Isolation and physicochemical characterization of calcium oxalate crystals from edible plants

Abstract

Calcium oxalate crystals known as calciphytoliths is commonly found in photosynthestic organism such as lower vascular plants, gymnosperms, angiosperms and algae. The study of crystal morphology is significant as they are linked to the metabolic and differentiation events. Calcium oxalates in plants are water insoluble. The calcium oxalate crystal plays a vital role in calcium regulation, metal detoxification in plants. Calcium oxalate crystals synthesized by plants exhibits specific morphology with unique characteristics. The oxalate is present in various plant crops and it is generally considered to be non-nutrition as the essential minerals are unavailable to human body. The consumption of food containing calcium oxalate increases the chances of kidney and renal failure due to high deposition of calcium oxalate in urinary track. The physicochemical characteristics including composition of food are directly related to cause issues in human body. In the present work, various edible vegetables were screened for calcium oxalate content. Beta vulgaris root, Spinacia oleracea leaf, Amorphophallus paeniifolius root were selected for isolation and characterization of calcium oxalate crystals. Effect of various primary parameters on isolation of calcium oxalate was studied. The maximum mass fraction of aqueous extract of calcium oxalate crystals were optimized at various conditions including specific location of collection point, extraction time, temperature, grinding speed, solid-liquid ratio and number of cycles. The isolated crystals were characterized for its structural, functional, morphological and thermal behavior using X-Ray Diffraction analysis (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM) with Energy Dispersive x-ray Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM) and Thermal Gravimetric and Differential Scanning Calorimeter analysis (TG-DSC) respectively. newline