A concise review of yam (Dioscorea spp.) starch: extraction, chemical composition, physicochemical properties and its potential food applications

Abstract

Substantial studies have been conducted on the starches derived from various yam species. These studies have examined numerous extraction methods, including acid, alkali, ammonia, water and enzymatic techniques, each yielding between 10–20% starch. The physicochemical properties of yam starches have been extensively characterized, evaluating factors, such as granule size, amylose content (ranging from 0 to 40%), gelatinization behavior and rheological profiles. Notably, the yam species D. esculenta and D. dumoterum exhibit lower amylose levels, while D. trifida can present as a waxy starch with less than 2% amylose. Minimal variation has been observed in the composition, patterning and characteristics across D. cayenensis and D. rotundata starches. Yam tubers are composed of 60–80% starch by dry matter, playing a fundamental role in the quality of yam-based foods. Yam starches have demonstrated potential as thickeners, fat replacers and edible film formers due to their physicochemical attributes, particularly their gelling properties which enhance texture and functionality. However, the industrial utilization of yam starches remains limited due to a lack of systematic data and standardized isolation methods. Further research is needed to optimize extraction protocols and expand the food applications of this versatile starch.