Extrusion processing of restructured peach and peach/starch gels

This study investigated the potential of twin screw extrusion technology to produce value-added, restructured peach and peach/starch gels. The effects of water content, melt temperature, sugar and starch concentration on prod uct color water activity and texture were determined. Water exhibited the g reatest effects. As water content increased, product color darkened signifi cantly, water activity increased, and hardness and springiness values decre ased significantly in both peach and peach/starch gels. Increasing melt tem peratures resulted in darker products. Significant interactions between wat er content and temperature were observed for 100% peach gels. Starch additi on resulted in significant increases in hardness, adhesiveness and cohesive ness values, as well as decreases in product springiness. Increasing melt t emperatures resulted in peach/starch gels with softer, more adhesive and co hesive textures. The addition of sugar to peach gels did not significantly affect their color; however, sugar addition did significantly increase the L, a and b values of peach/starch gels. Sugar concentration did not affect peach gel texture, but sugar and starch concentration interacted significan tly in peach/starch gels. As sugar concentration increased the effect of st arch concentration on the hardness and adhesiveness decreased. Polynomial r egression analysis was utilized to model the relationship between specific mechanical energy and product hardness. (C) 1999 Academic Press.