Isolation, Physicochemical Characterization and Application of Yam (Dioscorea spp.) Starch as Thickening and Gelling Agent

Abstract

Yam starch of the species Dioscorea alata and D. cayenensis‐rotundata was isolated, characterized by differential scanning calorimetry (DSC), X‐ray diffraction, iodine titration, hot‐stage microscopy and rheology, and compared to potato (Solanum tuberosum) and tapioca (Manihot esculenta) starch. The amylose content of yam starch was around 24% and tended to decrease during postharvest storage. Wide‐angle X‐ray diffraction showed a mixed A‐ and B‐type crystalline packing. Differences between yam starches from different species and varieties were revealed by DSC. However, the largest differences between the different yam starches were found in terms of their rheological behavior. Yam starch shows an intermediate viscosity increase upon initial heating, but a stable viscosity during further thermal treatment in the Viscograph. Hot‐stage microscopy showed a good preservation of the granular yam structure during heating, which is thought to be responsible for a rather high viscosity at low stress paired with a strong shear‐thinning effect. The mechanical properties of yam starch gels suggest that the preservation of the granular integrity upon swelling limits amylose leaching, but that the aging behavior is primarily determined by the short‐term changes of the amylose fraction. Yam starch has potential as thickening and gelling agent in food.

Determination of relevant sensory properties of pounded yams (Dioscorea spp.) using a locally based descriptive analysis methodology

“…Bètè bètè, cells present a more pronounced detachment . More recently, other authors mentioned that the pronounced viscosity increase of Krenglè (D. cayenensis-rotundata) starch upon cooling compared to Bètè bètè and Florido (D. alata) could be due to a high structural rigidity of the swollen granules and/or to an increased aggregation rate of amylose (Brunnschweiler et al, 2005). These findings suggest a higher firmness of D. cayenensis-rotundata's cellular tissue compared to D. alata, which might be linked to the textural measurement of firmness of ''foutou".…”

Potentials of tropical starches as pharmaceutical excipients: A review

“…Dioscorea starch granules have been shown to vary in shape from spherical, oval to polygonal shape depending on the species with granule size ranging from 2 to 50 mm [11]. The XRD pattern of the granules also vary from the B to C-type diffraction pattern depending on the Dioscorea specie [12,13]. Dioscorea starch consists of 18 to 30% AM and the gelatinization temperature ranged from 70 to 928C.…”

Effects of tempering (annealing), acid hydrolysis, low-citric acid substitution on chemical and physicochemical properties of starches of four yam (Dioscorea spp.) cultivars

“…Potato and cassava have been explored as sources of commercial starches, however, yams have been comparatively underutilized (Brunnschweiler et al 2005;Odeku and Picker-Freyer 2007). Moreover, literature is sparse on the effect of tempering, acid hydrolysis and, particularly, low-citric acid-substitution on chemical and physicochemical properties of Nigerian yam cultivars in a comparative manner.…”