Photo-mediated biosynthesis and characterization of silver nanoparticles using bacterial xylanases as reductant: Role of synthesized product (Xyl-AgNPs) in fruits juice clarification

In the present context, sunlight-irradiation based synthesis of silver nanoparticles (AgNPs) was performed using bacterial xylanase as reductant (Xyl-AgNPs) and evaluated its potency towards the clarification of three fruits [Mangifera indica (mango), Punica granatum (pomegranate), and Ananas comosus (pineapple)] juices. Initially, the synthesis of Xyl-AgNPs was confirmed by the reduction of silver ions which showed the formation of dark red colour solution due to the reaction of xylanase and silver nitrate. Ultraviolet-Visible (UV–Vis) spectrum of the biosynthesised AgNPs depicted the surface plasmon resonance peak at 452 nm. Zeta potential value of AgNPs indicated a positive surface charge of +4 mV. The synthesized AgNPs was observed spherical in shape with an average size of 100 nm. Fourier transform-infrared (FT-IR) spectrum confirmed the presence of varied functional groups in AgNPs. Fresh fruits (mango, pomegranate, and pineapple) juices were clarified using bacterial xylanase and Xyl-AgNPs at various incubation temperature (30–60⁰C) for 30–120 min as per standard methodologies. Results showed comparatively higher clarification and reducing sugars production due to the supplementation of Xyl-AgNPs into the juices with respect to the addition of partially purified xylanase at various temperature and incubation period. In a nutshell, findings of this investigation suggested the pivotal role of Xyl-AgNPs in the clarification of fruit juices for distinct applications in food processing industries.