Effect of Storage on Starch Content and Modification of Cassava Starch

Abstract

The effect of storage on yield and modification of starch using hydrochloric acid and acetic anhydride were studied. Yield of starch from fresh roots (24.4%) was significantly greater than yield (16,2%) from roots stored at room temperature for six days. On a dry weight basis the amount of starch in the roots decreased over a six day storage period. The proximate composition of cassava starch on dry weight basis was 0.24% ash, 0.13% fat, 0.49% protein, 0.15% crude fibre and 98.4% starch. The isolated starch was treated with different concentration of hydrochloric acid to produce acid thinned and dextrinized starches and different concentration of acetic anhydride to produce acetyl substituted starches. The alkali number of acid thinned and dextrinized starches increased with acid treatment while the viscosity decreased. The degree of substitution increased with the concentration of acetic anhydride used. The cold water solubility of the acid thinned and acetyl substituted starches were similar to that of native starches while the solubility of the dextrinized starches increased with the acid concentration. The viscosity of the acetyl substituted starches increased with the degree of substitution.

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

“…The LGC of the acid hydrolysed and low-citric acid substituted starches improved from 4% (native) to 2% (Table 2) across cultivars, except for bitter yam starch. Acid hydrolysed hybrid maize starch, corn starch, potato, rice, red bean and cassava starches showed improved gelling capacity over their unmodified counterparts Wang and Wang 2001;Osunsami et al 1989;Kim and Ahn 1996). In our study, native and tempered starches developed soft viscous gels at lower concentrations (2-4% w/v), which became progressively hard or very hard as concentration increased (10-20% w/v), while acid hydrolysis and low-citric acid-substitution enhanced formation of hard gels at the different concentrations (2-20% w/v) in all cultivars.…”

Comparative Studies on Some Physico-chemical, Thermal, Morphological, and Pasting Properties of Acid-thinned Jicama and Maize Starches

“…The retrogradation rate of acid-thinned starch gels increased as hydrolysis proceeded (Kang et al 1997). Acid modification increased solubility and gel strength and decreased the viscosity of starches (Kim and Ahn 1996;Osunsam et al 1989). According to Wang and Wang (2001), the behavior of acid-thinned starches is associated with the average chain length polymerization degree (PD).…”

“…4). According to diverse researchers, acid thinning increased the solubility of starches (Whistler and Daniels 1990;Kim and Ahn 1996;Osunsam et al 1989;Sandhu et al 2007). Kim and Ahn (1996) reported an increase in the solubility of red bean maize starches hydrolyzed with acid, attributed to the damaged structures of starch granules.…”

Composition, structure, physicochemical properties, and modifications of cassava starch

“…Chromatographic analysis showed that amylose and amylopectin was prepared by reacting starch with acetic anhydride in an alkaline849 solution. The acetylation increased the water solubility and paste clarity, decreased the 850 pasting viscosities and gelling ability, the glass transition and gelatinization temperatures, and851 improved the freeze-thaw stability(Aiyeleye, Akingbala, & Oguntimein, 1993; Agboola, 852 Akingbala, & Oguntimein, 1991a & 1991b;Moorthy, 1985;Osunsami et al, 1989). Dynamic 853 moduli (G' and G'') of starch paste (5%) were higher or lower than control, depending on the 854 specific starch genotypes used(Osundahunsi & Mueller, 2011).…”