Effect of pH on the physicochemical and binder properties of tigernut starch

Abstract

Tigernut starch is starch extracted from the tubers of Cyperus esculentus L. a perennial herb commonly known as tigernut. The effect of pH on the foaming, gelatinization, solubility, swelling, paste clarity, viscosity, freeze–thaw stability, and binder efficiency of the starch in buffer solutions of pHs 4, 7, and 9.2, representative of acid, neutral, and alkaline pHs were evaluated. Marked pH responsiveness was observed in all these parameters to varying degrees. The foaming capacity, paste clarity, freeze–thaw stability, swelling, and viscosity increased while only the gelatinization temperature decreased with increasing pH. The pastes obtained at pHs 4 and 7 showed marked instability by forming a mass of hard coarse gel with the first freeze–thaw cycle while the paste of pH 9.2 maintained its normal viscoelastic‐gel texture even after the fourth freeze–thaw cycle. The properties of the ascorbic acid granules and tablets produced by wet granulation, using the pastes as binder showed pH‐responsiveness, with the granule formed with the paste of pH 9.2 showing higher mechanical strength and lower disintegration time. This study thus shows the diversity in the physicochemical and binder properties of tigernut starch with changes in pH.

Efficient processing of cassava starch: physicochemical characterization at different processing parameters

“…The lowest solubility of cassava starch shown by deionized water compared to tap water and mineral water (Table 3) could be due to its lowest pH value (Table 1) that limits partial starch gelatinization, hence reduces swelling power and solubility of starch, unlike at higher pH (Adebowale and Lawal, 2005). This result opposed the finding reported by Builders et al (2014), which stated that a pH condition which is higher than 7 reduces the solubility of tiger nut starch. The highest solubility of cassava starch treated with mineral water may indicate weakest bonding forces within starch granules (Aryee et al, 2006) compared to the cassava starch samples treated with other types of water and commercial starch.…”

Physicochemical properties of starch obtained from Curcuma karnatakensis - A new botanical source for high amylose content

“…The pH of the starch of sample A was 7.6, while that of sample B was 7.5 ( Table 1). The pH variation can alter the physicochemical properties of native starches and can impart new functionality (Builders et al, 2014).…”

Reduction of gelatinization temperatures of starch blend suspensions with supercritical CO2 treatment

“…On the other hand, the exposure of inner hydrophobic surface to water and dislocation of polymer chains has also been reported to occur for the effect of partial hydrolysis of starch in acidic and alkaline solutions [22]. Builders et al [23] found that the gelatinization temperature is remarkably sensitive to pH in the gelatinization of tigernut starch. In contrast, Simonin et al [24] found that pH does not have strong effect on gelatinization of waxy starches, but that pH has a small and significant (p < 0.05) effect on gelatinization of those starches under pressure.…”