Mycotoxins are secondary metabolites produced by fungi especially those belonging to the genus Aspergillus, Penicillum and Fusarium. Mycotoxin contamination can occur in all agricultural commodities in the field and/or during storage, if conditions are favourable to fungal growth. Regarding animal feed, five mycotoxins (aflatoxins, deoxynivalenol, zearalenone, fumonisins and ochratoxin A) are covered by EU legislation (regulation or recommendation). Transgressions of these limits are rarely observed in official monitoring programs. However, low level contamination by Fusarium toxins is very common (e.g., deoxynivalenol (DON) is typically found in more than 50% of the samples) and co-contamination is frequently observed. Multi-mycotoxin studies reported 75%–100% of the samples to contain more than one mycotoxin which could impact animal health at already low doses. Co-occurrence of mycotoxins is likely to arise for at least three different reasons (i) most fungi are able to simultaneously produce a number of mycotoxins, (ii) commodities can be contaminated by several fungi, and (iii) completed feed is made from various commodities. In the present paper, we reviewed the data published since 2004 concerning the contamination of animal feed with single or combinations of mycotoxins and highlighted the occurrence of these co-contaminations.

No abstract

No abstract

Effect of sourdough fermentation, by different starter culture (lactic acid bacteria Lactococcus lactis ssp. Lactis, Weissella confusa, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus helveticus, and yeast Kluyveromyces marxianus subsp. Marxianus), on antioxidant capacity of rye dough and bread was determined and compared with spontaneous fermentation. The total phenolic content and antioxidant activities assessed using Trolox equivalent antioxidant capacity (TEAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity expressed in terms of Trolox equivalents and of percentage of discoloration, were measured. The results indicate that antioxidant activity of the rye sourdough highly depends on the type of inoculum used for fermentation and the levels of bioactive compounds change during the bread making process. Fermentation process and type of starter culture are tools to increase the bioactive compounds with antioxidant activities of the rye bread.

Bovine lactoferrin (LF) is subjected to thermal processing during isolation for commercial use and while preparing milk products intended for infant nutrition. The present study is focused on the heat-induced structural changes of LF in buffer solution. Fluorescence spectroscopy, molecular modeling, and enzymatic hydrolysis studies were combined to extensively characterize LF thermal behavior. The temperature-induced changes induced on LF conformation were analyzed through intrinsic and ANS fluorescence parameters (intensity, maximum position, and parameter A value), the phase diagram method, and quenching experiments using acrylamide and iodide. A higher exposure of hydrophobic residues was highlighted through the molecular modeling approach, with a decrease in α-helix content from 23.5% to 21.2% when increasing the temperature from 25 °C to 80 °C. The experimental results demonstrate a more flexible conformation of the protein at higher temperature, thus facilitating the enzymatic hydrolysis by thermolysin.

The effect of brewers’ spent grain addition on the thermo-mechanical properties of white and wholemeal wheat flour was investigated. The possibility to improve bread quality and antioxidant properties by using the sourdough fermentation was also considered. Increasing the level of brewers’ spent grain caused the increase of water absorption from 58.1 to 65.2% and from 63.8 to 73.6% in case of white and wholemeal flour, respectively. Similarly, the dough development time increased from 1.27 to 6.18 min, and from 3.37 to 5.42 min. Starch gelatinization significantly increased (p<0.05), while the stability of starch gel, starch retrogradation, and cooking setback significantly decreased (p<0.05) with the level of brewers’ spent grain. The specific volume of the wheat bread significantly decreased (p<0.05) and crumb hardness increased (p<0.05) by incorporation of brewers’ spent grain. Sourdough addition improved bread characteristics and the total phenolic content and antioxidant activity of the bread with brewers’ spent grain.

Banu I., Stoenescu G., Ionescu V., Aprodu I. (2011): Estimation of the baking quality of wheat flours based on rheological parameters of the Mixolab curve. Czech J. Food Sci., 29: 35-44.The Mixolab device in view of the characterisation of the thermo-mechanical behaviour of ten different flours, and establishing the correlations between the rheological parameters of wheat flour supplemented with different additives such as fungal α-amylase, fungal hemicellulase, and fungal xylanase weres exploted. The rheological measurements were performed using the Mixolab, Alveograph, and Rheofermentometer. Our results indicated significant positive and negative correlations between the parameters investigated. The changes of the Mixolab curve trend depended on the amylase doses. Significant correlations were established also between the Mixolab parameters and the results of the baking tests; the β slope, C2, C3, and C4 were positively correlated with the specific volume of the bread. Taking into account the results obtained, we may conclude that Mixolab is a complex device that renders the evolution of the bread during the entire technological process, from the dough making to the starch retrogradation.

No abstract