Characterization of arrowroot (Maranta arundinacea) starch as a potential starch source for the food industry

Arrowroot is an underutilized tuber crop in Sri Lanka and the characterization of starch was done to identify its nutritional, physicochemical, and functional properties to evaluate its potential for use in the food industry. This study distinctly advances the field of arrowroot starch characterization by providing more characterization techniques for starch samples from Sri Lanka. Arrowroot starch colour was closely similar to colour of wheat flour indicating that the effect of colour is minimum when replacing wheat flour. Oval, spherical, and irregular globular shapes were the predominant starch granule shapes for arrowroot. The average length of starch granules was 44.99 ± 1.27 μm while the width of granules was 31.44 ± 0.58 μm. The least gelation concentration was 8.0% indicating its better gel-forming ability. The nutritional composition of arrowroot starch consisted of low crude protein (0.72 ± 0.02%), crude fat (0.26 ± 0.19%), and crude fiber (1.00 ± 0.09%) contents indicating the purity of starch. Sodium, Potassium, Calcium, Iron, and Zinc contents were 52.6 mg/kg, 4312.95 mg/kg, 382.67 mg/kg, 9.07 mg/kg, and 2.59 mg/kg, respectively. Results of flour densities demonstrated the potential of arrowroot starch to be used in the pharmaceutical industry. Arrowroot starch had high viscosity defining its potential as a thickener. The starch also had high swelling power and solubility indices while solubility was positively correlated with viscosity (0.679; P > 0.05). The low moisture absorbance indicates a longer shelf life of stored arrowroot starch. Onset temperature (T(o)) of 75.02 °C, peak temperature (T(p)) of 77.95 °C, and conclusion temperature (T(c)) of 82.43 °C were resulted from DSC thermogram. Arrowroot was identified as an A-type starch from x-ray diffractometry and the FT-IR spectrum of arrowroot was identical to starch and presented the carbohydrate nature of starch. Thus, arrowroot starch has a high potential to be used in the food industry based on its functional properties.