Processing by steam jet cooking

A significant discovery was made in the 1990s when a mixture of soy oil and com starch was passed through an excess steam jet cooker. The resulting starch dispersion contained soy oil droplets about 1 to 10 xm in diameter and the droplets did not coalesce with time, even after prolonged storage (Fanta and Eskins, 1995). The stability and lack of coalescence of the oil droplets in both hqnid dispersions and dried sohds was demonstrated, suggesting a specific starch-oil interaction (Knntson et al., 1996). Dickinson (1988) proposed that starch separates from water solntion and adsorbs onto the hydrophobic surfaces of oil droplets because water is a thermodynamically poor solvent for starch, and the adsorption of starch at the lipid-water interface leads to a redaction in the interfacial tension of the two-phase aqueous oil system. 

In this chapter, a number of non-traditional processing methods that have been developed to modify starch properties for a wide variety of end-use applications have been reviewed. For example, annealing and heat-moisture treatment have been shown to modify the swelling 

Extrusion is a rapid and continuous method for preparing new starch products and derivatives. There is interest in these materials because of the low cost of starch, the desirability of replacing petroleum-based materials with renewable feedstocks, the improved biodegradability of starch-based materials, and the creation of new markets for agricultural commodities. Steam jet cooking has been used to prepare stable starch-oil composites useful in food products and as water-based lubricants. Spherulites that could have practical end-use applications have also been prepared. 

Future years should see an increase in the use of these new processing techniques and other non-traditional methods of processing will also be developed. The current interest in biodegradability and the replacanent of petrochemical-based materials with agricultural products will result in inCTeased research on starch as a starling material for new products. 

Akdogan H. 1999. High moisture food extrusion. Int J Food Sci Technol 34 195-207. 

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