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Author Topic: What causes a bitter after-taste following consumption of old potatoes?  (Read 10550 times)

Offline DanielV

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Hello all,

Last night I roasted some potatoes that were starting to sprout and were not as firm as an ideal potato.  I have done this thousands of times and have had no problems.  But since eating dinner last night (about 18 hours ago) I have the most disgusting/revolting/awful aftertaste in my mouth.

Does any one have any explanations around the science of why this has happened?



« Last Edit: 16/12/2009 19:56:35 by chris »


Offline RD

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Potatoes are such a common feature of the Western diet that most people are surprised to learn that they are the produce of a poisonous plant. In fact potato stems and leaves contain a series of alkaloidal glycosides, termed solanines, which are highly toxic. The normal tuber contains only small amounts of solanines in the peel and none in the flesh. Poisoning due to feeding the leaves and stems to domestic animals is well recognised, and one instance of poisoning in man was traced to the use of leaves and young shoots as a boiled green vegetable.' The main hazard, however, comes from eating "greened" potatoes. Greening and sprouting occur when potato tubers are exposed to light or are stored in adverse conditions, and these processes are associated with the production of the alkaloids. Initially this occurs at the sites of increased metabolic activity, such as the "eyes"; but eventually solanines can be detected in the flesh of the tuber, and the normal, high concentration-gradient between the peel and the flesh is lost. Fortunately, few people cook greened or sprouted potatoes because of their appearance and their bitter, unpleasant taste
« Last Edit: 13/12/2009 11:24:32 by RD »

Offline Bored chemist

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At least most of the flavour of those 4 is due to things other than alkaloids. The caffeine and related compounds in tea, coffe and chocolate are alkaloids but don't add a lot to the taste. I don't think that there are any significant alkaloids in vanilla. Also, not all bitter materials in plants are alkaloids.
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