S & TA & NU. Rivista di scienza e tecnologia degli alimenti e di nutrizione umana最新文献

The colorimetry of food has advanced during last years very much, due to the improving of the equipment and has solved several theoretical and practical problems for the food utilization. In the present paper are reviewed the procedures adopted and the results obtained for the objective evaluation of the colour of processed fruits and vegetables. These results have pointed out the importance of colorimetry in this field and outlined the future trends of the research.

The influence on liquid scintillation counting efficiency of internal standards toluene-14C, hexadecane-14C and ethanol-14C has been studied for low level-14C measuring of ethanol samples. Many biological and synthetic samples of ethanol have been counted: the best results are obtained with external standardisation on quenching calibration curve made with ethanol-14C. External standardisation on quenching calibration curve made with toluene-14C is preferable to internal standardisation with ethanol-14C. Hesadecane-14C as internal standard gives activities rather higher than true values.

The researches on the mode of action of vitamin D have shown that vitamin D3 in animals is not utilized as such but after Hydrosylation of carbon 25 in the liver and of carbon 1 in the kidney. 1alpha,25-dihdroxycholecalciferol (1alpha,25-(OH)2D3) is the active on two target organis the intestin and bones, acting as a steroid hormone. In the intestin it controls the syntesis of a specific calcium binding protein (CaPB) responsable for calcium absorption. At the bone level it act on the deposition of calcium salts, and whenever necessary on its mobilization. Therefore 1alpha,25(OH)2D3 is active part of the calcium homeostatic system in the organism together with specific hormones such as parathyroid hormone and calcitonin.

A analytical method to identify and quantitate residues of polychlorinated biphenyls, polychlorinated terphenyls, polychorinated naphtalenes and some chlorinated pesticides is described. These contaminants can be recovered from foods or other materials: a silicic acid coloumn chromatografic method previously developed is used to separate PCB's, PCT's, PCN's from organochlorinated pesticide residues. The PCB's, PCT's, PCN's residues identification and their subsequent quantitation can be achieved by conversion into well defined single perchloro-derivatives, viz decachlorobiphenyl, o.m.p. tetradecachloroterphenils and octachloronaftalene, detactable by GLC-EC. The reagnet of exhaustive chlorination of PCB's and PCT's residues is SbCl5, while the reagent used for the exhaustive chlorination of PCN's residues is SO2Cl2 with powdered anhydrous AlCl3 as a catalyst. The identity of perchloroderivatives obtained by chlorination of PCB's, PCT's, PCN's standard mixtures is confirmed on comparing their infrared spectra with the spectra of high purity standards.

Many people today, in agricolture, zootechny and animal feeding, operate with antibiotics and chemotherapeutics. Not all perhaps, know the inconveniences that the large and uncontrolled use of these substances may cause first of all the emergency of bacteria strains resistant to these drugs. We have devoted our attention particularly to the modalities of establishment of the phenomenon: to its incidence and variability in nature, to its transferability and, at least, to its biochemical aspects.

On the basis of the several studies recently published on the concentration of Hg and other heavy elements in seafish and especially tunafish a work as been carried out to determine the intake due to canned tunafish for the italian population. Instrumental activation analysis has been applied to tunafish canned samples avaible on the market in Rome. The following trace elements have been measured: Cr, Se, Hg, Cs, Fe, Zn, Co, Sb. The intake of Hg and other elements through the canned tuna foods have been evaluated on the basis of the production of such foods in Italy. The tunafish contribution to the total trace elements intakes has been determined by comparing the trace elements concentrations in the canned tunafish with those referred to diets that are representative for the italian population. The results obtained have demonstrated that the trace elements intake through the diet is not significantly influenced by the tunacanned foods intake.

The analysis of rot in two grape cultivars ("Moscato bianco" and "Favorita") has shown that the most effective gamma rays dose which pasteurizes fruit pulp with little or no damages is about 180-200 Kr. if administered divided into three fractions, the irradiated sample is less affected by infections (P = 0.01) then the 100 Kr or control samples. On the opposite, no difference between various doses could be detected when gamma rays are administered all at once.