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Post by sk1dar00 on Sept 4, 2012 19:34:43 GMT
I always thought mushrooms were a good option as they don't taste sweet, but now I read that they are v ery high in mannitol and am thus apprehensive of them... The NUTTAB tables and some research papers I got from Monash University both give the precise mannitol content per 100g and it seems relatively high at just under 3%.. - But is mannitol as bad as sorbitol?
Does it breakdown into fructose like sorbitol and if not what does it break down into? Does anyone know?
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Post by Charlie Arnold on Sept 4, 2012 21:36:42 GMT
I don't know if it is as bad as sorbitol but I know Meg cannot tolerate anything sweetened by it. I know with FM you have to avoid the sugar alcohols (polyols).
Found this article in wikipedia if you google mannitol and certainly fructose is mentioned in the pathway to create mannitol so I would assume its breakdown would reverse this pathway and therefore yes, it could breakdown back to fructose I suppose. Not really anything I have questioned before as it is on the no list but now you have me interested so will read some more. Have pasted the main part of the article here, not everything on wikipedia is gospel though so need to read more. Alot of wikipedia can be edited by anything as Colormist on the HFI board has discovered.
Obtaining mannitol[edit] Industrial synthesisMannitol is commonly formed via the hydrogenation of fructose, which is formed from either starch or sugar. Although starch is cheaper than sucrose, the transformation of starch is much more complicated. Eventually, it yields a syrup containing about 42% fructose, 52% dextrose, and 6% maltose. Sucrose is simply hydrolyzed into an invert sugar syrup, which contains about 50% fructose. In both cases, the syrups are chromatographically purified to contain 90–95% fructose. The fructose is then hydrogenated over a nickel catalyst into mixture of isomers sorbitol and mannitol. Yield is typically 50%:50%, although slightly alkaline reaction conditions can slightly increase mannitol yields.[5]
[edit] Biological synthesesMannitol is one of the most abundant energy and carbon storage molecules in nature, produced by a plethora of organisms, including bacteria, yeasts, fungi, algae, lichens, and many plants.[6] Fermentation by microorganisms is a possible alternative to traditional industrial synthesis, producing much higher yields of mannitol, with minimal to no side products. A fructose to mannitol metabolic pathway, known as the mannitol cycle in fungi, has been discovered in a type of red algae (Caloglossa leprieurii), and it is highly possible that other microorganisms employ similar such pathways.[7] A class of lactic acid bacteria, labeled heterofermentive because of their multiple fermentation pathways, convert either three fructose molecules or two fructose and one glucose molecule into two mannitol molecules, and one molecule each of lactic acid, acetic acid, and carbon dioxide. Feedstock syrups containing medium to large concentrations of fructose (for example, cashew apple juice, containing 55% fructose: 45% glucose) can produce yields 200g mannitol/ liter feedstock. Further research is being conducted, studying ways to engineer even more efficient mannitol pathways in lactic acid bacteria, and also studying the use of other microorganism, such as yeast[6] and E. coli bacteria in mannitol productions. When food grade strains of any of the aforementioned microorganisms are used, the mannitol and the organism itself are directly applicable to food products, avoiding the need for careful separation of microorganism and mannitol crystals. Although this is a promising method, steps are needed to scale it up to industrially needed quantities.[7]
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Post by RichardHep on Jan 25, 2019 17:07:06 GMT
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