Extracts of wheat bran and barley husk with solvents of different polarity were analyzed to determine the concentration of bioactive compounds (phytic acid, saponins, flavonoids, total phenolic compounds and phenolic profile) and their antioxidant activity by DPPH and ABTS assays. The results showed that the phytic acid concentration in wheat bran was higher than the phytic acid concentration in barley husk. The concentration of saponins was inverse with higher concentrations in barley husk than wheat bran. The solvents with the highest extraction of phytochemicals were 80% ethanol in wheat bran and 50% acetone in barley husk. The chromatograph profile showed that wheat bran presented a greater concentration of caffeic acid and barley husk contained kampferol. The properties of extraction solvents significantly affected the concentration of flavonoids, phenolic compounds, and antioxidant activity. The addition of water to the solvents increased the extraction efficiency of bioactive compounds and antioxidant activity. The results for barley husk are among the first reported because there are few studies on this cereal.

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The objective of this study was to relate the tortilla minimum integral desorption entropy with acrylamide content during processing of tortilla chips. Tortilla pieces were stored at 30 ˚C at aw of 0.11-0.84 for 4 days and fried later in soybean oil at 180 ˚C for 25 s. The lowest acrylamide content was observed in tortilla chips made of non-stored tortilla (aw=0.98) as well as in those prepared from tortilla stored in the minimum integral entropy (aw=0.53). In addition, the color and texture values were similar in both cases. These results suggest that the reduction of the acrylamide content during processing of tortilla chips and other tortilla based foods thermally processed might be modified by factors such as moisture content, aw, and the physical state of water in the tortilla. Thus, the minimum integral entropy showed to be a reliable indicator to establish the most appropriate moisture conditions to obtain tortilla chips with reduced level of acrylamide when tortilla is dehydrated. Highlights Water activity affects the acrylamide content in tortilla chips. Minimum integral entropy is a reliable indicator to establish the most appropriate moisture conditions to get a reduction of acrylamide in tortillas chips. Tortilla dehydration to the minimum integral entropy reduces the acrylamide content. Products obtained from stored tortilla showed an acceptable texture and appearance.

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Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo intemperizados en suelos y sedimentos (Biodegradation modeling of sludge bioreactors of total petroleum hydrocarbons weathering in soil and sediments)