Food sensors, sensitive to food properties like pH, water activity are trending issues in food processing and other food related field. Nanoparticles have inspired in the sensory studies owing to their high property of sensitivity and specificity. In this work we intended on the synthesis of silica nanoparticles from agricultural waste materials by acidic method. The synthesized nanoparticles were characterized by Particle size analyzer, Zeta potential, FTIR, XRD and EDX. The sensing property of biogenic SiO2 nanoparticles was achieved by covalently doping FITC dye. The doped nanoparticles were analyzed using Fluorescent spectroscopy for its divergence in excitation intensity according to different pH standard solutions ranging from pH 2 to pH 9. Based on the standard excitation intensity, the pH sensitivity is measured in real time food samples. The FITC dye doped on biogenic SiO2 has a pKa value of 6.5 which makes it a prospective pH indicator. © 2018 World Research Association. All rights reserved.