Syrah grape skin valorisation using ultrasound-assisted extraction: Phenolic compounds recovery,antioxidant capacity and phenolic profile

The influence of ultrasound power (1000–3000 W/L), citric acid concentration (0–3%) and solid:liquid ratio (1:5–1:15) on the phenolic compounds recovery and antioxidant capacity of Syrah grape skin extracts were evaluated. Total phenolic compounds varied from 6485 to 11732 mg gallic acid/100 g and monomeric anthocyanin content from 453 to 685 mg malvidin-3-glucoside/100 g. The antioxidant capacity measured by ORAC and ABTS methods ranged from 230 to 516 μmol Trolox/g and from 442 to 939 μmol Trolox/g, respectively. The most suitable conditions chosen for extraction, within the studied ranges, were 3000 W/L of power, 2.5% citric acid and solid:liquid ratio of 1:15. The extraction yield was satisfactory, with a recovery of 59% of the quantified phenolic compounds, with only 3 min of processing. Ultrasound was considered a suitable method as compared to the conventional extraction, improving the extraction of phenolic acids and facilitating their release.     

Polychlorinated biphenyls and organochlorine pesticides in seafood from the Gulf of Naples (Italy)

Seven target polychlorinated biphenyls (PCBs; IUPAC nos. 28, 52, 101, 118, 138, 153, and 180) and the organochlorine pesticides (OCPs) hexachlorobenzene (HCB) and dichlorodiphenyltrichloroethane (DDT) and its related metabolites (p,p'-DDT, p,p'-DDE, and p,p'-DDD) were quantified in edible tissues from seven marine species (European hake, red mullet, blue whiting, Atlantic mackerel, blue and red shrimp, European flying squid, and Mediterranean mussel) from the Gulf of Naples in the southern Tyrrhenian Sea (Italy). PCBs 118, 138, and 153 were the dominant congeners in all the species examined. The concentrations of all PCBs (from not detectable to 15,427 ng g(-1) fat weight) exceeded those of all the DDTs (from not detectable to 1,769 ng g(-1) fat weight) and HCB (not detectable to 150.60 ng g(-1) fat weight) in the samples analyzed. The OCP concentrations were below the maximum residue limits established for fish and aquatic products by the Decreto Ministerale 13 May 2005 in all the samples analyzed; therefore the OCPs in the southern Tyrrhenian Sea species are unlikely to be a significant health hazard. Conversely, the mean concentrations of PCBs exceeded (greatly in some cases) the current limits (200 ng(-1) fat weight) set by the European Union for terrestrial foods. Although the manufacture and use of PCBs are banned or highly restricted, these compounds still are important persistent chemical contaminants in the Gulf of Naples.     

Induction of Oxidative Stress by Sunflower Phytotoxins in Germinating Mustard Seeds

The aim of this study was to investigate the phytotoxic effect of sunflower on physiological and biochemical processes during germination of mustard seeds (Sinapis alba L. cv. Nakielska). To exclude the involvement of osmotic stress in seed reaction to phytotoxic compounds, we compared the effect of 10% (w/v) water extract from sunflower (Helianthus annuus L. cv. Ogrodowy) leaves and 28.4% (w/v) polyethylene glycol (PEG) 8000 solution characterized by an equal Ψ = −1 MPa. We evaluated (1) the amount of hydrogen peroxide (H₂O₂); (2) activities of antioxidant enzymes: superoxide dismutase, catalase, and glutathione reductase; (3) membrane permeability; and (4) level of malondialdehyde (MDA). Both, sunflower compounds and PEG solutions inhibited mustard seed germination, but only phytotoxins caused an increase in the cell membrane permeability, MDA level, H₂O₂ concentration, and alterations in activities of antioxidant enzymes. Our results demonstrate that despite the activation of the antioxidant system by sunflower phytotoxins, reactive oxygen species accumulation caused cellular damage, which resulted in the decrease of germinability and gradual loss of seed vigor. It seems that the negative effect of sunflower on germination of mustard seeds is mostly because of its toxicity and not to its contribution to osmotic potential.     

Species,roasting degree and decaffeination influence the antibacterial activity of coffee against Streptococcus mutans

Coffee beverage has been associated with antibacterial activity against Streptococcus mutans, a cariogenic bacterium. This study aimed at identifying natural compounds in coffee that contribute to such activity and investigate the influence of species, roasting and decaffeination on it. Coffee chemical compounds and aqueous extracts of green and roasted regular and decaffeinated Coffea arabica and Coffea canephora beans were tested. MIC, biofilm inhibition and biofilm reduction results were correlated with the concentration of coffee compounds in the extracts. 5-Caffeoylquinic acid, trigonelline and caffeic acid solutions showed bacteriostatic activity (MIC = 0.8 mg/mL). Lighter and regular extracts showed higher inhibitory activity than darker and decaffeinated extracts, with an inverse correlation between bacterial colony-forming units and roasting degree. Only regular C. canephora extracts showed biofilm formation inhibition. The joint effect of chlorogenic acids, trigonelline and caffeine or other compounds removed by decaffeination seems to be one of the causes for coffee antibacterial activity against S. mutans.