S22 - Session O2 - Natural ingredient development using amazonic purple yam (Dioscorea trifida L.f var. morada)

Authors: Maria Soledad Hernandez *, Willian Quintero, Marcela Carrillo, Kimberly Lozano, Luisa Orduz, Juliana Cardona

The purple yam is a sweet-tasting Andean tuber, which grows on the Colombian Amazon region, and exhibits a great importance for local communities. The purple yam is traditionally cultivated by indigenous communities in their communal orchards (called "chagras") to protect their food security and sovereignty. Currently the purple yam is not an industrial crop despite its great potential. Its high anthocyanins content not only causes an impacting purple and brilliant color to the tuber, but also a high antioxidant capacity that can be an advantage for formulating bioproducts that includes it. Its naturally high content of starch gives it a high potential for obtaining natural ingredients for food, cosmetic or pharmaceutical industries, which could boost the local economy. A purple powder can be obtained using a few simple steps process for drying the tuber; although, this powder is insoluble in water, ethanol, and oil. This condition reduces considerably its applications range. Despite of its great potential, little efforts have been done to enhance the solubility in water of this natural ingredient. To overcome this gap, we explored different ways to modify the starch of purple yam, having in mind to reduce the losing the natural properties of the tubercle during the processing. Processes of etherification, esterification, enzymatic cross-linking, and enzymatic hydrolysis have been probed, and compared by the analysis of the ingredient viscosity, anthocyanin content, antioxidant capacity, and changes on the amylose / amylopectin relation. Specifically, the enzymatic hydrolysis process resulted in a starch that had a higher reincorporation capacity with respect to raw starch, going from 2.5% to 11% without significantly affecting starch color or anthocyanin content.