Transient heat transfer in a boiled potato: a study related to food process engineering

Abstract

This paper examines the transient heat transfer within a potato while it is being cooked in boiling water. For spherically shaped potatoes it has been shown that for most of the heating process the potato behaves as a homogenous conducting material whose temperature rise is satisfactorily described by Fourier's equation for transient conduction. Microscopic examination of the potato structure shows how, when its temperature rises above about 65°, the gelatinization and swelling of the starch granules cause mechanical disintegration of the tuber tissue. This process corresponds to the potato beginning to change from raw to cooked, and it also leads to a deviation from the theory of the ideal solid. It has been shown, for the variety of potato used, that for the center to cook before the outside overcooks the potato should have a maximum diameter of 40 mm.