Malgorzata A. Bryszewska

Changes in the chemical form of selenium observed during the manufacture of a selenium-enriched sourdough bread for use in a human nutrition study

High-performance liquid chromatography interfaced with inductively coupled plasma mass spectrometry, and hydride generation-inductively coupled plasma mass spectrometry were used, respectively, to investigate changes in both the chemical form and the concentration of selenium during its bio-incorporation and bio-accumulation into rye seedlings. A 60-fold increase in the total level of selenium in the seedlings (‘control’ biomass = 0.99 mg kg−1, ‘enriched’ biomass = 55.27 mg kg−1) was accompanied by a change from selenite to several organo-selenium forms, with more than 40% being present as selenomethionine. The seedling biomass was dried, ground and used as an ingredient in the production of a fermented sourdough bread (popular in Poland and many Eastern European countries). The selenium in the resulting bread was also characterized in terms of its speciation, as well as its total selenium content (‘control’ bread = 0.06 mg kg−1, ‘enriched’ bread = 3.56 mg kg−1). The breads were then fed to 24 volunteers as part of a human intervention study designed to establish the efficacy of this mode of selenium supplementation. The human study data subsequently showed the bread was a good source of dietary selenium.

The use of transglutaminase in the reduction of immunoreactivity of wheat flour

Abstract The immune response of wheat flour modified by the treatment with transglutaminase under different conditions of temperature, incubation periods and the ratio of enzyme/wheat flour was investigated. The particular wheat protein fractions were examined for the immune reaction by the use of an indirect non-competitive ELISA. Commercially available antibodies, namely, monoclonal antihuman IgG and monoclonal antihuman IgE conjugates with alkaline phosphatase and human sera with elevated IgG as well as rabbit sera against QQQPP peptide were tested. The highest decrease in gliadins immunoreactivity was observed for wheat flour modified under following conditions: temperature 37°C, 18 h of incubation and the ratio enzyme/wheat flour 1:10 000. For all rabbit sera examined the residual immunoreactivity of glutenins was found to be below 30% of the level measured for the untreated protein. The large decrease in allergenicity of glutenins leads to the conclusion that wheat flour modified by treatment with transglutaminase may be used as a constituent of food products destined for people with a classic food allergy, i.e. the allergy elicited by that protein fraction.

Decrease of wheat flour allergenicity via lactic acid fermentation

Abstract Results of the research on the lowering of allergenicity of wheat flour fermented using homo- and heterofermentative lactic acid bacteria and mixed cultures with yeast were discussed. The gliadins’ immunoreactivity was measured using the indirect non-competitive enzyme-linked immunosorbent assay method. The biggest decrease of the immunoreactivity of gliadin fraction was observed in the case of fermentation performed with the use of mixed cultures of lactic acid bacteria and yeast. This way of wheat flour modification seems to be promising, because fermentation is a natural process causing not only lowering of the allergenicity, but also improving organoleptic and nutritional values of obtained products.

Evaluation of arsenic biotransformation by Iberian green frog during metamorphosis

This study examined the effects of arsenic exposure and the biotransformation capacity of developing Iberian green frogs (Rana perezi) with the main aim of finding valid biomarkers to monitor pollution and toxicological problems. Total arsenic concentration and arsenic species distribution were determined using liquid chromatography coupled with inductively coupled plasma-mass spectrometry (LC-ICP-MS). The level of accumulation of arsenic and its species distribution differed depending on the metamorphosis stage and level of exposure. Tetramethylarsonium cation was the major compound detected and continuously increased in concentration during frog development. Results suggest that rather low As accumulation is obtained and that Rana perezi metabolised arsenic during embryonic and larval development.

Direct Arsenic Determination in Exposed Embryos of Zebrafish (Danio rerio) with Zeeman Electrothermal Atomic Absorption Spectrophotometry

ABSTRACT Several methods of analysis have been evaluated for the determination of the arsenic content in zebrafish embryos (Danio rerio). The methods have been developed based on waste minimization, while sample treatment was exploited to attend the standards of clean chemistry. The ultimate goal of developing a method to directly introduce whole single embryos into the electrothermal furnace atomic absorption spectrometer (ETAAS) was accomplished after optimization of instrument parameters and matrix modifiers. The significant matrix effects due to the complexity of the sample were overcome by the use of a palladium modifier and hydrogen peroxide as an oxidizing agent to aid in the mineralization of the sample during the pyrolysis. The results obtained from this direct method for arsenic analysis were in agreement with those from more common sample preparation methods of acid digestion or ultrasonic extraction. The speed of the ultrasonic method and use of environmentally safe reagents makes this a more favorable technique than acid digestion. The single embryo direct introduction method, however, is preferred due to its ability to measure whole single samples without any sample pretreatment, and furthermore allows for evaluation of the variability of arsenic accumulation between individual samples. The ETAAS method developed has been validated by inductively coupled plasma mass spectrometry (ICP-MS).

Bioavailability of Microencapsulated Iron from Fortified Bread Assessed Using Piglet Model

The aim of this study was to investigate the influence of oral iron supplementation, in the form of fortified breads, on the growth performance, health, iron status parameters, and fecal metabolome of anemic piglets. A study was conducted on 24 hybrid (Large White × Landrace × Duroc) piglets. From day 44, the post-natal 12 piglets were supplemented with 100 g of one of two experimental breads, each fortified with 21 mg of ferrous sulphate, either encapsulated or not. After one week of oral supplementation, hematological parameters (hematocrit value, hemoglobin, and red blood cells) showed statistically significant differences (p ≤ 0.05). Piglets fed with the fortified breads had higher iron concentrations in the heart, liver, and intestinal mucosa compared to anemic piglets fed with control bread. Gene expression of hepcidin, iron exporter ferroportin (IREG1), and divalent metal transporter 1 (DMT1), together with concentrations of plasma ferritin, showed no significant statistical differences between groups. Both fortified breads could be used as sources of bioavailable iron. The seven-day intervention trial showed microencapsulation to have only a mild effect on the effectiveness of iron supplementation in the form of fortified bread.