Interactions of different carrageenan isoforms and flour components in breadmaking.

The aim of this study was to compare the effects of carrageenans with different sulfate contents on bread volume and dough rheological properties. Results showed that only lambda carrageenan, the most sulfated isoform, produced a significant increase in bread volume. In contrast, the different carrageenans induced a negative effect on the cookie factor. Alveographic and farinographic analyses indicated that dough rheological properties were differentially modified depending on whether lambda carrageenan was added to flour and then hydrated or vice versa. Analysis of the interaction between lambda carrageenan and flour components by infrared spectroscopy and SDS-PAGE indicated that a pool of low molecular weight hydrophobic gluten proteins interact with carrageenan. This interaction drastically changes their physicochemical properties since carrageenan-gluten protein complexes show a hydrophilic behavior. In addition, the results indicate that carrageenan sulfate groups and probably the amino groups of glutamines present in the primary structure of gluten proteins are involved in the interaction.

Improvement of HDL- and LDL-cholesterol levels in diabetic subjects by feeding bread containing chitosan.

In this work we evaluated the efficacy and safety of a bread formulation containing chitosan in dyslipidemic type 2 diabetic subjects. For this purpose a total of 18 patients were allowed to incorporate to their habitual diets 120 g/day of bread containing 2% (wt/wt) chitosan (chitosan group, n= 9) or standard bread (control group, n= 9). Before the study and after 12 weeks on the modified diet, the following parameters were evaluated: body weight, plasma cholesterol, high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol, triglyceride, and hemoglobin A(1c) (HbA(1c)). Compared with the control group, the patients receiving chitosan-containing bread decreased their mean levels of LDL-cholesterol and significantly increased their mean levels of HDL-cholesterol at the end of the study. There were no significant differences in the body weight, serum triglyceride, and HbA(1c). These results suggest that chitosan incorporated into bread formulations could improve the lipoprotein balance similar to typical biliary salts trappers, increasing the HDL- and lowering the LDL-cholesterol, without changing the triglyceride levels. These results warrant further studies over a longer period of time to evaluate if a persistent improvement in levels of lipoproteins can be attained with this strategy.

Hydrolysis of a chitosan-induced milk aggregate by pepsin, trypsin and pancreatic lipase.

The addition of chitosan to whole milk results in dose dependent destabilization and coagulation of the casein micelles and milk fat. The present study evaluates how the presence of chitosan could affect the hydrolysis of this chitosan-induced aggregate by different gastrointestinal proteases (pepsin and trypsin) and by pancreatic lipase. The chitosan-milk aggregate was hydrolyzed by pepsin and trypsin, as evaluated by the UV absorbance of TCA-soluble peptides and by urea-PAGE. The kinetics and extent of hydrolysis were independent of the casein being soluble or aggregated. The release of soluble peptides from the aggregate was independent of the presence of chitosan. A progressive inhibition of pancreatic lipase was observed in proportion to the increase in molecular weight of the chitosan employed to induce the formation of the aggregate. Interestingly, the presence of chitosan not only affected the initial velocity of the reaction, but also reduced its extent. The results indicate that a milk aggregate induced by chitosan was very well digested by gastric and intestinal proteases independently of the molecular weight of the chitosan used, and that the aggregate could retain the lipid-lowering effect of chitosan.

Characterization of casein micelle precipitation by chitosans.

We have found that the addition of chitosan, a cationic polymer, on whole or skim milk produces destabilization and coagulation of casein micelles that takes place without changes in the milk pH or the stability of most whey proteins. The amount of lipids recovered in the chitosan-casein aggregates was similar or higher than that obtained with rennet or acid precipitation. Approximately 70% of milk Ca2+ (approximately 750 mg/L) was found in the chitosan-induced aggregates, which is 10 and 50% higher than the amounts observed with acid or rennet coagulations, respectively. Purified alpha, beta-, and kappa-caseins were extensively precipitated by different molecular weight chitosans at pH 6.8. The phosphate groups of caseins seem not to be relevant in this interaction because dephosphorylated alpha- and beta-caseins were equally precipitated with chitosans. Analysis by optical microscopy of the chitosan-casein complex reveals that the size of the aggregates increase as the molecular weight of chitosans increase. Hydrophobic and electrostatic interactions particpate in the association and coagulation of casein micelles with chitosans of different molecular weights. The phenomenon is observed over a broad range of temperature (4 to 70 degrees C) with a reduction in the concentration of chitosan needed to precipitate the caseins that parallels a reduction in the viscosity of the chitosan solutions. Taken together, the results indicate that the electrostatic interactions may contribute energetically to the association between the two biopolymers, but the hydrophobicity of the complex would be the key determinant in the overall energetics of the reaction.

Treatment of rheumatoid arthritis by oral administration of bovine tracheal type II collagen.

We evaluated the efficacy and safety of orally administered bovine tracheal type II collagen (CGII) in the treatment of rheumatoid arthritis (RA). Twenty RA patients received 0.5 mg/day of CGII for 12 weeks. Eighteen of them had improvements in the clinical parameters studied (swollen and tender joint counts, 15-m walking time, duration of morning stiffness, and physician's global assessment of disease activity). Anti-CGII antibodies were positive in 57% and rheumatoid factor (RF) in 71% of the patients with a short history of RA ( < or =2 years), whereas only 23% of those with long histories (>2 years) presented autoantibodies to CGII and 38% had positive RF. After the treatment, four patients showed reduced RF levels and all those with detectable serum tumor necrosis factor alpha (TNF-alpha) experienced its return to normal or levels below those at study entry. Although a placebo effect cannot be discounted, the oral administration of bovine tracheal CGII induced clinical benefits in 90% of the patients, without the side effects usually associated with treatment. This is the first study showing that feeding CGII can induce reductions in RF and TNF-alpha. The data justify further controlled studies to assess the long-term efficacy of this treatment approach.

Prevalencia de anticuerpos antitiroglobulina y antimicrosomales en enfermedad tiroidea autoinmune / Antithyroglobulin and microsomal antibodies prevalence in autoimmune thyroid disease

Objetivo: Analizar la prevalencia de anticuerpos antitiroideos en enfermedades tiroideas, su relación con variables clínicas y epidemiológicas, y su utilidad diagnóstica. Métodos: Se determinaron anticuerpos antimicrosomales y antitiroglobulina por aglutinación de partículas de gelatina en 32 pacientes sanos (25 mujeres, 7 hombres) y 108 (92 mujeres, 16 hombres) con enfermedad tiroidea; diagnosticados por examen clínico, confirmados por laboratorio y cuando fue necesario por ecografía, pruebas de captación, biopsia y otras. Se consideró la patología, edad y sexo de los pacientes. Resultados: Las enfermedades tiroideas autoinmunitarias predominaron sobre las no autoinmunes en la población estudiada, 64,8 por ciento vs 35,2 por ciento. Los anticuerpos antimicrosomales fueron positivos en altos títulos en la mayoría de los pacientes con enfermedad de Graves y Hashimoto, mientras que pacientes con enfermedades tiroideas no autoinmune presentaron baja frecuencia. La prevalencia de anticuerpos anti tiroglobulina en enfermedades tiroideas autoinmunes fue significativamente menor a la de antimicrosomales, (44,3 por ciento vs 98,6 por ciento p<0,05). Aunque no fue estadísticamente significativo, se encontró cierta asociación entre enfermedades tiroideas autoinmunes y otros desórdenes autoinmunes (Enfermedad de Addison) y no autoinmunes (Diabetes mellitus tipo II). No hubo relación entre parotiditis previa y autoinmunidad tiroidea. Los anticuerpos antimicrosomales mostraron mayor sensibilidad que los antitiroglobulina (98,6 por ciento y 44,3 por ciento), con especificidad comparable (85,7 por ciento y 95,7 por ciento). Conclusiones: Debido a la mayor prevalencia y sensibilidad presentada por los anticuerpos antimocrosomales, el diagnóstico de tiroiditis autoinmune podría basarse en la valoración de dichos anticuerpos, con determinación de anticuerpos antitiroglobulina en casos especiales. Existen factores hereditarios involucrados en el desarrollo de enfermedades autoinmunes tiroideas