Studies on thermal behavior and properties of starch isolated from Bruguiera species

Abstract

Mangrove species have been proved as an important coastal bio-resources and most productive ecosystem of the world. In the present attempt, two mangrove species viz., Bruguiera gymnorrhiza and B. cylindrica were selected for starch isolation and characterization. Isolated starch was tested for various physico-chemical and other properties like gelatinization, amyloseamylopectin ratio, foaming capacity, emulsion capacity, particle size analysis through Fourier transform infrared (FT-IR) technique, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and differential scanning calorimetry (DSC). Starch endotherms were analyzed to determine enthalpy (∆H), peak onset (T0), peak maximum (Tp), and peak conclusion (Tc) for both the mangrove species. The gelatinization enthalpy (ΔHG) of the starch from B. gymnorrhiza showed 18.71 J/g which was higher than the starch of B. cylindrica (15.98 J/g). As per particle sizing system, most of the granules ranges from 0.72-0.76 µm in B. gymnorrhiza, while granules in starch of B. cylindrica ranges from 4.5-6.5 µm in size. But SEM analysis revealed that the granules are found to be larger in size. FT-IR spectra showed that isolated starch samples of both the species exhibited slightly similar pattern. XRD patterns showed predominantly C-type crystallinity for both the species. Compared to the range of thermal and other properties of starch, it can be suggested that the range of variability was limited in both the Bruguiera species.