Wheat retrogradation

Behzadi, G., Kalen, P., Parvopassu, R Wiklund, L. (1990). Afferents to the median raphe nucleus of the rat retrograde cholera toxin and wheat germ conjugated horseradish peroxidase tracing, and selective D-[3H]aspartate labelling of possible excitatory amino acid inputs. Neuroscience 37, 77-100. 

Shipley MT Transport of molecules from nose to brain transneuronal anterograde and retrograde labeling in the rat olfactory system by wheat germ agglutinin-horseradish peroxidase applied to the nasal epithelium. Brain Res Bull 15 129-142, 1985... 

Figure 8.16 Effect of moisture content on retrogradation kinetics of starch in starch gels or bread 1 wheat starch gels stored at 4°C for 14 days 175 2, 3 and 4 correspond to wheat starch gels, bread and bread with 0.5% monoglyceride, respectively, stored at 25°C for seven days.178...

Figure 14.3 Retrogradation of rye starch (O, , I) maize starch ( ) and wheat starch ( ). (From reference 8, used with permission)...

Englyst et al.248 classified starch into three types RSI, RS2 and RS3. RSI is a starch protected from digestion in the small intestine by a food matrix, such as the intact endosperm of a wheat kernel. RS2 is simply unswollen granular starch. RS3 is starch that was gelatinized, but then retrograded to become enzyme-resistant. Chemically modified (e.g. crosslinked) starch (RS4) has been added to the list.242 The four forms of resistant starch and their measurement are described by Nugent246 and Sajilata et al.249... 

Both processes use starch (com, potato, rice, wheat, etc.) as the substrate. Com and potato starches are most commonly used. In both processes, the starch is hydrolyzed to a dextrose equivalent (DE) of 3 to 8 (see Chapter 21) prior to use.25 If liqui-faction/hydrolysis is not sufficient, retrogradation occurs. This limits the availability of substrate, resulting in low yields of cyclodextrins, and interferes with later recovery steps. If the starch is over-hydrolyzed, the disproportionation reaction dominates and yields of cyclodextrins are low. If an a-amylase is used to hydrolyze the starch, it must be inactivated by acidification, raising the temperature, otherwise, the yield will be greatly reduced. 

Cairns, P., I Anson, K. J., and Morris, V. J. (1991). The effect of added sugars on the retrogradation of wheat starch gels by X-ray diffraction. Food Hydrocoil. 5 151-153. 

In this survey, gelation is considered as a rapid and random association of linear molecules, while retrogradation is comparatively slow and crystalline. The differentiation is an arbitrary one, since the same forces are responsible. Thus corn and wheat starches are prone to retrograde as compared with tapioca and potato, while waxy maize is completely stable. 

Shipley MT, Adamek GD. 1984. The connections ofthe mouse olfactory bulb A study using orthogradc and retrograde transport of wheat germ agglutinin conjugated to horseradish peroxidase. Brain Res Bull 12 669-688. 

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