Porcine Pancreatic α-Amylase Hydrolysis of Native Starch Granules as a Function of Granule Surface Area

Abstract

Porcine pancreatic alpha-amylase activity on native starch granules is more accurately described as a function of surface area of the granules rather than of substrate concentration. The apparent K(m) of alpha-amylolysis of native starch from potato, maize, and rice expressed as a function of substrate concentration was largest for potato with a single value of V(max). However, the ratio of the slope of a Lineweaver-Burk plot to that of rice for enzymatic hydrolysis of native potato and maize starch were 7.78 and 2.58, respectively, which were very close to the ratio of surface area per mass of the two starch granules to that of rice. Therefore, the reciprocal of initial velocity was a linear function of the reciprocal of surface area for each starch granule. Surface area was calculated assuming the starch granules were spherical. The values obtained by this calculation were in good agreement with the value obtained by the photomicrographic method. By comparing enzymatic digestion of native maize granules to that of rice granules, it was concluded that the presence of pores in maize granules appeared to significantly affect overall rate of digestion after sufficient reaction time, but not at the very initial stage of hydrolysis.

Structure–function relationships in A and B granules from wheat starches of similar amylose content

“…The larger relative surface area of small granules is consistent with their greater initial digestibility by enzymes compared to the large granules. Similar findings were reported by Kong, Kim, Kim, and Kim (2003), who compared the rate of digestion of monodisperse maize (large granules) and rice starches (small granules). Moreover, we found a strong positive correlation between digestibility in the first hour and the proportion of short amylopectin chains, and a strong negative correlation between the digestibility at 0.5 h and the amount of medium length amylopectin chains.…”

Preferential and rapid degradation of raw rice starch by an α-amylase of glycoside hydrolase subfamily GH13_37

“…In both cases, the release of reducing sugar increased significantly with increasing starch concentration from 1 to 8 %, while the enzyme activity was slightly decreased in the presence of 12 % starch. Thus it appears that the enzymatic efficiency is highly dependent on the starch concentration, which is in good agreement with the previous study of classical porcine pancreatic α-amylase (Kong et al 2003).…”

Characterization of Normal and Waxy Corn Starch for Bioethanol Production

“…The amount of enzymes adsorbed to the granule surface is proportional to the surface area of the starch granule; as a result, the hydrolysis rate of starch is impacted by the granular surface area (Kong et al 2003). Starch with small granules (i.e.…”