Arrowroot (Maranta arundinacea L.) is a tropical herb used for its tubers, which contain a highly valuable starch. The leaves and the by-products of starch extraction are fed to livestock.
Arrowroot is a perennial glabrous herb that can grow up to 1.5 m in height. It forms thickets in shaded places. It has shallow roots and many cylindrical fleshy tubers (rhizomes) that can go deeper in the soil than the roots. Arrowroot is many branched. Its stems are slender and each bears one large (10-25 cm long x 3-8 cm broad) ovate and oblong leaf at its end. The flowers are small, white in colour, and borne in panicles (Ecocrop, 2015; Valdes Restrepo et al., 2010).
Arrowroot is mainly cultivated for its starchy tubers. Tubers must be processed within 48 hours of harvest because they are prone to rotting. After being soaked in hot water, they are peeled to remove their fibrous covering in order to prevent a bitter taste and discolouration in the final product. They are then cut into small pieces and grated into a coarse pulp. Macerating the pulp breaks down the tough cells surrounding the starch. The pulp is then washed on screens to separate the starch from the fibrous material. The settled starch is then centrifuged or filtered to further separate it from fibre fines and other soluble material. The separated starch must be quickly dried and ground to powder. The root contains about 20% starch, and 17-18% can be extracted (Cecil, 1992; Kay et al., 1987). Arrowroot starch is one of the purest natural carbohydrates, with a high maximum viscosity. It is used in food preparations and confectionery, such as jellies and pastries. Since it is highly digestible, it is fed to infants and to people with specific dietary requirements. Industrial applications include cosmetics and glue (Göhl, 1982; Ecocrop, 2015). It has several ethnomedicinal applications (Kay et al., 1987).
Production of starch from arrowroot yields several potential feed resources. The aerial biomass of arrowroot that is left in the field can be processed into silage (Erdman et al., 1984). The residue of starch extraction, called "bittie" in the West Indies island of Saint Vincent, has a high fibre content that can be fed to livestock (Erdman et al., 1984; Göhl, 1982; Valdes Restrepo et al., 2010).