GREEN SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM AQUEOUS EXTRACT OF BASELLA ALBA AND THEIR IN-VITRO ANTIOXIDANT POTENTIALS

Objective: To synthesize silver nanoparticles (AgNps) from Basella alba(B. alba) aqueous extract using 3 mM AgNO3 solution, to characterize the resulted AgNps and also to study the antioxidant activity by DPPH and reducing assay. Methods: 150 ml of aqueous extract was mixed with 600 ml of 3 mM silver nitrate solutions and kept at room temperature for 1hr. A change from straw yellow to golden yellow was observed and absorption spectra were obtained by UV-VIS spectrometer. The resulted nanoparticles (NPs) were characterized by FT-IR spectrum, SEM-EDS, TEM and XPS techniques. The purity and nature of the particles were observed through TG-DSC analysis. Further, Antioxidant activity was performed by DPPH (2, 2-diphenyl-1-picrylhydrazyl) method and by Ferric chloride reducing assay. Results: UV-Vis spectral analysis shows a maximum absorption peak at 435 nm. FT-IR spectrum indicated the formation of reducing and capping agents in AgNps. The synthesized silver nanoparticles was spherical in shape and its size ranges from 22.6 to 25 nm. The synthesized silver nanoparticles possess excellent antioxidant activity by various methods. The phenol carboxylic acid present in B. alba leaf extract acted as a reducing agent which was identified by HPTLC technique. A Protein present in the B. alba extract was responsible for the capping of bio-reduced silver nanoparticles. Conclusion: It has been demonstrated that Basella alba plant extract could be used as a proficient green reducing agent for the synthesis of AgNPs. Further studies will be focused towards the mass scale production of formulation

Nanotechnology and Plant Extracts as a Future Control Strategy for Meat and Milk Products

Plant extracts, well known for their antibacterial and antioxidant activity, have potential to be widely used preservatives in the food industry as natural alternatives to numerous synthetic additives which have adverse impacts on health and the environment. Most plant compounds and extracts are generally recognized as safe (GRAS). The use of preservatives is of great importance for perishable foods such as meat and milk, which, along with their products, are commonly consumed food items globally. However, the bioavailability of plant compounds could be diminished by their interaction with food components, processing, and storage. Nanoencapsulation of plant extracts, especially essential oils, is an effective method for their application in food model systems. This technique increases the bioactivity of plant compounds by increasing their physical stability and reducing their size, without negative effects on organoleptic properties. Furthermore, a recent study showed that plant extracts act as good bioreductants for biosynthesis of nanoparticles. This so-called green synthesis method using plant extracts is a rapid, relatively inexpensive, safe, and efficient method for synthesis of nanoparticles including silver, gold, iron, lead, copper, cobalt, palladium, platinum, zinc, zinc oxide, titanium oxide, magnetite, and nickel. Some of these nanoparticles have antimicrobial potential which is why they are of great interest to the food industry. In this chapter, the nanoencapsulation of plant extracts and plant extract-mediated synthesis of nanoparticles and their potential application in order to improve the safety and quality and prolong the shelf life of meat and milk products are reviewed and discussed