The following became clear after the comparison of potatoes both cooked with pressure pan and steamer.
Cooking condition of pressure pan to attain the core of potatoes (150g) to the same hardness as that cooked with steamer was 5 min. for heating until steam leak and continuously heating for 3 min, and further intact holding for 5 min.
Although the hardness of potato core became almost the same, the exterior of potato with pressure pan became overtender.
Mushed potato made from the potato cooked with pressure pan was more sticky and harder than that with steamer. In the case of mushed potato with pressure pan, tissue were partially destructed and the amount of gelatinized starch which flowed out from tissue and the amount of soluble pectin were greater than the case of that with steamer.
When cooking time was prolonged for 2 min, those tendency became more clearly.
Both the consumption of gas and time required for cooking, in case of pressure pan, decreased by apporoximately one-half in quantity of those of those of steamer.