Analysis of the Material and Tablet Formation Properties of four Dioscorea Starches

Abstract

The material and tablet formation properties of starches from four different Dioscorea species, namely White (D. rotundata), Bitter (D. dumetorum), Chinese (D. oppositifolia) and Water yam (D. alata), was characterized to determine their applicability as direct compression excipient. The physicochemical, thermal, morphological and material properties of the starches were investigated. The tablet formation properties were assessed using the 3‐D modeling parameters, the Heckel equation and the force‐displacement profiles. The tablet properties were evaluated using the elastic recovery and compactibility plots. The results indicate that the chemical composition, thermal and material properties of the starches varied considerably among the four species. The sorption isotherms show that the relative humidity (RH) during tablet production and storage should be carefully controlled. The tableting results show that all four starches exhibit similar time dependent deformation (d). The ranking for pressure plasticity (e) was Water > Chinese > White > Bitter, which indicates that Water deforms more easily and Bitter less easily. The ranking for fast elastic decompression was White > Water ≥ Chinese > Bitter. The amylose content, size and shape of the starch granules and specific surface area appears to play a significant role in the compressibility. Thus, White and Water with larger granules and high amylose content exhibited poor compressibility and did not form compacts except at high ρrel,max, while Bitter and Chinese with polygonal shape, small particle size and high specific surface area were more compressible and formed tablets of acceptable crushing force. Thus, Chinese and Bitter could be useful as excipient in direct compression.

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

“…Crude fibre was not detected, while the crude fat of the starches ranged from 0.11 to 0.69%. Comparable values of crude fat for native yam starches (0.28-0.69%) have been reported (Rugchati and Thanacharoenchanaphas 2010;Odeku and Picker-Freyer 2007;Zuluaga et al 2007). Modification of the starches significantly reduced the crude fat contents.…”

“…Native bitter yam starch had higher crude protein than other native yam starches, indicating that bitter yam starch granules may be more associated to protein bodies (Otto et al 1997) than the other yam starches. Comparable protein contents of 0.28-2.89% (Odeku and Picker-Freyer 2007), 3.23% (Aprianita et al 2009) and 1.22-2.27% (Olayinka et al 2011) has been reported for yams, Australian D. alata, and red and white sorghum starches, respectively. All modifications significantly reduced crude protein of the native starches.…”

“…Postharvest losses of yams not treated with fungicides during storage could vary between 10-15% and 30-50% after three and six months, respectively (Opara 2003). Hence, production of starches from yams would help reduce wastage, enhance value addition, and revenue generation (Odeku and Picker-Freyer 2007). Due to the relatively high carbohydrate content, yam is considered as a source from which starch could be extracted for both household and industrial applications.…”

“…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.…”

“…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. Few available literature had focused on properties of native yam starches for tablet formation (Odeku and Picker-Freyer 2007;Zuluaga et al 2007), citric and ascorbic acid treatment of white yam flour (Akubor 2013), acid hydrolysis of water and white yam starches in disintegrant or excipient development (Odeku and Akinwande 2012), and c-irradiation of white and water yams (Falade et al 2011). Also, Falade and Ayetigbo (2015) had studied the effects of annealing, acid hydrolysis and lowcitric acid modifications on physical and functional properties of yam starches.…”