Physicochemical Changes in Potato Granules During Storage

Physicochemical properties of freeze-thaw (F-T) and add-back (A-B) potato granules, such as swelling power (SP), water-holding capacity (WHC), degree of starch retrogradation, moisture change, and rate of rehydration were monitored over about 100 wk of storage. SP of both types of granules decreased to minima after 40 wk then increased on further storage, while WHC showed an opposite trend, reaching maxima after 52 wk. Degree of starch retrogradation in the granules increased to maxima after 40 wk then declined. Moisture content of the granules also increased slightly during the first 33 wk then decreased on further storage. These changes caused the reduction in the rehydration rate of the granules from 8.3 × 10^?2 see^?1 to 5.5 × 10^?2 set^?1 (F-T) and 5.2 × 10^?2 sec^?1 (A-B) after 36 wk of storage, after which the rate again increased. Addition of Ca⁺⁺ to the granules during precooking and cooling steps of the process appeared to cause similar changes.