Preparing Starchy Foods Containing Silver Nanoparticles and Evaluating Antimicrobial Activitiy

Background: Silver has been used from ancient times by humans, and recently nanoparticles of silver have been used in many aspects of human life including as a potent antibacterial agent. Objectives: In the current study a completely green method to prepare silver nanoparticles is reported. Two types of starches (potato and corn starches) were used to produce and stabilize silver nanoparticles. Antimicrobial activities of prepared nanofoods were investigated. Materials and Methods: Nanosilver particles have been produced using high temperature water containing bulk silver nitrate and starch sources. Presence of nanosilver containing particles and formation of the nanoparticles were confirmed using transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy, respectively. The anti-bacterial activity of emulsions made from nanoparticles containing starches was evaluated by assessing minimum inhibitory concentrations (MIC) against the studied standard, and pathogenic bacteria. Results: Findings of the current study indicated that the size and shape of silver nanoparticles depended on the type of starch. For example for a special type of potato starch the cubic silver nanoparticles were obtained whereas for other types of potato starch and corn starch spherical silver nanoparticles were produced. Nanoparticle sizes were mainly about 20 nm, but ranging from 2-30 nm in different situations. Due to the biocompatibility of starch synthesized silver nanoparticles, this method can be used for medicinal purposes. Both kinds of nanosilver containing starch sources have excellent antibacterial activity. Conclusions: The current study indicated that silver nanoparticles produced using different starches had strong antibacterial activities on the studied standard and pathogenic bacteria including gram positive and gram negative.