Impact of temperature and pH on antioxidant activity of green silver nanoparticles fabricated from Ananas comosus peel extracts

Abstract

Silver nanoparticles arose as a new weapon in the development of green synthesis of these nanoparticles using diverse natural resources such as plant leaf, microorganisms, and fruit extracts. Biosynthesis approach by using waste materials from plant is widely used as it is proven to be environmentally and cost friendly method. This study aims to identify the impact of temperature and pH on antioxidant activities of silver nanoparticles fabricated from pineapple (Ananas comosus) peel extract. Different temperature (70°C, 80°C and 90°C) and pH (7, 8 and 9) have been tested to the samples and characterized using UV-Visible Spectroscopy. Then, antioxidant activities of the AgNPs produced using different temperature and pH were determined using free radical scavenging ability on 2,2-diphenyl-2-picrylhydrazyl (DPPH). The results were found at pH 9, the surface plasmon resonance peak for biosynthesized AgNPs was at 425 nm on Day 2 while other treatments took longer time to exhibit the AgNPs peak. Biosynthesized AgNPs treated at temperature 90°C showed the optimum temperature when it exhibited peak at 420 nm on Day 3. The biosynthesized of AgNPs from pineapple peel extracts exhibited potential antioxidant activity in the DPPH scavenging by highest DPPH scavenging percentage is at 84.75% for AgNPs treated at pH 9 and 80.29 % for AgNPs treated at 90°C with concentration of 1000 μg/mL. Temperature and pH gave significant impact in synthesis and increase antioxidant activity of green silver nanoparticles.