Control of resistant starch content of cookie by pre-dehydration treatment

It is known that crystalline amylopectin of starch plays a role of resistant starch. Although crystalline amylopectin of starchy food melts almost completely during its heat-processing, the melting may be prevented by a pre-dehydration treatment, because melting temperature of the crystalline amylopectin increases with a decrease in the water content of starch. In order to some insight into the concept, effect of the pre-dehydration treatment on the melting temperature of crystalline amylopectin in cookie dough and the resistant starch content of cookie was investigated. Cookie dough was prepared according to a common cooking text, and vacuumed at a condition. The cookie dough samples dehydrated for 0 h and 6 h were employed typically for following studies. Melting temperature of the crystalline amylopectin in the cookie dough samples was investigated by using a differential scanning calorimetry. It was confirmed that the melting temperature of the dehydrated sample was higher than non-dehydrated one. On the other hand, the cookie dough samples were baked at a condition, and resistant starch content of the cookie sample was investigated according to a previous study. It was found that resistant starch content of the pre-dehydrated sample was higher than non-dehydrated one. From these results, it was suggested that the melting temperature of crystalline amylopectin in the cookie dough increased by the pre-dehydration treatment, and the melting of crystalline amylopectin was prevented partially during its heat-processing.