Starch retrograded

Another factor is the need for thinner viscosity binders. This puts a heavy demand on the water holding property of the starch. A retrograded starch will result from a non-derivative made to a low viscosity. Specialty starches are providing the properties needed... 

Native starch granules exhibit three main types of X-ray diffractogram. The A type is characteristic of most starches of cereal origin the B t5q)e of potato (Figure 8.3), other root and tuber starches, and amylomaize starches and retrograded starch the C type of smooth pea and various bean starches. 

Fredriksson, H., Bjork, L, Andersson, R., Liljeberg, H., Silverio, J., Eliasson, A. -C., Aman, P. (2000). Studies on a-amylase degradation of retrograded starch gels from waxy maize and high-amylopectin potato. Carbohydrate Polymers, 43, 81-87. 

Starches with high amylose content, such as corn starch (28% amylose) retrograde more than starches with lower amylose content, such as potato starch (20% amylose). Redispersion of retrograded starch is energy-intensive due to extensive bonding. Temperatures of 115° to 120°C are required to solubilize amylose gels or crystals. Amylopectin gels can be redispersed at temperatures above 55°C. 

In water, inulin undergoes reversion from a more soluble to a less soluble form, in the manner of retrograding starch (Whistler and Smart, 1953) it is slightly soluble in organic solvents. Fructans are easily hydrolyzed by acid. Levan is the branched isomer of inulin. 

Studies of dynamics in wet and dry carbohydrates have also been performed. Slow motions of polysaccharide chains in native starch and retrograding starch gels were monitored with two-dimensional 2H exchange and stimulated echo experiments.117 The effects of hydration on the dynamics of /j-cyclodextrin polymers have been examined with 13C T and H T p measurements,118 and WISE experiments were used to probe the effects of hydration on polysaccharide chains in maize starch forms A and B.119... 

It is significant that no V diagram is obtained with ungelatinized granules or with retrograded starch. Hence Bundle presumes that the... 

By using microwave irradiation, a suspension of starch (10%) in dilute hydrochloric acid (0.5 M) is completely hydrolyzed to glucose within 5 min without the formation of colored byproducts. The same suspension of starch heated at 100 ° C in sealed tubes was hydrolyzed to glucose after 60 min, but some retrograded starch still remained suspended in the solution. If the retrograded starch is isolated, resuspended in dilute hydrochloric acid and irradiated, it is completedy hydrolyzed after 5 min.97 In the presence of metal halides, complete hydrolysis was achieved in 2-3 min.98... 

Native A-starch occurs predominantly in cereal grains, B-starch is found in certain tuberous plants, C-starch is a rare form found in some plants and may actually be a combination of A- and B-starches. Partial conversion of B-starch to A-starch can be accomplished by adjusting temperature and humidity conditions, but complete conversion has never been achieved. When starch is dissolved in hot water, it spontaneously undergoes gelation and subsequent crystallization in the well-known process of retrogradation.(13) The polymorphic form of retrograded starch is B starch, irrespective of the form of starch initially dissolved. 

Kapelko M, Zi ha T, Golachowski A, Gryszkin A. Effect of the production method on the properties of RS3/RS4 type resistant starch. Part 1. Properties of retrograded starch (RS3) produced under various conditions and its susceptibility to acetylation. Pood Chem 2012 135 1494-1504. 

---