquisition from soil, and it can complete its life cycle in highly calcareous environments without any symptoms of chlorosis. In a field-to-lab approach, the microbiome associated with P. judaica roots was analyzed in spontaneous plants harvested from an urban environment consisting in an extremely calcareous habitat. Also, the phenolics and carboxylates content and root plasticity and exudation were analyzed in P. judaica plants grown under three different controlled conditions mimicking the effect of calcareous environments on Fe availability: results show that P. judaica differentially modulates root plasticity under different Fe availability-impaired conditions, and that it induces, to a high extent, the exudation of caffeoylquinic acid derivatives under calcareous conditions, positively impacting Fe solubility.

Antioxidant and Pro-Oxidant Capacities as Mechanisms of Photoprotection of Olive Polyphenols on UVA-Damaged Human Keratinocytes.

A wide variety of polyphenols are reported to have considerable antioxidant and skin photoprotective effects, although the mechanisms of action are not fully known. Environmentally friendly and inexpensive sources of natural bioactive compounds, such as olive mill wastewater (OMWW), the by-product of olive-oil processing, can be considered an economic source of bioactive polyphenols, with a range of biological activities, useful as chemotherapeutic or cosmeceutical agents. Green strategies, such as the process based on membrane technologies, allow to recover active polyphenols from this complex matrix. This study aims to evaluate the antioxidant, pro-oxidant, and photoprotective effects, including the underlying action mechanism(s), of the ultra-filtered (UF) OMWW fractions, in order to substantiate their use as natural cosmeceutical ingredient. Six chemically characterized UF-OMWW fractions, from Italian and Greek olive cultivar processing, were investigated for their antioxidant activities, measured by Trolox Equivalent Antioxidant Capacity (TEAC), LDL oxidation inhibition, and ROS-quenching ability in UVA-irradiated HEKa (Human Epidermal Keratinocytes adult) cultures. The photoprotective properties of UF-OMWW were assayed as a pro-oxidant-mediated pro-apoptotic effect on the UVA-damaged HEKa cells, which can be potentially involved in the carcinogenesis process. All the UF-OMWW fractions exerted an effective antioxidant activity in vitro and in cells when administered together with UV-radiation on HEKa. A pro-oxidative and pro-apoptotic effect on the UVA-damaged HEKa cells were observed, suggesting some protective actions of polyphenol fraction on keratinocyte cell cultures.

Bioactive Phenolics and Antioxidant Capacity of Some Wild Edible Greens as Affected by Different Cooking Treatments.

The study aimed to assess the influence of three cooking methods (boiling, steaming, and microwave-cooking) on (i) composition in individual phenolic compounds, (ii) total phenolic content (TPC), and (iii) total antioxidant activity (TAA) of eight Mediterranean wild edible species (Asparagus acutifolius, Asphodeline lutea, Beta vulgaris, Helminthotheca echioides, Sonchus oleraceus, Taraxacum officinale, Urospermum picroides, Urtica dioica). In raw greens, several caffeic acid derivatives (chicoric, caftaric, chlorogenic, neochlorogenic, 1,5-and 3,5-dicaffeoylquinic acids) and flavonoids (glycosides of apigenin, luteolin, quercetin, isorhamnetin, kaempferol) were identified. Cooking treatments did not affect qualitative phenolic composition, while quantitative changes were recorded in some phenolic compounds and in TPC. Generally, boiling decreased TPC and TAA, while chicoric, caftaric, chlorogenic acids and quercetin-3-rutinoside increased in some species after steaming and microwave-cooking, showing positive correlation with TAA. Results confirmed steaming and microwave-cooking as mild procedures able to increase antioxidant capacity of some species, producing beneficial effects on their nutraceutical properties.

Characterization of Micronutrients, Bioaccessibility and Antioxidant Activity of Prickly Pear Cladodes as Functional Ingredient.

The Opuntia ficus indica (L.) (OFI) is used as a nutritional and pharmaceutical agent in various dietary and value added products. This study underlines the possible use of native prickly pear cladode powder as a functional ingredient for health-promoting food production. To summarise, chemical characterization of polyphenols, minerals and soluble dietary fibre was performed; furthermore, the antioxidant activity and bioaccessibility of polyphenols and minerals were assessed. Eleven compounds between phenolic acids and flavonoids were identified, with piscidic acid and isorhamnetin derivatives being the most abundant. Opuntia's dietary fibre was mainly constituted of mucilage and pectin, and was composed of arabinose, galactose, glucose, mannose, rhamnose, and xylose sugars. The polyphenols' bioaccessibility was very high: piscidic acid at 200%, eucomic and ferulic acids >110% and flavonoids from 89% to 100%. The prickly pear cladode powder is also a source of minerals, as cations (calcium, sodium, potassium and magnesium) and anions (sulphate and chloride), with high magnesium bioaccessibilty (93%). OFI powder showed good capacity of radical scavenging measured by DPPH and ABTS methods, with 740 and 775 µmol Trolox/100 g OFI, respectively. Finally, the presented results allow the consideration of this natural product as a source of several essential nutrients, with a possible use in the food industry as a functional ingredient.

Artichoke Polyphenols Produce Skin Anti-Age Effects by Improving Endothelial Cell Integrity and Functionality.

Artichoke is a characteristic crop of the Mediterranean area, recognized for its nutritional value and therapeutic properties due to the presence of bioactive components such as polyphenols, inulin, vitamins and minerals. Artichoke is mainly consumed after home and/or industrial processing, and the undersized heads, not suitable for the market, can be used for the recovery of bioactive compounds, such as polyphenols, for cosmetic applications. In this paper, the potential skin anti-age effect of a polyphenolic artichoke extract on endothelial cells was investigated. The methodology used was addressed to evaluate the antioxidant and anti-inflammatory activities and the improvement of gene expression of some youth markers. The results showed that the artichoke extract was constituted by 87% of chlorogenic, 3,5-O-dicaffeoylquinic, and 1,5-O-dicaffeoylquinic acids. The extract induced important molecular markers responsible for the microcirculation and vasodilatation of endothelial cells, acted as a potential anti-inflammatory agent, protected the lymphatic vessels from oxidative damage by ROS formation, and enhanced the cellular cohesion by reinforcing the tight junction complex. In addition, the artichoke extract, through the modulation of molecular pathways, improved the expression of genes involved in anti-ageing mechanisms. Finally, clinical testing on human subjects highlighted the enhancement by 19.74% of roughness and 11.45% of elasticity from using an artichoke extract cosmetic formulation compared to placebo cream.

Use of Olive Oil Industrial By-Product for Pasta Enrichment.

BACKGROUND: During recent years food industries generally produce a large volume of wastes both solid and liquid, representing a disposal and potential environmental pollution problem. OBJECTIVE: The goal of the study was to optimize, from both sensory and nutritional points of view, the formulation of durum wheat spaghetti enriched with an olive oil industrial by-product, indicated as olive paste. METHODS: Three consecutive steps were carried out. In the first one, the olive paste was air-dried at low temperature, milled to record olive paste flour and properly analyzed for its biochemical composition. In the second step, the olive paste flour was added to the pasta dough at 10% and 15% (w/w). In the last step, different concentrations of transglutaminase were added to enriched pasta (10% olive paste) to further improve the quality. Sensory properties and nutritional content of enriched and control pasta were properly measured. RESULTS: Spaghetti with 10% olive paste flour and 0.6% transglutaminase were considered acceptable to the sensory panel test. Nutritional analyses showed that addition of 10% olive paste flour to pasta considerably increased content of flavonoids and total polyphenols. CONCLUSIONS: The proper addition of olive paste flour and transglutaminase for pasta enrichment could represent a starting point to valorize olive oil industrial by-products and produce new healthy food products.

Signal transduction in artichoke [Cynara cardunculus L. subsp. scolymus (L.) Hayek] callus and cell suspension cultures under nutritional stress.

Stimulated production of secondary phenolic metabolites and proline was studied by using cell cultures of artichoke [Cynara cardunculus L. subsp. scolymus (L.) Hayek] submitted to nutritional stress. Artichoke cell cultures accumulated phenolic secondary metabolites in a pattern similar to that seen in artichoke leaves and heads (capitula). This paper shows that both callus and cell suspension cultures under nutritional stress accumulated phenolic compounds and proline, at the same time their biomass production was negatively affected by nutrient deficiency. The results obtained strongly suggest that plant tissues respond to nutrient deprivation by a defensive costly mechanism, which determines the establishment of a mechanism of trade-off between growth and adaptive response. Furthermore, the results of this research suggest that perception of abiotic stress and increased phenolic metabolites are linked by a sequence of biochemical processes that also involves the intracellular free proline and the oxidative pentose phosphate pathway. The main conclusion of this paper is that, once calli and cell suspension cultures respond to nutrient deficiency, in acclimated cells the establishment of a negative correlation between primary metabolism (growth) and secondary metabolism (defence compounds) is observed.

Fermented Apulian table olives: Effect of selected microbial starters on polyphenols composition, antioxidant activities and bioaccessibility.

The effects of fermentation by autochthonous microbial starters on phenolics composition of Apulian table olives, Bella di Cerignola (BDC), Termite di Bitetto (TDB) and Cellina di Nardò (CEL) were studied, highlighting also the cultivars influence. In BDC with starter, polyphenols amount doubled compared with commercial sample, while in TDB and CEL, phenolics remain almost unchanged. The main phenolics were hydroxytyrosol, tyrosol, verbascoside and luteolin, followed by hydroxytyrosol-acetate detected in BDC and cyanidine-3-glucoside and quercetin in CEL. Scavenger capacity in both DPPH and CAA assays, assessed the highest antioxidant effect for CEL with starters (21.7 mg Trolox eq/g FW; 8.5 µmol hydroxytyrosol eq/100 g FW). The polyphenols were highly in vitro bioaccessible (>60%), although modifications in their profile, probably for combined effect of environment and microorganisms, were noted. Finally, fermented table olives are excellent source of health promoting compounds, since hydroxytyrosol and tyrosol are almost 8 times more than in olive oil.

Real-time monitoring of glucose and phenols intestinal absorption through an integrated Caco-2TC7cells/biosensors telemetric device: Hypoglycemic effect of fruit phytochemicals.

An integrated device for real-time monitoring of glucose and phenols absorption, that consists of a sensors/biosensors system (SB) and a Caco-2TC7 human intestinal cell culture, is described in this study. The SB is composed of a glucose oxidase-based biosensor, a sentinel platinum sensor, a laccase/tyrosinase-based biosensor and a sentinel carbon sensor, all located in the basolateral compartment (BC) of a cell culture plate. Caco-2TC7 cells, differentiated on culture inserts, separated the apical compartment that simulates the intestinal lumen, from the BC which represented the bloodstream. The system recorded currents relative to glucose (1mM) absorption, obtaining bioavailability values (5.1%) comparable to HPLC analysis (4.8%). Phloridzin and phloretin, specific phenolic inhibitors of SGLT1 and GLUT2 glucose transporters, reduced the glucose transport of almost 10 times. They were minimally absorbed in the BC with a bioavailability of 0.13% and 0.49% respectively. The hypoglycemic potential of blueberry and pomegranate juices was also studied. In particular, the amount of glucose absorbed through the Caco-2TC7 monolayer was 8‰ for pomegranate and 1.7‰ for blueberry, demonstrating the potential hypoglycemic effect of the juices. Polyphenols absorption was also monitored by the SB and an increase was recorded during the first 50min in presence of both blueberry and pomegranate juices, then a constant decrease occurred. The proposed device has been developed as innovative tool for the dynamic monitoring of natural compounds effects on glucose absorption, in order to manage postprandial hyperglycemia.

Biophenols from Table Olive cv Bella di Cerignola: Chemical Characterization, Bioaccessibility, and Intestinal Absorption.

In this study, the naturally debittered table olives cv Bella di Cerignola were studied in order to (i) characterize their phenolic composition; (ii) evaluate the polyphenols bioaccessibility; (iii) assess their absorption and transport, across Caco2/TC7. LC-MS/MS analysis has confirmed the presence of hydroxytyrosol acetate, caffeoyl-6'-secologanoside, and comselogoside. In vitro bioaccessibility ranged from 7% of luteolin to 100% of tyrosol, highlighting the flavonoids sensitivity to the digestive conditions. The Caco2/TC7 polyphenols accumulation was rapid (60 min) with an efficiency of 0.89%; the overall bioavailability was 1.86% (120 min), with hydroxytyrosol and tyrosol the highest bioavailables, followed by verbascoside and luteolin. In the cells and basolateral side, caffeic and coumaric acids metabolites, probably derived from esterase activities, were detected. In conclusion, the naturally debittered table olives cv Bella di Cerignola can be considered as a source of bioaccessible, absorbable, and bioavailable polyphenols that, for their potential health promoting effect, permit inclusion of table olives as a functional food suitable for a balanced diet.

Carbon Fluxes between Primary Metabolism and Phenolic Pathway in Plant Tissues under Stress.

Higher plants synthesize an amazing diversity of phenolic secondary metabolites. Phenolics are defined secondary metabolites or natural products because, originally, they were considered not essential for plant growth and development. Plant phenolics, like other natural compounds, provide the plant with specific adaptations to changing environmental conditions and, therefore, they are essential for plant defense mechanisms. Plant defensive traits are costly for plants due to the energy drain from growth toward defensive metabolite production. Being limited with environmental resources, plants have to decide how allocate these resources to various competing functions. This decision brings about trade-offs, i.e., promoting some functions by neglecting others as an inverse relationship. Many studies have been carried out in order to link an evaluation of plant performance (in terms of growth rate) with levels of defense-related metabolites. Available results suggest that environmental stresses and stress-induced phenolics could be linked by a transduction pathway that involves: (i) the proline redox cycle; (ii) the stimulated oxidative pentose phosphate pathway; and, in turn, (iii) the reduced growth of plant tissues.

Polyphenols from artichoke heads (Cynara cardunculus (L.) subsp. scolymus Hayek): in vitro bio-accessibility, intestinal uptake and bioavailability.

Artichoke is a rich source of health promoting compounds such as polyphenols, important for their pharmaceutical and nutritional properties. In this study, the potential for bioavailability of the artichoke polyphenols was estimated by using both in vitro digestion and Caco-2 human intestinal cell models. In vitro digestive recoveries (bio-accessibility) were found to be 55.8% for total artichoke phenolics and in particular, 70.0% for chlorogenic acid, 41.3% for 3,5-O-dicaffeoylquinic acid, and 50.3% for 1,5-O-dicaffeoylquinic acid, highlighting potential sensitivity of these compounds to gastric and small intestinal digestive conditions. Uptake of artichoke polyphenols was rapid with peak accumulation occurring after 30 min with an efficiency of 0.16%, according to the poor uptake of dietary polyphenols. Some compounds, such as coumaric acid, caffeic acid and caffeic acid derivatives, were also detected in the basolateral side assuming extra and intracellular esterase activities on chlorogenic acid. Only apigenin-7-O-glucoside was transported through the Caco-2 monolayer demonstrating its bioavailability to the extent of 1.15% at 60 min. In addition, permeability coefficient (Papp = 2.29 × 10(-5) cm s(-1)), involving apical to basolateral transport of apigenin 7-O-glucoside, was calculated to facilitate estimation of transport through the Caco-2 monolayer. Finally, the mono and dicaffeoylquinic acids present in artichoke heads exert an antioxidant activity on the human low density lipoprotein system correlated to their chemical structure. In conclusion, the utilized in vitro models, although not fully responding to the morphological and physiological features of human in vivo conditions, could be a useful tool for investigating mechanistic effects of polyphenols released from the food matrix.

Verbascoside, isoverbascoside, and their derivatives recovered from olive mill wastewater as possible food antioxidants.

Olive oil processing industries generate substantial quantities of phenolic-rich byproducts, which could be valuable natural sources of antioxidants. This work is focused on the recovery and structural characterization of antioxidant compounds from olive mill wastewater (OMWW), a polluting byproduct of the olive oil production process. Phenolics were extracted from the waste material using a membrane technology coupled to low-pressure gel filtration chromatography on a Sephadex LH-20. The LH-20 fraction was, in turn, characterized for its phenolic composition by HPLC-DAD-MS/MS analyses. Verbascoside, isoverbascoside, ß-hydroxyverbascoside, ß-hydroxyisoverbascoside, and various oxidized phenolics were identified. Uptake of verbascoside, purified from the LH-20 fraction, by HT-29 cells, an established model system for studying drug transport properties, was also assayed. Finally, the antioxidant activities of the LH-20 fraction and verbascoside were characterized by two different techniques. Individual verbascoside was more active as a scavenger of reactive oxygen species and as a chemopreventive agent protecting low-density lipoproteins from oxidative damage than the LH-20 fraction.

Artichoke polyphenols induce apoptosis and decrease the invasive potential of the human breast cancer cell line MDA-MB231.

The human breast cancer cell line, estrogen receptor negative, MDA-MB231, was used to evaluate the antitumor effect of polyphenolic extracts from the edible part of artichokes (AEs). Treatment of cancer cells reduced cell viability and inhibited cell growth in a dose-dependent manner. Importantly, AEs did not have any effect on normal breast epithelial cell line, MCF10A. Chlorogenic acid (ChA), the most representative component of the polyphenolic fraction of artichoke, had no prominent effects on the cell death rate of MDA-MB231 cells. The addition of AEs to the cells, rather than ChA, triggered apoptosis via a mitochondrial and a death-receptor pathway, as shown by the activation of caspase-9 and caspase-8, respectively. Furthermore, an increase of the Bax:Bcl2 ratio and up-regulation of cyclin-dependent kinase inhibitor, p21(WAF1), crucial apoptotic players, were documented. According to our data on activation of caspase-9, a loss of mitochondrial transmembrane potential (Ψ(m)) was shown. Cell motility and invasion capabilities were remarkably inhibited by AEs-treatment in highly invasive MDA-MB231 cells. In addition, a significant decrease of proteolytic activity of metalloproteinase-2 protein (MMP-2), involved in degrading components of the extracellular matrix, was detected. Our findings indicate that AEs reduced cell viability, inhibited cell growth, triggered apoptotic mechanisms, and showed inhibitory properties against the invasive behavior of MDA-MB231 cancer cell line. Altogether, these data indicate the potential chemopreventive activity of artichoke polyphenolic extracts.

Verbascosides from olive mill waste water: assessment of their bioaccessibility and intestinal uptake using an in vitro digestion/Caco-2 model system.

Olive mill wastewater (OMWW) is an agricultural waste material produced in high quantities in the Mediterranean basin. OMWW may be an inexpensive source of health promoting phytochemicals with potential economic value including many low molecular weight compounds such as verbascosides. While promising as antioxidants in vitro, little information is available on the potential absorption of verbascosides by humans. The main objective of the present study was to characterize the verbascoside content and potential for their bioavailability from a partially purified phenolic fraction (IP) of OMWW. The IP was obtained after ultrafiltration step at 5000 Dalton and gel filtration low-pressure chromatography (LH20) of OMWW. RP-HPLC analysis identified several soluble phenolics compounds including verbascoside and isoverbascoside as major components of OMWW fractions. The potential for bioavailability of these polyphenols was estimated by using both in vitro digestion and Caco-2 human intestinal cell models. In vitro digestive recoveries (bioaccessibility) were found to be 35.5%± 0.55% for verbascoside and 9.2% ± 0.94% for isoverbascoside highlighting potential sensitivity of these phenolics to gastric and small intestinal digestive conditions. Accumulation of verbascosides by highly differentiated Caco-2 monolayers was linear between 10 and 100 µM of verbascoside and isoverbascoside from IP extract. Uptake of verbascoside and isoverbascoside was rapid with peak accumulation occurring after 30 min with total accumulation efficiency of 0.1% and 0.2% providing intracellular levels of 130 and 80 pmol/mg cell protein for verbascoside and isoverbascoside, respectively. Combined, these data suggest that verbascosides present in OMWW are bioaccessible and provides a rationale for subsequent in vivo studies on the bioavailability and bioactivity of OMWW components.

Biological activity of high molecular weight phenolics from olive mill wastewater.

Olive oil production generates large amounts of recalcitrant compounds, the olive oil mill wastewater (OMWW), which represent one of the most contaminating effluents among those produced by the agrofood industries. Nowadays, this view has changed to one that recognizes the waste as a low-cost starting material rich in bioactive compounds, particularly biophenols, that can be extracted and applied as natural antioxidants for the food and pharmaceutical industries. The data reported in this paper indicate that the OMWW extracts, besides low molecular weight antioxidant phenolics such as tyrosol and hydroxytyrosol, also contain phenolics with a molecular weight in the range of 600-5000 Da, which exhibit efficient scavenging activities against hydroxyl and peroxyl radicals. This group of phenolics includes, besides verbascoside, isoverbascoside, and an oxidized form of verbascoside, a number of higher molecular weight phenolics arising from oxidative polymerization of hydroxytyrosol and caffeic acid. Overall, these higher molecular weight phenolics prove to be, in some in vitro tests, more efficient scavengers of hydrophilic hydroxyl radicals than hydroxytyrosol, which could be used for industrial applications as natural nontoxic antioxidants.