INFLUENCE OF NICOTINE AND DIPHENYLAMINE ON THE CAROTENOID COMPOSITION OF RHODOTORULA STRAINS

In order to obtain commercially interesting carotenoid profiles, the effect of supplementation with diphenylamine (DPA) and nicotine in the culture media of Rhodotorula rubra and Rhodotorula glutinis was studied. Fermentation experiments were carried out in flasks. The carotenoids were extracted with ethyl acetate by physical disruption, and analyzed by high‐performance liquid chromatography using a reversed‐phase column. At subinhibitory levels, both the inhibitors showed no effect on yeast growth for the two strains. Only R. rubra produced more carotenoids when 5 μmol of DPA was added to the broth, 155.8 μg/g of dry weight. For both strains, supplementation with 5 μmol DPA caused a significant reduction in the torularhodin/torulene ratio, from 1.5 to 0.5 for R. rubra, and from 0.8 to 0.5 for R. glutinis. With 10 μmol of this inhibitor, an accumulation of β‐carotene occurred from 13 to 47% in R. rubra, and from 36 to 43% in R. glutinis. Supplementation with nicotine resulted in the selective biosynthesis of lycopene (up to 93.8 μg/g) and the formation of a minor carotenoid, tentatively identified as 3,4‐didehydrolycopene, not previously related to Rhodotorula spp.     

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.     

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.

     

EFFECT OF SODIUM LAURYL SULFATE IN SOLUBILIZING PROTEIN FOR TRYPTOPHAN DETERMINATION

The solubilization of proteins in corn and sorghum, using sodium lauryl sulfate (NaLS) in a basic medium, was used for tryptophan determination. The experimental design evaluated different levels of sodium lauryl sulfate and sodium hydroxide, at various temperatures and times. Prior to treatment, the samples were dried, ground and defatted. These were hydrolyzed and tryptophan was quantified spectrophotometrically (λ_max= 565 nm). Casein was used as control and DL-tryptophan was used for generating the standard curve according to Beer's Law. From the results obtained, it was possible to conclude that sodium lauryl sulfate was very effective in solubilizing corn and sorghum protein for subsequent tryptophan determination.     

NATURAL LANGUAGE GENERATION AND HYPERTEXT ACCESS

Abstract

An innovative framework is presented that responds to the needs of a user that may want to have punctual personalized information integrated with the possibility of accessing standard browsable information through the same generated text. An implemented system is illustrated for generating natural language texts immersed in a hypermedia network. The architecture of the system and the specific solution given to the various components and their integration are described: the strategic component and its relation to the knowledge representation and to the user model, the tactical component and its connection to the strategic one, and the hypertext manager that accomodates the new linked text. Throughout the article explicit reference is made to the implementation solutions adopted and to examples relative to the experimentation of the work as part of the ALFRESCO interactive system.     

Surface Science Approach to Modeling Supported Catalysts

Nanoscale structural information underlies research aimed at fabricating catalysts in a more controlled way. Surface science methods can provide that information, but the complexity of heterogeneous systems in general hinders the application of these methods to their full potential. In the last decades, a solution to this problem has been found in the use of model systems, ranging from well-defined single crystals of the supported phase to films or particles of that phase on flat or spherical model supports. In this paper, we review the literature on the latter model systems, that is, particles on a model support. Attention is payed to both preparation and use of such model systems.     

Implementing block ciphering algorithms in hardware

Many ciphering algorithms map efficiently into hardware, giving encryption with very high throughput. Hardware designs are presented for two secretkey block ciphers, Blowfish and REDOC III. Pipelined systems using arrays of programmable logic and RAM offer encryption rates of 1032 Mbit/s and 1640 Mbit/s, respectively.     

Supercritical CO2 Extraction of Carotene and Lutein from Leaf Protein Concentrates

Supercritical fluid carbon dioxide was used to extract carotene and lutein from leaf protein concentrate (LPC). Extractions were performed using pressures of 10-70 MPa at 40°C and CO₂ flow rates of 5-6 L/min. Over 90% of the carotene contained in LPC was removed at extraction pressures in excess of 30 MPa. Removal of lutein from LPC required higher extraction pressures (70 MPa) and gas volumes to attain a 70% recovery level. Experimental results were rationalized with the aid of solubility parameter theory. The described process offers the possibility of obtaining a selective extraction of natural colorants, free of solvent residuals, which can be used as food dyes.