Modeling the combined resistance to microwave treatments and salt conditions of Escherichia coli and Staphylococcus aureus.

In the present study, the efficiency of the combined effect of microwave irradiation treatments together with salt concentration was assessed against Escherichia coli and Staphylococcus aureus. Microbial survival has been modeled through a one-step Weibull equation considering the non-isothermal profiles during the heating treatments. Three sodium chloride concentrations 0.5%, 3.5%, and 8.5% (w/v) treated under three microwave power levels (450, 600, and 800 W) were studied. Predictive models were validated using the determination coefficient (R2), root mean squared error and the acceptable prediction zone with external data obtained from ultra high temperature milk. The results obtained suggested that increasing microwave power levels and decreasing salt concentrations led to a higher microbial inactivation, being the δ values (time for achieving a first decimal reduction) for E coli of 19.57 s at 800 W and 0.5% NaCl. In contrast, experimental data of S aureus showed a higher variability since it presented more resistance to the microwave treatments. The results obtained and generated models can be used as decision-making tools to set specific guidelines on microwave treatments for assuring food safety.

Effect of precipitation solvent on some biological activities of polysaccharides from Pinus halepensis Mill. seeds.

This study was designed to evaluate, for the first time, the effect of the precipitation solvent (Acetone, Ethanol, and Propanol) on the antioxidant, anti-inflammatory and anticoagulant activities of the polysaccharides extract from Aleppo pine seeds. The antioxidant activity was evaluated with different tests (ABTS, DPPH, metal chelation, ferric reducing power, antiperoxidation and ORAC tests), the anti-inflammatory activity was assessed with three tests (denaturation protein inhibition, antiproteinase and anti-hemolytic tests). Finally, the anticoagulant activity was tested by endogenous and exogenous ways. The three extracts (AP: acetone polysaccharides extract, EP: ethanol polysaccharides extract and PP: propanol polysaccharides extract) have exhibited a very interesting activities but with different degrees. The AP extract was most effective in almost all antioxidant activities (antiradical ABTS and DPPH, metal chelation, reducing power and ORAC), in two in vitro anti-inflammatory and the anticoagulant activities. However, for the lipid antiperoxidation activity, it was the PP extract that gave better activity. The best antiproteinase activity was expressed by the EP extract. These results indicate that polysaccharides of Aleppo pine seed may be considered as a source of bioactive polysaccharides and the precipitation solvent of the polysaccharides has a major effect on the intensity of the bioactivity of these polysaccharides.