This study evaluated the possibility to use pomegranate peel: an agro-industrial bay product as a conservative agent for fruit juice. Extraction of active compounds of. Punica granatum L. peels was made by maceration with ethanol and the evaluation of antioxidant and antimicrobial activity were conducted using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and disk diffusion method in agar medium, while self-life tests of orange juice monitoring the pH, total soluble solids, titratable acidity, cloud value, browning index and total mesophilic germs were conducted during 18 days. The results highlighted that pomegranate peel extract (PPE) showed a higher phenol and flavonoid content and strong antioxidant activity with an inhibitory concentration (IC50) of 6.22 μg / mL, as well as the antimicrobial activity indicated a higher inhibitory effect. Furthermore, shelf life tests showed a significant effect on browning index, titratable acidity, and lowering of microbial growth during storage compared to the controls, while pH, total soluble solids, and cloud value are not affected. These results allow us to consider pomegranate peel extract as a potential conservator for healthy and sustainable food.

Reduction of nitrate to nitrogen is critical for wastewater treatment process. The present work proposed a promising approach to improve the activity of denitrifying activated sludge by using low frequency ultrasonic treatment. Batch activity assays showed that when ultrasound was applied, denitrification performance was 2.64 higher than the control. Kinetic analysis of nitrate removal rate versus ultrasonic power and duty cycle was performed to investigate the effect of operational parameters on activated sludge activities. The best stimulating effect was observed at 40 W ultrasonic power and 40% duty cycle. The above results demonstrated that ultrasonic stimulation can be used as a technique for enhancing bacterial activities for water treatment. Studies of other parameters that also affect the denitrification under ultrasound are under way.