welcome!
Poltronieri Palmiro
Wednesday, 02 July 2008 10:58 UTC
thank you for expressing interest in this scientific topic.
Evry contribution on the study of bioactivity, functionality, and effects on model systems or in vivo, clinical studies, are welcomed.
It may be of interest, for part of the audience, chemicals that do not originate from natural sources, as ashes and nanoparticles from garbage disposal.
However, I am involved in studies on food treatments, so the main aspect is the beneficial effects and the safety of new food formulas (increasing the amounts and daily intakes of compounds) and fruit or vegetable treatments (physical and chemical preservation, to extend the shelf-life).
thanks to everybody
Palmiro
Updated 03 July 2008 11:42 UTC
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Replies
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Hello Palmiro,
I am currently writing a story for NN about the raw food diet movement. This may be completely out of your field of expertise or interest, but I was hoping you would be able to answer a couple of questions for me. People who practice the raw food diet claim that cooking food above 112F (~44 deg C) destroys vitamins, proteins, nutrients, and enzymes necessary for digestion and that this can lead to disease and aging. I am almost certain that protein cannot be “destroyed” by the levels of heat applied during cooking, however, can changes in protein conformation affect the way that protein is digested? Are denatured proteins somehow less bio-available or less digestible?I was wondering if you have an opinion on these claims and/or can direct me to studies addressing their validity.
Thank you in advance for your help!
Anna
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Hello, Anna,
thank you for posting and sharing your interest with this group.
there are proteins that is better to denature and cook, i.e. egg white (it has antinutritional effects) or plant proteins (protease inhibitors of many different types that could block digestive proteases, or other antinutritional factors). this is utmostly necessary talking of potatoes or legumes. Other nutrients need to be freed in order to provide theri beneficial effects (in maize flour, vit. PP, “pellagra prevention” nicotinamide, is available only after treatment with alcaline water, as in tortillas. In the heavy heat treatment used for prolonging the shelf life of milk, lisine is 50% destroyed after 10 minutes at 140 degrees celsius. In the last meeting on Delivery of functionality in complex food system, in Amherst, a french group reported that UHT milk, and milk powders, exerts the activation of IgE and the occurrence of allergies, compared to individuals drinking fresh milk.
There are reccomandations for not overcook foods,
not to use high amount of water to not disperse the vitamins, taking in account not only the heat but also the freezing when talking of “vitamin content” reduction or destruction.
The main good practice in “Nutrition science” is the combination of protein sources, as pasta with cheese, bread with milk, tortillas and faba beans or peas, lentils, beans. Other interesting asepcts are the method used for cooking. For instance, the production of sous vide, meat broth or beef muscles cooked overnight at 70 degrees celsius, that do not changethe shape of the meat because the muscle fibers do not strech. Nowadays cooking may be done in different ways, I will not use so much of microwaves, but would prefer short cooking (Wok) either for meat or for vegetables.
I hope the answer was of interest and centered, byut it is important to know that some food are there to be eaten “fresh”, as lectuce, spinach, other ask for any kind of cooking, liver, for example. As for japanese food, I think it is a good example of how to combine raw and cooked foods. -
Thank you very much for your reply, Palmiro! Having read a lot about nutrition and bioavailability of nutrients and other compounds over the two weeks, I am very interested to see how this group develops. I look forward to reading more about this!
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