Simultaneous determination of melatonin and trans-resveratrol in wine by dispersive liquid-liquid microextraction followed by HPLC-FLD.

The discovery of melatonin (Mel) in wines triggered a new interest in the paradigm of health benefits and wine consumption, usually ascribed to trans-resveratrol (trans-RSV). In this context, a dispersive liquid-liquid microextraction for the analysis of Mel and trans-RSV in wines by LC-FLD was developed. A 26-1 factorial design was used to identify the significant variables (p < 0.05) and Central Composite Design was used to achieve the optimal conditions: 300 µL of chloroform (extracting solvent), 1500 µL of acetonitrile (disperser solvent) and 1500 mg of NaCl (ionic strength). Excellent linearity (R2 > 0.9999), repeatability (<3.55%), and accuracy (<7.18%) were obtained using a blank matrix and recoveries (>91.9%) using wines. The method was successfully applied to the analyses of Mel (0.63-7.44 ng mL-1) and trans-RSV (169-2616 ng mL-1) in different wine varieties. Comparison with literature point the overall advantages of the new method.

Table olives and health: a review.

Table olives, a product of olive tree (Olea europaea L.), is an important fermented product of the Mediterranean Diet. Agronomical factors, particularly the cultivar, the ripening stage and the processing method employed are the main factors influencing the nutritional and non-nutritional composition of table olives and their organoleptic properties. The important nutritional value of this product is due to its richness in monounsaturated fat (MUFA), mainly oleic acid, fibre and vitamin E together with the presence of several phytochemicals. Among these, hydroxytyrosol (HT) is the major phenolic compound present in all types of table olives. There is a scarcity of in vitro, in vivo and human studies of table olives. This review focused comprehensively on the nutrients and bioactive compound content as well as the health benefits assigned to table olives. The possible health benefits associated with their consumption are thought to be primarily related to effects of MUFA on cardiovascular health, the antioxidant (AO) capacity of vitamin E and its role in protecting the body from oxidative damage and the anti-inflammatory and AO activities of HT. The influence of multiple factors on composition of the end product and the potential innovation in the production of table olives through the reduction of its final salt content was also discussed.