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 product color, water activity and texture were determined. Water exhibited the greatest effects. As water content increased, product color darkened significantly, water activity increased, and hardness and springiness values decreased significantly in both peach and peach/starch gels. Increasing melt temperatures resulted in darker products. Significant interactions between water content and temperature were observed for 100% peach gels. Starch addition resulted in significant increases in hardness, adhesiveness and cohesiveness values, as well as decreases in product springiness. Increasing melt temperatures resulted in peach/starch gels with softer, more adhesive and cohesive 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 significantly in peach/starch gels. As sugar concentration increased, the effect of starch concentration on the hardness and adhesiveness decreased. Polynomial regression analysis was utilized to model the relationship between specific mechanical energy and product hardness.