TRAINING, VALIDATION AND MAINTENANCE OF A PANEL TO EVALUATE THE TEXTURE OF DRY BEANS (PHASEOLUS VULGARIS L.)

The inclusion of dry beans in diets has clear health benefits. However, consumers in developed countries mainly choose beans for their sensory qualities, especially for their texture. This article describes the constitution, training and validation of a panel of judges to evaluate the texture of dry beans. The judges were trained in the perception of different textures, analyzed a wide range of beans and selected seed-coat roughness, seed-coat perceptibility and creaminess/mealiness of the cotyledon as the main attributes to be scored. After training, the panel was capable of discriminating between different varieties of beans and even between beans of the same variety grown at different locations. The analysis of the behavior of the panel in a standard tasting session 2 years after its formation showed that periodic inclusion of samples from the extremes of the scales for the attributes during tasting sessions was sufficient to keep the panel trained.

PRACTICAL APPLICATIONS

This article could serve as a guide for the training of sensory panels to evaluate the texture of dry beans. It describes the selection of the attributes on which the analysis is based, references for the extreme values of the attributes and how to train the panel. It also provides a practical example of the analysis of the behavior of the panel some time after training.     

Increased sulfate uptake by E. coli overexpressing the SLC26-related SulP protein Rv1739c from Mycobacterium tuberculosis.

Growth and virulence of mycobacteria requires sulfur uptake. The Mycobacterium tuberculosis genome contains, in addition to the ABC sulfate permease cysTWA, three SLC26-related SulP genes of unknown function. We report that induction of Rv1739c expression in E. coli increased bacterial uptake of sulfate, but not Cl(-), formate, or oxalate. Uptake was time-dependent, maximal at pH 6.0, and exhibited a K(1/2) for sulfate of 4.0 muM. Na(+)-independent sulfate uptake was not reduced by bicarbonate, nitrate, or phosphate, but was inhibited by sulfite, selenate, thiosulfate, N-ethylmaleimide and carbonyl cyanide 3-chloro-phenylhydrazone. Sulfate uptake was also increased by overexpression of the Rv1739c transmembrane domain, but not of the cytoplasmic C-terminal STAS domain. Mutation to serine of the three cysteine residues of Rv1739c did not affect magnitude, pH-dependence, or pharmacology of sulfate uptake. Expression of Rv1739c in a M. bovis BCG strain lacking the ABC sulfate permease subunit CysA could not complement sulfate auxotrophy. Moreover, inducible expression of Rv1739c in an E. coli strain lacking CysA did not increase sulfate uptake by intact cells. Our data show that facilitation of bacterial sulfate uptake by Rv1739c requires CysA and its associated sulfate permease activity, and suggest that Rv1739c may be a CysTWA-dependent sulfate transporter.     

Rhythm of Protein Synthesis in Cultures of Hepatocytes from Rats of Different Ages. Norm and Effect of the Peptide Lyvagen

The circumhoralian rhythm of protein synthesis was determined in a monolayer culture of hepatocytes from rats at the age of 1 to 24 months and weighing from 45 to 480 g, respectively. The peptide lyvagen (Lys-Glu-Asp-Ala) obtained by directed chemical synthesis on the basis of amino acid analysis of the liver polypeptide preparations increased the level of protein synthesis in the hepatocytes from rats of different ages; the highest effect was observed in the cells of old animals. In old rats, lyvagen increased the amplitude of protein synthesis fluctuations. The peptide epitalon (Ala-Glu-Asp-Gly) constructed on the basis of analysis of the epiphysis peptides did not change the intensity of protein synthesis in the cultured hepatocytes.     

COMPARISON OF TWO SIMPLE METHODS FOR THE MEASUREMENT OF DETECTION THRESHOLDS FOR BASIC, UMAMI AND METALLIC TASTES

Two simple methods were followed to determine detection thresholds for the taste of substances in aqueous solution. The methods applied were: a modification of the ascending method of limits and a method based on the use of scales. Detection thresholds were calculated for the four basic tastes (sweet, salty, acid, and bitterness), umami and metallic. Reference substances for each taste were sucrose, sodium chloride, citric acid, caffeine, monosodium glutamate and iron (II) sulfate heptahydrate and the results of the two methods were compared. We found that the threshold values calculated by method ASTM-679 was within the range of concentrations identified with the scales method.     

Strain-specific differences in <Emphasis Type="Italic">Neisseria gonorrhoeae</Emphasis> associated with the phase variable gene repertoire

Background  

There are several differences associated with the behaviour of the four main experimental Neisseria gonorrhoeae strains, FA1090, FA19, MS11, and F62. Although there is data concerning the gene complements of these strains, the reasons for the behavioural differences are currently unknown. Phase variation is a mechanism that occurs commonly within the Neisseria spp. and leads to switching of genes ON and OFF. This mechanism may provide a means for strains to express different combinations of genes, and differences in the strain-specific repertoire of phase variable genes may underlie the strain differences.     

Genetic islands of <Emphasis Type="Italic">Streptococcus agalactiae</Emphasis> strains NEM316 and 2603VR and their presence in other Group B Streptococcal strains

Background  

Streptococcus agalactiae (Group B Streptococcus; GBS) is a major contributor to obstetric and neonatal bacterial sepsis. Serotype III strains cause the majority of late-onset sepsis and meningitis in babies, and thus appear to have an enhanced invasive capacity compared with the other serotypes that cause disease predominantly in immunocompromised pregnant women. We compared the serotype III and V whole genome sequences, strains NEM316 and 2603VR respectively, in an attempt to identify genetic attributes of strain NEM316 that might explain the propensity of strain NEM316 to cause late-onset disease in babies. Fourteen putative pathogenicity islands were described in the strain NEM316 whole genome sequence. Using PCR- and targeted microarray- strategies, the presence of these islands were assessed in a diverse strain collection including 18 colonizing isolates from healthy pregnant women, and 13 and 8 invasive isolates from infants with early- and late-onset sepsis, respectively.     

Characteristics of Non-opioid β-Endorphin Receptor

Tritium-labeled selective agonist of non-opioid beta-endorphin receptor, the decapeptide immunorphine ([3H]SLTCLVKGFY) with specific activity of 24 Ci/mmol has been prepared. By its use, non-opioid beta-endorphin receptors were revealed and characterized on mouse peritoneal macrophages and rat myocardium, spleen, adrenal, and brain membranes. The non-opioid beta-endorphin receptor of macrophages has in addition to immunorphine (Kd of the [3H]immunorphine-receptor complex was 2.4 +/- 0.1 nM) and beta-endorphin (Ki of the [3H]immunorphine specific binding was 2.9 +/- 0.2 nM) a high affinity for Fc-fragment of human IgG1, pentarphine (VKGFY), cyclopentarphine [cyclo(VKGFY)], and [Pro3]pentarphine (VKPFY) (Ki values were 0.0060 +/- 0.0004, 2.7 +/- 0.2, 2.6 +/- 0.2, and 2.8 +/- 0.2 nM, respectively) and is insensitive to naloxone and [Met5]enkephalin (Ki > 100 microM). Treatment of macrophages with trypsin resulted in the loss of their ability for the specific binding of [3H]immunorphine. Values of the specific binding of 8.4 nM [3H]immunorphine to rat adrenal, spleen, myocardium, and brain membranes were determined to be 1146.0 +/- 44.7, 698.6 +/- 28.1, 279.1 +/- 15.4, and 172.2 +/- 1.8 fmol/mg protein, respectively. Unlabeled beta-endorphin, pentarphine, [Pro3]pentarphine, cyclopentarphine, cyclodipentarphine [cyclo(VKGFYVKGFY)], and Fc-fragment of IgG1 inhibited the binding of [3H]immunorphine to membranes from these organs. No specific binding of [3H]immunorphine to rat liver, lung, kidney, and intestine membranes was found.     

CHANGES IN CHEMICAL, SENSORY AND RHEOLOGICAL CHARACTERISTICS OF MANCHEGO CHEESES DURING RIPENING

Manchego cheese is a high-fat pressed ewe's-milk cheese made in Castilla-La Mancha (Spain) and produced by enzymatic coagulation. The minimum ripening time before marketing required by the Regulatory Board of the Manchego Cheese Appellation of Origin is 60 days.
This paper describes the physicochemical, proteolysis, sensory and texture characteristics of Manchego cheese, and the degree of homogeneity of cheeses made under the Manchego Appellation of Origin. The data gathered in this study indicate that sensory and instrumental analysis are useful tools for detecting changes in Manchego cheese during ripening. These changes were first detected by the instrumental analysis (2 months). The panelists detected differences after 4 months' ripening in all the factories. With physicochemical analysis, on the other hand, longer ripening times (6–8 months) are required before such changes become appreciated.