Synthesis and characterisation of phosphorylated arrowroot (Maranta arundinacea L.) starch

Abstract

Arrowroot (Maranta arundinacea L.) is a tropical perennial plant cultivated in China, India, South East Asia, South America, and Australia. The rhizome of arrowroot plant contains a significant amount (10-25%) of extractable starch. Arrowroot starch has been known as the most digestible starch, and is often being used for food thickener applications. In this research, an effort has been performed to preliminarily study the potentiality of using arrowroot starch as a raw material for modified starch industries. In particular, the effect of several process parameters on the physicochemical and functional properties of phosphorylated arrowroot starch has been examined. Phosphorylation of arrowroot starch was carried out at temperatures of 110-150 oC and an initial pH level of 9, using a mixture of sodium tripolyphosphate (STPP) and sodium trimetaphosphate (STMP) (ratio of STPP/ STMP=2.5:1 w/w) and an intake of 2.5%-7.5%-w STPP based on dry starch. The experimental result shows that the Degree of Substitution (DS) of the phosphorylated products is accessible in the range of 0.003-0.013. For most of the modified starch products, a significant improvement on solubility (1.70-4.87 %-w/w) and swelling power (4.96-8.63 g/g) has been achieved compared to native arrowroot starch (solubility = 1.67 %-w/w, swelling power = 4.87 g/g). Phosphorylated products also have enhanced paste clarity and water and oil absorption capacity. The result suggests that phosphorylation is a promising method to improve the properties of arrowroot starch.