Evolution of free amino acids during ripening of Caciocavallo cheeses made with different milks

The evolution of free amino acids (FAA) in Caciocavallo cheeses, made with cow milk (CC) and cow milk mixed with ewe (CE) and goat (CG) milk, was studied throughout ripening. In all Caciocavallo cheeses produced, the total free amino acid (TFAA) content increased during ripening. In general, the highest TFAA content was found in cow cheeses, and the lowest in CG cheeses, whereas CE cheeses ranged over an intermediate level. In all the analyzed samples, during ripening, the content of the individual FAA increased with the exception of arginine. Tyrosine and histidine were found only in CE samples from the middle to the end of ripening. The major FAA found throughout the whole ripening period, in all types of cheese, were leucine, phenylalanine, lysine, valine, asparagine, γ-aminobutyric acid, and ornithine. The TFAA and several AA showed significant differences in ripening time, whereas tyrosine and histidine showed significant differences in kinds of milk.     

Polyphenolic pattern and in vitro cardioprotective properties of typical red wines from vineyards cultivated in Scafati (Salerno,Italy)

Wines are the subject of increasing numbers of investigations owing to the pharmaceutical usefulness of grape phytochemicals. The aim of the present work was to hypothesize the use of lyophilised red wines for the formulation of food supplements potentially useful against both physiological and induced cardiac oxidative stress. Cardiac derived H9C2 myocytes were incubated with increasing doses (0.01–1 μg) of lyophilised Aglianico wine (lioAW). Experiments showed an appreciable direct radical scavenging activity at a maximum lioAW dose of 0.03 μg that made the caspase-3 activity decrease by about 41%. Cardiac cells were exposed to 1 μM doxorubicin and its combination with different doses of lioAW. Maximum lioAW aliquot of 0.03 μg seemed to effectively contrast the induced oxidant injury decreasing the reactive oxygen species (ROSs) levels by about 38%and depressing the caspase-3 activity by about 63%. In both assays, pro-oxidant effects at higher lioAW concentrations were detected.     

Yeast dynamics during spontaneous wine fermentation of the Catalanesca grape

Although the use of starter cultures in winemaking has improved the reproducibility and predictability of wine quality, the main drawback to this practice is the lack of the typical traits of wines produced by spontaneous fermentation. In this study, we identified for the first time the yeast population occurring during spontaneous fermentation of the Catalanesca white grape, a variety from Campania (Italy). Yeasts were identified using molecular tools: PCR-DGGE and partial sequence analysis of the 26S rRNA gene from isolates. Eighteen different species belonging to 11 different genera were identified. Hanseniaspora spp., Issatchenkia spp. and Candida spp. were the dominant yeasts during the early stages of fermentation, while the middle and end phases were dominated by Saccharomyces cerevisiae. Four species of Issatchenkia spp., rarely isolated from wine fermentation, were found in this study accounting for the 33.5% of the total isolates. The RAPD-PCR screening of the isolates followed by partial rRNA gene sequencing proved to be a very effective approach to first differentiate the isolates and then identify yeast species involved in a wine making procedure. The results show very high yeast diversity in this natural wine fermentation and also highlight the possibility of considering interesting autochthonous strains for starter selection.     

Evaluation of microbial diversity during the manufacture of Fior di Latte di Agerola, a traditional raw milk pasta-filata cheese of the Naples area

Microbial diversity of the raw milk for the production of Fior di Latte di Agerola and its changes during cheesemaking were studied. Viable counts showed that at the end of curd ripening, loads of lactic acid bacteria, both mesophilic and thermophilic rods and cocci, higher than those commonly evidenced in similar cheeses produced by using natural or commercial starters, were detected. Identification of 272 isolates, supported by molecular diagnostic aids, evidenced representative cultures of a high number of bacterial taxa of interest as participating in the process, although most of the isolates belonged to Lactococcus lactis and Lactobacillus helveticus species. RAPD-PCR and REA-PFGE biotyping were performed for the isolates of the above species and it was shown that most of the strains isolated from the raw milk occurred during the whole cheesemaking process, and an active role of these strains in the fermentation was supposed. The results offer further proof of the importance of the raw milk as source of technologically interesting strains of lactic acid bacteria capable of driving the fermentation of traditional cheeses.     

Adsorption with axial diffusion in shallow beds

Approach to constant pattern behavior and breakthrough behavior are analyzed for adsorption in fixed beds with axial diffusion. Local equilibrium between fluid and solid phases is assumed, with concentrations related by favorable Langmuir and Freundlich isotherms. Results are presented as midheight slopes of internal and actual breakthrough curves and as breadths of actual breakthrough curves. The solutions merge smoothly with asymptotic limits appropriate for deep beds and results obtained here for very short beds. It is shown that breakthrough curves are sharper than corresponding internal breakthrough curves for beds of any length, with the difference being even more pronounced in shallow beds than in deep beds. The principal factor that determines whether or not a breakthrough curve differs significantly from the corresponding internal breakthrough curve, regardless of whether the bed is long or short or the isotherm very favorable or linear, is the breadth of the adsorption wave near the bed outlet.     

Salt effect on gel permeation chromatography of partially charged polymers

The effect of the addition of 0.1M LiBr to dimethylformamide (DMF) solutions of charged and uncharged polymers has been studied by GPC and [η] measurements. LiBr has a salting-out effect on polyacrylonitrile (with (PAN-S) and without (PAN) sulfonate sulfur), polystyrene (PS), and poly(vinyl acetate) (PVAc), which is seen by a decrease in [η] and an increase in the GPC retention time. The increase in retention time is, however, abnormally high for charged polymers. Association in PAN and PAN-S solutions in DMF can explain the experimental observations.     

Gas holdup and mass transfer in solid suspended bubble columns in presence of structured packings

Electrochemical gas absorption or biotechnical purification processes using structured packing as electrode or as biological support, respectively, may operate in bubble columns in presence of suspended solids. In both systems the knowledge of mass transfer rates from the liquid to the packing is important for the design of equipment. In the present investigation, the fluid dynamic behavior of a simple bubble column and a bubble column containing small size particles, both in presence of structured packing, was studied. Furthermore, mass transfer coefficients between the liquid and the structured packing were obtained by the electrochemical method. The influence of physical properties of the liquid phase, gas flow rate, kind and concentration of the suspended particles on both gas holdup and mass transfer was investigated. Correlations of the experimental data of mass transfer using dimensionless groups were derived and compared to previous correlations. Similarity with a heat transfer expression already used in two-phase systems was found.     

Global stabilization of the spinning top with mass imbalance

We consider the stabilization of a top with known imbalance to the sleeping motion. We first define the sleeping motion and show that it is a solution of the equations of motion of a balanced top. In the general case where the top is unbalanced, we derive two families of control laws that globally asymptotically stabilize a top with known imbalance to the sleeping motion using torque actuators. The input torque is produced by two body-fixed torque actuators in one case, and is confined to the inertial "XY-plane in the other. The control-design strategy is based on Hamilton-Jacobi-Bellman theory with zero dynamics. The result is global in the sense that the spinning top can be stabilized to the sleeping motion regardless of spin rate, and from an arbitrary initial motion that has a coning angle of up to 90^°