In-Vitro Antioxidant and Antimicrobial Activities of Selected Fruit and Vegetable Juices and Fermented Dairy Products Commonly Consumed in Egypt

The antibacterial activities of the juices from fruits and vegetables and different fermented dairy products commonly consumed in Egypt were evaluated for their antioxidative and antimicrobial activities. A combination of biochemical analysis and bioassays to identify potency compounds included the 2,2-diphenyl2-picrylhydracyl hydrate (DPPH) radical scavenging method and Folin-Ciocaulteau total phenol method were used to study the distribution and levels of polyphenols and antioxidants (AOXs) contents. For the antimicrobial activity analysis, seven pathogens strains bacterial inoculated (104 cells/ml) into 20 ml of Mueller-Hinton agar and poured in Petri dishes, using the well diffusion, were added juices of fruits, vegetables and different fermented dairy products. After incubation, antibacterial activity was measured by zone of inhibition (ZOI). The pomegranate juices were highest in their polyphenol content, antioxidant activity compared to all other juices. High significant positive relationship existed between the polyphenolic content and the antioxidant activities of the juices. Only fresh juices of lemon (4.4 mg/well) and fresh pomegranate (3.6 mg/well) had the potency to exhibited inhibition activities towards the seven studied antibiotic resistant microorganisms. Sobya was the only lactic acid fermented dairy products with high antioxidant activity and efficiently inhibited the seven studied antibiotic resistant microorganisms. Lemon and pomegranate juices and fermented sobya may be a good candidate for functional foods as well as for nutraceutical plant based products.