Distribution of polychlorinated biphenyls, polycyclic aromatic hydrocarbons and organochlorine pesticides in marine organisms from the coastal areas of the southern Shandong Peninsula, China | Author : Weihong Zhao | Abstract | Full Text | Abstract :The concentration and distribution of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in organisms from the coastal area of southern Shandong Peninsula were investigated. Concentrations of PCBs, PAHs and OCPs were highest in fish samples owing to their high lipid content. For PCBs, fish samples possessed high amounts of low-chlorinated biphenyls, while mollusk and shrimp samples had more highly-chlorinated biphenyls. All 16 PAHs were detected in marine organisms and the content of high molecular weight PAHs increased gradually from fish to mollusk, and to shrimp. Four isomers of HCHs were detected in marine organisms with recoveries higher than 90%. DDTs in marine organisms have been biodegradated mostly with little parent DDT input. Pollution profiles in different marine organisms were different due to differences water solubility. Their biological habits, habitats and related physiological characteristics were important factors describing these pollution profiles. |
| The challenge of monitoring the hydrolysis of foods lipids during gastrointestinal digestion | Author : María D. Guillén | Abstract | Full Text | Abstract :During the last decade obtaining further knowledge on lipid digestion has become a challenging task in the field of Food Science and Nutrition research. However, the great complexity of this process requires the use of sound, accurate and simple analytical techniques which are able to provide as much information as possible; only thus can a global view and therefore a better understanding of the ongoing process be obtained. This review tackles the advantages and drawbacks of the different methodologies currently employed for this purpose, focusing on a new approach, recently developed and based on Proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. This new methodological approach not only provides a great deal of information in a simple, rapid and accurate way, but also overcomes many of the disadvantages of the techniques employed to date. In this sense, 1H NMR can be considered a very promising alternative for research on lipid digestion, contributing to shed more light on the complex digestion process of lipids and the factors that may affect it.
Keywords: lipolysis, digestion, NMR spectroscopy, pH-stat titration, chromatography. |
| Near infrared reflectance spectroscopy of pasticceria foodstuff as protein content predicting method | Author : Fiorella Sarubbi | Abstract | Full Text | Abstract :Background: The authors evaluated the potential of NIR spectroscopy for the analysis of protein of pasticceria food, and it have analyzed 120 samples.
Methods: Protein content reference was obtained by standard lab procedure. The authors used spectra and reference data, partial least squares regression analysis that was applied to calculate a NIR method model (n=120), divided into calibration (n=84) and validation (n=36), to predict protein content in fed.
Results: The study shows that using NIR technique spectra and using PLS regression, a model could be developed having a root mean square standard error of performance of R2 value of 0.81. The regression coef?cients show that analytically useful absorptions for the original PLS model are between 4000 and 4500nm.
Conclusion: a NIR model was developed for the prediction of protein in pasticceria products, which is suf?ciently accurate for screening samples. Screening can be accomplished rapidly without the use of chemicals.
Keywords: NIR; food; protein content. |
| Replacement meal to treat overweight patients | Author : Roberto Volpe | Abstract | Full Text | Abstract :Overweight and obesity are cardiovascular risk factors. Qualitative and quantitative diet and active lifestyle are the best way to lose weight. In our study we have assessed the effectiveness and tolerability of a soluble powder rich in fibers and at low glycemic index used as replacement meal (for a total calorie intake ranging from a minimum of about 130 kcal to a maximum of 260 kcal) in 50 overweight subjects of the outpatient clinic of the Italian National Research Council (CNR) of Rome already in treatment with a low-fat low-carbohydrates qualitative diet. The study was a parallel, prospective trial of two randomized sample groups, “intervention” (25 subjects) versus “control”(25 subjects). After 8 weeks, the treatment based on the replacement meal has improved the results obtained through the qualitative diet alone: 18/25, versus only 5/25 in the control group, became ranged within normal weight. The subjects in the intervention group have improved also their cardio-metabolic parameters and consequently have reached a high statistically significant reduction in estimated cardiovascular risk at 10 years. |
| A colorimetric assay using tetrazolium salts with an electron mediator to evaluate yeast growth in opaque dispersed systems | Author : Carmen Adriana Campos | Abstract | Full Text | Abstract :Background: traditional microbiological enumeration techniques such as colony count are time consuming. Visual evaluation of turbidity growth lacks objectivity and precision. On the other hand, the accuracy of the spectrophotometric readings can be limited by media opacity and/or additives. In this context, colorimetric methods based on tetrazolium salts are an alternative to traditional methods due to their ability to generate endpoints based on color change. The objective of this study was to develop a colorimetric assay based on two different tetrazolium salts and an electron mediator in order to replace the conventional method of viable plate count or absorbance for microbial growth detection in opaque dispersed systems.
Methods: a colorimetric method to evaluate yeast growth in broth and opaque dispersed systems using two tetrazolium salts, 2,3,5-triphenyl-2H-tetrazolium chloride (TTC), 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) and an electron mediator, 2-methoxy-1,4-Naphthoquinone (MNQ) was developed. In addition, the minimum inhibitory concentrations against Zygosaccharomyces bailii for natamycin and lemongrass essential oil were determined by the proposed method and compared with those obtained using the conventional broth microdilution and plate count methods.
Results: showed that the mixture of INT/MNQ, was more effective than TTC/MNQ. In opaque structure systems, the later showed to be more sensitive than absorbance However, in broth it was as sensitivity as absorbance to detect yeast growth. Besides, the INT/MNQ reagent functioned adequately to determine the minimum inhibitory concentrations of antimicrobials in opaque structured systems.
Conclusions: These results demonstrated that the proposed method functioned adequately to determine the minimum inhibitory concentrations of antimicrobials in opaque structured systems showing an excellent agreement with the plate count method and the proposed technique allowed the evaluation of yeast growth with lower population levels than the ones required through absorbance readings. Moreover, this colorimetric method is easy to perform and less time consuming.
Keywords: antimicrobials, minimum inhibitory concentration, naphthoquinone, nontransparent media, redox technique, tetrazolium chloride. |
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