Evaluation of antioxidant and antibacterial activities of fresh and freeze-dried selected fruit juices

Abstract

Objective: The objective of this investigation was to assess the biological activity of fresh fruit juices and freeze dried fruit juices including antioxidant and antibacterial activity. Methods: The fruits used in this study were Schleichera oleosa (Lour.) Oken, Carissa carandas L., and Sandoricum koetjape (Burm.f.) Merr. The fresh juice sample (FJS) was extracted and also prepared for freeze drying sample (FDS) by freeze dryer. The antioxidant capacity of FJS and FDS was assessed using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assays and determination for total phenolic contents (TPCs) by Folin–Ciocalteu’s reagent. Antimicrobial tests were carried out by agar diffusion methods and evaluated by measuring the zone of inhibition against 10 isolates of pathogenic bacteria. Results: The highest antioxidant activity of FJS and FDS was found in S. oleosa and related to the scavenging effect on DPPH radical of FJS (100% concentration) and FDS (200 mg/ml) was found in the value of 93.05±0.31% and 82.18±0.33%, respectively. TPC of FJS and FDS from S. oleosa at the same concentration as in the DPPH assay was 1,003.53±1.96 ug GAE/300 g of matter and 827.77±23.15 ug GAE/100 ml of matter, respectively. Both FJS and FDS revealed antibacterial activity. The zone of inhibition of FJS was ranging from 8.3±0.6 to 24.0±1.0 mm and FDS values of 7.3±0.5-21.0±0.9 mm. The most potent sample against bacteria was FJS and FDS from S. oleosa which FJSs against Escherichia coli ESBL and FDS against Pseudomonas aeruginosa MDR2. Conclusion: Fruit juices of S. oleosa, C. carandas, and S. koetjape associated with antioxidant activity in the form of both fresh fruit juices and FDS. The result of this study showed that the value of DPPH and TPCs were slightly decreased in FDS compare with fresh juice. Screening of FJS and FDS of C. carandas revealed broad spectrum antibacterial activity. However, FJS of S. oleosa and S. koetjape showed inhibition of growth of bacteria, but few of FDS from these fruits could inhibit limited bacterial isolates. For antibacterial activity against pathogenic bacteria, the samples of fresh and freeze dried exhibited a different degree of activity.