Commercial whey protein concentrate (WPC) was hydrolysed with either Alcalase 2.4 FG (Novo Nordisk), or papain (Sigma) (in one-step process) or with two enzymes (in two-step process) to determine the changes in the immunoreactivity of a-lactalbumin and b-lactoglobulin. Enzymatic hydrolysis of WPC was performed by pH-stat method. Hydrolysates were analysed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis, immunoblotting and size-exclusion chromatography (SE-HPLC). Immunoreactive properties of peptide fractions separated from the hydrolysates by fast protein liquid chromatography (FPLC) were determined using dot-immunobinding and enzyme-linked immunosorbent assay (ELISA) methods. Finally the sensory analysis was used to confirm organoleptic changes resulting from the application of different enzymes. The Ôtwo-stepÕ process was observed to be the most effective however allergenic epitopes were still present, as it was found by ELISA with anti-a-la and anti-b-lg antibodies. The addition of papain as the second enzyme in the hydrolysis process contributed to the improvement of the sensory properties of WPC hydrolysate as compared with the Alcalase hydrolysate. Alcalase-papain partially hydrolysated WPC can be found a promising base for production of the tolerogenic formula.

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RESUMENEfecto de los compuestos fenólícos extraídos de semillas de girasol sobre la actividad lipoxigenasa nativa.Se obtuvieron extractos de lipoxigenasa de semillas de girasol usando 12 mezclas de extracción diferentes, y se determinó la actividad lipoxigenasa y el contenido en compuestos fenólicos. Este último se llevó a cabo mediante medida de la relación de absorbancias a 320/280 nm. El análisis estadístico de los resultados para los extractos mostró una correlación entre la actividad lipoxigenasa y la relación OD32onm/OD28onm con T = 0,619. Sin embargo, después de la diáli-sis de los extractos, no se observó esta correlación. PALABRAS-CLAVE: Compuestos fenólicos -Girasol -Upoxigenasa (actividad). SUMMARYEffect oí phenolic compounds extracted from sunflower seeds on native lipoxygenase activity.Extracts of lipoxygenase were obtained from sunflower seeds using 12 different extraction mixtures, and lipoxygenase activity and content of phenolic compounds in the extracts were determined. The content of phenolic compounds was determined as the ratio of optical densities at 320/280nm. Statistical analysis of the results for the extracts showed a significant correlation between the lipoxygenase activity and the ODaaonm/ODasonm ratio with r = 0.619. However, after dialysis of the extracts, no correlation was found.

The aim of presented studies was to determine the effect of total pea albumins on mice immune system response. Oral and intraperitoneal (i.p.)

The effect of heat induced changes on the immunoreactivity of -lactalbumin ( -la) in whey was evaluated. Whey and acidified -la solutions were heated for various times at temperatures between 60 and 100 °C. After heating, the samples were clarified and the protein content (by Bradford's method), the quantity of -la (by FPLC method) and the immune response to an anti -la probe were determined. The samples heated at 80 °C were characterized by the highest -la immunoreactivity properties. Raising temperature up to 90 °C and 100 °C caused a marked decrease in -la immunoreactivity. As was found by FPLC method in the samples heated at 60 and 65 °C, -la content changes were not statistically significant. A gradual decrease in the content of -la was observed with increased temperature and duration of heating.

Changes of lipase and lipoxygenase specific activities were monitored during wheat and barley germination. Statistically significant correlation (r2 = 0.8148, P < or = 0.02) was found between the specific activities of lipase and lipoxygenase during wheat germination, whereas such correlation did not occur during barley germination.

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