Physicochemical, Morphological, Pasting, and Rheological Properties of Tamarind (Tamarindus indica L.) Kernel Starch

Starch was isolated from tamarind kernels, which are at present considered as waste. It was compared with corn and mung bean starch for its physicochemical, rheological, and morphological properties. Tamarind kernel starch showed significantly lower amylose content, light transmittance, solubility, and higher swelling power in comparison to corn and mung bean starch. The micrographs of tamarind kernel starch revealed its small oval shape granules with smooth surfaces. X-ray diffraction pattern of tamarind kernel starch was similar to corn starch with strong diffraction peaks at 15, 17, and 23 degrees (2). Changes in storage modulus (G'), loss modulus (G''), and loss tangent (tan ) during heating of starches showed the lowest peak G' for tamarind kernel starch, whereas the highest was observed for corn starch. Changes in G' and G'' during cooling, holding and subsequently heating were also studied. The frequency dependence of G' and G'' of starches measured at 25 and 95 degrees C revealed their weak gel behavior. During cooling tamarind kernel starch showed lower increase in G' in comparison to other starches. Tamarind kernel starch was different from corn and mung bean starch in exhibiting highest peak, breakdown, and lowest setback viscosity. Tamarind seeds have potential as a relatively new, cheap, and underutilized source of starch in food applications.