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Biomedical subjects

O Pinho

Publications and source records attributed to O Pinho.

7 recordsLinked to original sources
PubMed2006

Casein breakdown in terrincho ovine cheese: comparison with bovine cheese and with bovine/ovine cheeses.

Terrincho cheese is an uncooked, pressed cheese made from raw whole ovine milk from the "Churra da Terra Quente" breed. It requires a minimum ripening time of 30 d. A detailed evaluation of the effect of ripening time on the breakdown of the casein fractions, along with the formation of major breakdown products of casein hydrolysis, was monitored by HPLC to contribute to a more complete characterization of this product. In 30-d-old cheeses, only 20% of alpha(S1)-casein remained intact; the beta-casein fraction was more resistant to hydrolysis. The ripening time of Terrincho cheese can be predicted using 2 variables of normalized peak areas of alpha(S1)-casein and alpha(S1)-I peptide, and a constant; the estimation error is 2.5 d. The pH 4.3-insoluble fraction of Terrincho and cheeses manufactured with bovine milk and with ovine milk combined with 2 levels of bovine milk (10 and 20%) revealed different chromatographic and electrophoretic profiles, especially the alpha(S1)-casein fraction. Similar proteolysis progress was observed, particularly in the percentage of casein fraction degradation. However, using both analytical methods, the detection of 10% bovine milk at 30 d of ripening was no longer possible as result of alpha(S1)-casein hydrolysis. The discriminate analysis applied to HPLC data indicated that at 30 d of ripening, differences between the casein fractions of Terrincho cheese and mixture cheeses were mainly from beta1-casein content. The function thus obtained was able to correctly classify all the samples according to cheese type. Using the descriptive sensory profile, Terrincho cheese at 30 d of ripening could be distinguished from bovine and mixture cheeses owing to its higher fracturability and adhesiveness and lower elasticity and hardness, which correlated with its lower total casein content.

Animals↗
PubMed2004

Chemical, physical, and sensorial characteristics of "Terrincho" ewe cheese: changes during ripening and intravarietal comparison.

The objectives of this study were to monitor the changes in chemical [moisture, acidity, pH, and water activity (a(w))] and physical (color and texture) parameters of "Terrincho" ewe cheese during 60 d of ripening, and to determine the correlations between the changes in instrumental texture and color parameters and the ripening time of the product. Intravarietal comparison of Terrincho ewe cheese from 5 different dairy plants was performed by evaluation of mechanical parameters from texture profile analysis (TPA) and color parameters in terms of CIELAB color space (L*, a*, and b*). In addition to mechanical and color tests, composition analyses and sensory tests were performed. The results were evaluated with statistical methods (single valued and multivariate analysis). During the first 20 d of ripening, an increase in hardness, fracturability, gumminess, chewiness, and yellowness occurred. Simultaneously, adhesiveness, resilience, L* (inside cheese, "i" and external "e"), and cohesiveness decreased. After 20 d of ripening hardness, fracturability, gumminess, and chewiness decreased and cohesiveness increased. The ripening time of Terrincho cheeses can be estimated with 6 variables: L* (external, e), L* (i), b* (inside cheese, i), hardness, a* (i), chewiness, and a constant. The estimation error was 4.2 d. Evaluation of composition, pH, texture profile analyses, color, and related sensory characteristics of Terrincho cheeses from 5 different dairy plants (with 30 d of ripening) revealed correlations between these parameters.

Analysis of Variance↗
PubMed2003

Solid-phase microextraction of volatile compounds in "Terrincho" ewe cheese. Comparison of different fibers.

Solid-phase microextraction coupled to gas chromatography-mass spectrometry (GC-MS) was applied to study the volatile compounds in "Terrincho" ewe cheese. Six types of fibers were tested and the main extraction parameters were studied. Carboxen-polydimethylsiloxane fiber 75 microm (CAR-PDMS) achieved the most complete profile of ewe cheese volatile compounds. The optimised conditions used for characterization of "Terrincho" ewe cheese were: sample vial equilibration at 20 degrees C for 20 min, followed by CAR-PDMS fiber exposure to the headspace above the sample for 30 min and finally thermal desorption of the adsorbed substances, in the injector port for GC-MS analysis. This technique was a useful tool for the differentiation of 11 "Terrincho" ewe cheeses, all taken from the same cheesemaking season with 30 days of ripening but from three different farmhouses, according to their volatile fraction. Results obtained were statistically treated by categorical principal component analysis. Subsequently, 49.15% of the variation in data was due to the first dimension (k = 12.7) and the second dimension (k = 8.88) accounted for 34.2% of the total information. Volatile profiles among samples indicated cheese group separation according to farmhouse of production.

Animals↗
PubMed2003

Congenital chylothorax: a case report.

A case of unilateral congenital hydrothorax diagnosed at 21 weeks and treated with a pleuro-amniotic shunt at 23 weeks' gestation is presented. The rapid production of pleural fluid led to the development of polyhydramnios which was treated with a selective Cox inhibitor. Due to worsening of the hydrothorax, a third thoracocentesis was performed at 30 weeks' gestation prior to a Cesarean section. The neonate responded well to mechanical ventilation, a thoracic drainer that was inserted between days 5 and 14, fluid and protein replacement and gradual transition from parenteral to intestinal nutrition. Early diagnosis of chylothorax should be treated by thoraco-amniotic drainage to prevent fetal pulmonary hypoplasia and congestive cardiac failure. Polyhydramnios is a complication of this therapy and may require treatment with a Cox inhibitor.

Adult↗
PubMed2003

Quantification of short-chain free fatty acids in "Terrincho" ewe cheese: intravarietal comparison.

Headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was employed for the quantification of volatile free fatty acids (FFA) in "Terrincho" ewe cheese. Solid-phase microextraction quantitative analysis was feasible under equilibrium situations as long as the conditions of agitation and the adsorption time were held constant. An excellent linear relationship between the amount of the adsorbed analyte and its initial concentration in the sample matrix was obtained when an adequate amount of sample was chosen. Thus, quantification was possible if biases due to competition or linear range excesses were controlled. Solid-phase microextraction sampling was carried out at 65 degrees C, and a fiber coated with an 85-micro/m polyacrylate film was chosen. After equilibration at 65 degrees C for 40 min, the fiber was exposed to the headspace above the sample for 20 min and then inserted into the gas chromatograph. The evolution of the volatile FFA during Terrincho ewe cheese ripening was analyzed for a 60-d period. An overall increase in FFA contents was verified up to 30 d of ripening. Between 30 and 45 d most FFA did not suffer significant changes. All FFA increased significantly by the 60-d ripening period. The excessive lipolysis observed at 60 d of ripening may result in the presence of off-flavors. Principal component analysis performed for intravarietal comparison of volatile FFA composition of 19 Terrincho cheeses, analyzed at 30 ripening days, enabled discrimination between cheeses produced at five different dairy plants.

Animals↗
PubMed2002

Solid-phase microextraction in combination with GC/MS for quantification of the major volatile free fatty acids in ewe cheese.

This work describes a method for quantification of the major free fatty acids of ewe cheese that contribute to its distinct and strongly marked flavor. A headspace SPME method in combination with GC/MS was used for the extraction, identification, and quantification of butanoic, hexanoic, octanoic and decanoic acids in ewe cheeses. The method used for sample preparation was simple. A fiber coated with 85-microm polyacrylate film was chosen to extract the free fatty acids. To perform a reliable quantification, several factors were taken into consideration for reliable quantification, namely, (i) the influence of addition of water, of an electrolyte or of a hygroscopic salt, on the release of free fatty acids from the matrix; (ii) the linear relationship between the amount of analyte adsorbed by the SPME polymer film and the initial concentration of the analyte in the cheese sample; and (iii) the competition for adsorption by fiber. Water removal with sodium sulfate promoted a more efficient extraction of volatile free fatty acids; biases due to competition or linear range excesses were controlled by choosing the appropriate amount of sample for each ewe cheese. The method of standard additions was used with success for the quantification of free fatty acids. Calibration curves that were constructed for the major short-chain free fatty acids (butanoic, hexanoic, octanoic, and decanoic acids) spiked into cheese followed linear relationships with highly significant (p < 0.001) correlation coefficients (r > 0.999). Coefficients of variation of <7.9% indicated that the technique was reproducible. A marked increase in concentration of short-chain free fatty acids was observed during cheese ripening, ranging from 0.35 to 9.33 mg/100 g for butanoic acid, 0.363 to 4.34 mg/100 g for hexanoic acid, 0.343 to 2.0 mg/100 g for octanoic acid, and 1.291 to 3.85 mg/100 g for decanoic acid. The limits of quantification were registered at levels of parts per million. The absolute quantification of butanoic acid was also carried out by using isotope dilution assays (IDA). The levels of acid obtained with this method were similar to those obtained by the standard additions method.

Animals↗