Effect of somatic cell counts on lipolysis,proteolysis and apparent viscosity of UHT milk during storage

In this work, lipolysis, proteolysis and viscosity of ultra‐high temperature (UHT) milk containing different somatic cell counts (SCC) were investigated. UHT milks were analysed on days 8, 30, 60, 90 and 120 of storage. Lipolysis as measured by free fatty acids increase, casein degradation and viscosity of UHT milk were not affected by SCC but increased during storage. A negative relationship was observed between SCC and casein as a percentage of true protein on the 120th day of storage, hence indicating that high SCC increases the proteolysis of UHT milk by the end of its shelf life.     

DIFFERENTIATION OF CURED COOKED HAMS BY PHYSICO-CHEMICAL PROPERTIES AND CHEMOMETRICS

Comparison of physico-chemical and compositional traits was carried out on cooked hams. Deboned fresh pig thighs of three different origins were divided into three batches: 200 pig thighs from the Italian market, H1; 200 from The Netherlands, H2; and 200 from Denmark, H3. Boneless pig thighs were processed under commercial guidelines for production of cooked hams, using brine at 25% level of injection. After processing, 12 cooked hams from each batch were sampled randomly and analyzed for proximate and fatty acid composition. Color measurement was performed on the muscles: biceps femoris, semimembranosus, and semitendinosus. H1 hams showed a higher weight loss and a lower technological yield compared to H2 and H3 hams. Analysis of variance on compositional data showed that H1 hams had a lower moisture/protein ratio, a higher fat content, a lower percentage of α -linolenic, eicosapentaenoic and docosahexaenoic acid, and a higher percentage of myristic and palmitic acids when compared to H2 and H3 hams ( P   <  0.05). Analysis of color of the three muscles demonstrated that hams from the H1 group had the highest a * values. The application of linear discriminant analysis demonstrated that the use of only four variables allowed to correctly discriminate among groups of cooked hams.

PRACTICAL APPLICATIONS

The following are the practical applications of this research. The comparison of physico-chemical and compositional traits were carried out on cooked hams. Pig thighs of different origin were processed under commercial guidelines. The physicochemical parameters of cooked hams were defined and showed some differences characterizing the products.     

Wigner equation of motion for time-dependent potentials

The equation of motion is obtained for the Wigner distribution for time-dependent potentials. It is shown that one cannot obtain an equation of motion for the standard Wigner distribution but one can do so for the fourdimensional distribution of the variables position, momentum, time, and frequency. Three forms are given and it is shown that for time-independent potentials the new form reduces to the equations originally obtained by Wigner and Moyal.     

PRELIMINARY EVALUATION OF THE APPLICATION OF THE FTIR SPECTROSCOPY TO CONTROL THE GEOGRAPHIC ORIGIN AND QUALITY OF VIRGIN OLIVE OILS

ABSTRACT

A rapid Fourier transform infrared (FTIR) attenuated total reflectance spectroscopic method was applied to determine qualitative parameters such as free fatty acid (FFA) content and the peroxide value (POV) in virgin olive oils. Calibration models were constructed using partial least squares regression on a large number of virgin olive oil samples. The best results (R² = 0.955, root mean square error in cross validation [RMSECV] = 0.15) to evaluate FFA content expressed in oleic acid % (w/w) were obtained considering a calibration range from 0.2 to 9.2% of FFA relative to 190 samples. For POV determination, the result obtained, built on 80 olive oil samples with a calibration range from 11.1 to 49.7 meq O₂/kg of oil, was not satisfactory (R² = 0.855, RMSECV = 3.96). We also investigated the capability of FTIR spectroscopy, in combination with multivariate analysis, to distinguish virgin olive oils based on geographic origin. The spectra of 84 monovarietal virgin olive oil samples from eight Italian regions were collected and elaborated by principal component analysis (PCA), considering the fingerprint region. The results were satisfactory and could successfully discriminate the majority of samples coming from the Emilia Romagna, Sardinian and Sicilian regions. Moreover, the explained variance from this PCA was higher than 96%.

PRACTICAL APPLICATIONS

The verification of the declared origin or the determination of the origin of an unidentified virgin olive oil is a challenging problem. In this work, we have studied the applicability of Fourier transform infrared coupled with multivariate statistical analysis to discriminate the geographic origin of virgin olive oil samples from different Italian regions.

     

Chlorophyll Stability During Continuous Aseptic Processing and Storage

Spinach puree was aseptically processed and packaged at four time-temperature treatments (19.2 and 5.3 sec @ 142°C; 19.2 and 12.2 sec @ 137°C). Samples processed at 142°C for 5.3 sec retained 68% of total chlorophyll compared to blanched samples while all chlorophylls were degraded in retorted product. The rate of chlorophyll b degradation and pheophytin b formation during storage in flexible containers at 4, 25, and 40°C fit a first order kinetic model. Apparent activation energies during storage for each time-temperature treatment ranged between 11.1 and 14.3 kcal/mol. Analyses of degradation products indicated oxidation during storage was not a dominant factor in chlorophyll conversion and color loss.     

Long term immunological perturbations post DAA therapy in chronic HCV/HIV co-infected patients

Direct-acting antiviral (DAA) therapies are efficacious for the achievement of sustained virologic response (SVR) in almost all treated hepatitis C virus (HCV)-infected patients. However, the impacts of HCV eradication on immune function and chronic immune activation in the long-term remain controversial and limited, especially in patients co-infected with human immunodeficiency virus (HIV). Indeed, although restoration of many immune responses clearly can be observed, several features of immune perturbations persist over time after HCV clearance. Understanding the degree and reasons of the partial recovery of the immune system in chronic HCV/HIV co-infection after HCV elimination is pivotal to avoid disease progression and possible long-term clinical outcomes in cured patients, as well as contributing to the development of immunotherapy drug design.     

Application of the Wigner distribution to nonlinear systems

A new way to study nonlinear oscillations is presented, based on Time—Frequency Analysis, a technique that allows the representation and study of the instantaneous spectral content of a signal. The investigation of nonlinear oscillations is an interesting subject in many areas of physics and engineering, especially in nonlinear optics where this phenomenon arises directly from the interaction of electromagnetic waves and matter. Here it is shown how Time—Frequency Analysis can clarify the nature of a free nonlinear oscillation, which is proven to have a peculiar yet physically reasonable instantaneous spectrum.     

IMPERFECT SQUEEZING FLOW VISCOSIMETRY OF SELECTED TOMATO PRODUCTS1

The rheological properties of different brands of commercial tomato paste, sauce, puree and ketchup were estimated by imperfect squeezing flow viscosimetry using a wide plate and a shallow container. The tests were performed with polished and grooved surfaces. In both, slip was prominent to such an extent that the equations for lubricated squeezing flow had to be used for the calculation of rheological parameters. Despite its crudeness, the procedure was sensitive enough to consistently monitor rheological differences between commercial products of different brands in terms of the apparent stress at a given specimen height, the consistency, K , and flow index, n, of the pseudoplastic liquid constitutive equation, and the apparent biaxial elongational viscosity, μ_b and its strain rate dependency. In tomato paste, the flow behavior index was approximately the same in all the brands (n ～ 0.5), and the values of K and μ_b had a linear relationship. Residual forces after relaxation provided an additional textural measure related to the yield stress. Differences between products of different brands could be consistently monitored regardless of whether the test was performed at a fixed specimen height or a preset initial force.