Hydrolysis of starch granules

Srichuwong, S., Isono, N., Mishima, T., Hisamatsu, M. (2005). Structure of linterized starch is related to X-ray diffraction pattern and susceptibility to acid and enzyme hydrolysis of starch granules. Int. J. Biol Macromol, 57,115-121. 

As observed previously, starch has been largely utilized in blends and nanocomposites with a variety of reinforcements. Less known is the ability to use starch nanocrystals (StNs) as reinforcement in polymer matrices. StNs with dimensions of a few nanometers are formed from acid hydrolysis of starch granules. These starch crystals are mainly formed of crystalline amylose, as acid hydrolysis removes the amorphous domains comprised mostly of amylopectin [172, 173]. Such StN-reinforced nanocomposites were prepared with poly(fS-hydroxyoctanoate) (PHO)... 

The acid hydrolysis of starch granules from potato, waxy maize, and amylo-maize-7 was studied in different ratios of mixtures of two of the four alcohols, from 100/0 to 0/100% in 10% (v/v) intervals [53]. Again, a series of soluble limit dextrins was obtained in 48-72 hr of reaction. The average d.p. of the limit dextrins decreased as the content of the higher alcohol was increased. Plots of the d.p. of the limit dextrins vs. the ratio of each alcohol mixture produced curves that resembled titration curves, with different plateau regions in which the d.p. of the limit dextrins changed very slowly or not at all. These plateau regions were characteristic and dependent on the types of alcohols, the volume ratios of the two alcohols in the mixture, and the type of starch. It was proposed that the formation of... 

Oates, C. G. (1997). Towards and understanding of starch granule structure and hydrolysis. 

The structure of starch granules is of essential importance. Amoiphous zones of irradiated granules undergo hydrolysis prior to hydrolysis in their crystalline areas.104 Irradiation of granules of maize starch causes them to break along radial and concentric lines. An increase of dose makes the granules more crunchy. These... 

The susceptibility of starch granules to hydrolysis catalyzed by a-amylase can be quantified by following the degree and the manner in which erosion and corrosion take place. Most starch granules are first hydrolyzed superficially. Granules of some... 

After extensive acid-catalyzed hydrolysis, the crystallites of starch granules are detached. With mild attrition, the starch granules break into small particles.307 The size of the small-particle starch varies with the conditions of the acid hydrolysis ... 

Kimura and Robyt201 made a kinetic study of the hydrolysis of seven types of starch granules from normal maize, waxy maize, barley, tapioca, amylomaize-7, shoti and potato by R. nievus glucoamylase-I. The different types of starch granules had... 

ENZYMATIC HYDROLYSIS OF STARCH. Starch is a substance used for storing energy reserve in plants, where it is deposited in the form of starch granules. Starch may be noticed in fruit juice as a milky haze. This haze disappears when the juice is heated, but re-appears after it is cooled to less than 10°C. Like pectin, starch has a protective colloid effect on suspended particles and thus makes juice clarification more difficult. 

Sulfuric acid is a powerful esterification catalyst. It has been widely applied with mixtures of acetic acid and acetic anhydride to promote acetylations of numerous substances. Use of this catalyzed reaction for starch acetylation, however, has not risen to pre-eminence among starch acetylation methods as it has done among cellulose acetylations, although both reactions were discovered at the same time. The underdevelopment of this reaction in the starch field may be due to the following causes (1) sulfuric acid, a powerful acetylation catalyst, strongly catalyzes the hydrolysis of starch molecules and cannot be used for starch acetylations in the concentrations found most effective for cellulose reactions (2) most investigations of this reaction have been made on whole granules... 

---