Natural derived ingredients development from amazonic purple yam (Dioscorea trifida L.f var. morada)

The purple yam is a sweet-tasting Andean tuber, which grows in the Colombian Amazon region, and exhibits great importance to local communities. Its high anthocyanins content not only confers an impacting purple and brilliant color to the tuber, but also a high antioxidant capacity that can be an advantage for formulating functional bioproducts. Its naturally high starch content 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 application range. Despite its great potential, little effort has 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 minimize the lost of the natural properties of the tubercle during the processing. Processes of etherification,, enzymatic cross-linking, chemical andenzymatic hydrolysis have been probed and compared by the analysis of the ingredient viscosity, anthocyanin content, antioxidant capacity, and changes in the amylose/amylopectin relation. Specifically, the enzymatic hydrolysis process resulted in starch that had a higher reincorporation capacity compared to raw starch, going from 2.5 to 11% without significantly affecting starch color or anthocyanin content.