Effects of boiling, warm-holding, mashing and cooling on the levels of enzyme-resistant potato starch

The effects of boiling, warm-holding, cooling and mashing on the enzyme-resistant starch (ERS) content of potatoes was studied together with inter-tuber and inter-cultivar variation in ERS content. Inter-tuber variation in ERS content was small and mean values (on a dry matter basis) for boiled and raw potatoes were 10.7 and 74.2% (cultivar Rooster) and 10.8 and 74.3% (cultivar Anna). There was no significant difference between the ERS values of boiled potatoes of seven cultivars (range 10.0-10.8%). Warm-holding mashed potatoes at 65-70 degrees C for 1 hr raised ERS values from 2.20 to 4.80%. In a separate test slow cooling over 2 hr to 21 degrees C raised the ERS content from 3.65 to 6.35%. Multiple cook-cool (3X) gave ERS contents of 23.2 and 18.2% for boiled potatoes held for 24 hr at 4 or 20 degrees C. Mashing and freezing raised ERS values by 1-2%.