The Effect of Additives and Temperature on the Velocity of Hydrolysis of Raw Starch with Human Salivary  - amylase

Abstract

Aim: The research was carried out to determine the effect of increasing concentration of calcium chloride at different temperatures and a mixture of aqueous ethanol and calcium chloride at 37°C on the activity of human salivary a – amylase (HSaA) and to characterize the effects of the additives (co – solutes) separately, and as a mixture, in terms of activation and thermodynamic parameters. Study Design: Experimental. Place and Duration: Research Division of Ude International Concepts Limited (RC 862217) B. B. Agbor and Owa Sec Sch, Owa Oyibu, Delta, Nigeria. The research spanned a period of six months. Methodology: Bernfeld method of enzyme assay was used. Controls were free from additives while the experimental tests reaction mixture contained either a single additive or a mixture of additives. The additives are different sources of ethanol and calcium chloride. Results: The values of Gibbs free energy of activation (DG#), are 75.90±0.14 kJ/mol, and 77.28±0.15 kJ/mol, in the absence and presence of the salt respectively. The enthalpies of hydrolysis of the starch are 20.18±0.27 kJ/mol and 9.58±0.35 kJ/mol in the presence and absence of the salt respectively. The positive m – value ((113±3)´104 J/mol.M) being lower in the presence of local gin (LG) in the reaction mixture than m – value ((121.5±0.05)´104 J/mol.M) in the presence of Lord’s dry gin (BG), implies that LG is a stronger alcoholic beverage than BG. Conclusion: The increase in activation parameter resulted in a decrease in activity due to extra stabilizing effect of excess calcium ion. The hydrolysis of starch is enthalpically driven in the absence of the salt, while entropic factor is the case in the presence of the salt. The presence of calcium chloride opposed the inhibiting effect of lower concentration (« 90% (V/V)) of ethanol.