Tapioca starch modification

For chemical modification, tapioca starch is easily modified to all current commercial derivatives. There are no special precautions or equipment required beyond what already might be practiced for a particular derivative or reagent applied to other starches. Recovery of modified products is facilitated in conventional washing and drying equipment. The reader is referred to Wurzburg47 and Chapter 17 for details of starch modifications, all of which may be practiced with tapioca starch. In the preparation and evaluation of some derivatives of tapioca starch, some of its unique characteristics have been revealed. 

As a native starch, lipids and protein residuals are significantly lower than they are in many other commercial starches. These properties of tapioca starch have been utilized in many industries and further enhanced by means of physical and/or chemical modifications which give close control of its properties to fit the needs of customers in process and product applications. However, tapioca starch is regarded as a specialty starch outside of its local production area. 

Tapioca starch and chemically modified tapioca starches are easily converted to instant (pregelatinized) forms (also known as cold-water-soluble starch). This physical modification is brought about by pasting of the starch and subsequent drying as described in Section 12.4. Control of particle size is critical to texture and rehydration rate when the product is redispersed in water.68 Fine particle size results in a smooth texture on redispersion, e.g. in pudding preparation.69 As a comparison, coarse texture could be more desirable in fruit- or vegetable-based foods. 

Acid modification of tapioca starch earlier reported to increase the mechanical strength of tablets. The development of ordered structure (double helices) of these starches was monitored using CP MAS NMR and X-ray diffraction. As the hydrolysis time increased, the intensity of the resonance for Cl and C4 amorphous fractions decreased while that for Cl and C4 double helix fractions increased. Relative crystallinity obtained from C CP MAS NMR and X-ray diffraction methods both increased sharply initially and then levelled off with hydrolysis time. The initial increase in relative double helix content and crystallinity was due to a hydrolytic destruction in the amorphous domain, retrogradation of the partially hydrolysed amylose and crystallisation of free amylopectin double helices. ... 

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