Maurizio Masci

New trends in the seafood market. Sutchi catfish (Pangasius hypophthalmus) fillets from Vietnam: Nutritional quality and safety aspects

Sutchi catfish (Pangasius hypophthalmus) produced in the freshwater basins of Vietnam, available on the Italian market as frozen or thawed fillets, were studied for their nutritional quality and safety aspects. Proximate composition, mineral content, fatty acid profile, unsaponifiable components of the lipid fraction and drip loss during thawing at 5°C were determined on the fillets. Fillets were characterised by high moisture levels (80-85%) and low protein (12.6-15.6%) and lipid (1.1-3.0%) contents. Total lipids were characterised by low cholesterol levels (21-39mg/100g), high percentages of saturated fatty acids (41.1-47.8% of total fatty acid) and low percentages of polyunsaturated fatty acids (12.5-18.8% of total fatty acids), which were mainly represented by linoleic acid (44-59% of total polyunsaturated fatty acids). The mineral composition was characterised by a high sodium content (222-594mg/100g), probably partially due to the sodium tripolyphosphate (E 451) used to retain moisture. As regards safety aspects, the quality of the samples analysed was good, with low residue levels of mercury, organochlorine pesticides and polychlorinated biphenyls.

Organochlorine pesticide residues: an extensive monitoring of Italian fishery and aquaculture.

A sampling campaign from 21 sites in Italy was carried out to investigate the presence of organochlorine pesticide residues in different fish species. Samples came from marine fishery and either from sea- or freshwater aquaculture. Fish feed used in some fish farms were also analyzed. Pesticides studied belong to Persistent Organic Pollutants widely used in the past such as DDT, chlordane, heptachlor, and others. To ensure good quality results and proper data validation the main existing guidelines in the field were applied. The instrumental technique was a Dual column-Dual detector Gas Chromatography (GC-ECD and Ion Trap GC-MS) which allowed that complementary data on the same sample were acquired. Results for fishery showed a wide range of concentrations depending from the area and species examined. DDT, the major OC pesticide detected, varied from 0.02 to 130.03 ng g(-1) edible portion. As regards the products of aquaculture we observed slightly lower average levels of pollutants in a more narrow range of concentration: this is probably due to fish feed used as shown by some measures performed in the present study. Organochlorine pesticide residues were detected in all samples examined but they were generally well below the existing tolerance or action levels. Also the estimated daily intakes are well below than those recommended by WHO. This is a good indication about OCPs in the areas investigated but some further considerations on fish safety must be taken into account. An example on how fishes may act as bioindicators is reported.

Characterization of volatiles and identification of odor-active compounds of rocket leaves

The volatile profile of crushed rocket leaves (Eruca sativa and Diplotaxis tenuifolia) was investigated by applying Headspace Solid-Phase MicroExtraction (HS-SPME), combined with GC-MS, to an aqueous extract obtained by homogenization of rocket leaves, and stabilized by addition of CaCl2. A detailed picture of volatile products of the lipoxygenase pathway (mainly C6-aldehydes) and of glucosinolate hydrolysis (mainly isothiocyanates), and their dynamics of formation after tissue disruption was given. Odor-active compounds of leaves were characterized by GC-Olfactometry (GC-O) and Aroma Extract Dilution Analysis (AEDA): volatile isolates obtained by HS-SPME from an aqueous extract and by Stir-Bar Sorptive Extraction (SBSE) from an ethanolic extract were analyzed. The most potent odor-active compounds fully or tentatively identified were (Z)- and (E)-3-hexenal, (Z)-1,5-octadien-3-one, responsible for green olfactory notes, along with 4-mercaptobutyl and 4-(methylthio)butyl isothiocyanate, associated with typical rocket and radish aroma. Relatively high odor potency was observed for 1-octen-3-one, (E)-2-octenal and 1-penten-3-one.

Non-dioxin-like PCBs: a survey on fishery and aquaculture from the Mediterranean area

ABSTRACT A sampling campaign from 21 sites in Italy was conducted: 15 species from fishery and three species from aquaculture, for a total of 40 determinations, were considered. A careful sample preparation preceded the instrumental analysis that was carried out by means of GC–ECD and GC–MS. Good laboratory practice was achieved by the participation in proficiency tests, by the use of certified reference materials and by applying other directives recommended by international organisations. Concentrations measured in this work were compared with a TDI proposed by some international bodies: for a person weighing 70 kg one-third of the samples from fishery, when consumed, lead to exceed this TDI if the average fish daily consumption per capita is considered. Based on the data obtained here some hypotheses on environmental spreading and influence of PCBs on human health are made. Some suggestions about the preparation of fish for consumption are also given.