ISSN:
1871-4528
Keywords:
softness
;
mealiness
;
water potential
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary It has been disputed whether, when potato starch gelatinises and absorbs water, it generates an osmotic or matric pressure that makes the potato cells become round and separate from one another. Starch suspensions heated at 100°C in dialysis bags absorbed water, suggesting that starch swelling pressure does exist. It was quantified by heating starch suspensions at 85°C in a chamber which absorbed water through a membrane and contained an argon bubble whose volume was measured. This gave starch swelling pressures around 100 kPa, increasing non-linearly with starch concentration. A comparable estimate (a few hundred kPa) of starch swelling pressure within cooked potato tissue was obtained from the fact that it largely prevented the tissue contraction expected due to loss of turgor pressure in the first 1.5 min of boiling. A slight expansion thereafter was attributed to the combined effect of starch swelling pressure and cell wall and middle lamella degradation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02357730
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