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Mannitol spoilage

Sorbitol and Mannitol. Sorbitol is present in fruits but not in grapes. A method for its determination is required to detect illegal blending of fruit wines with grape wines. Mannitol is produced by bacterial spoilage. Sorbitol dehydrogenase and thin-layer chromatography have been used for their simultaneous determination (5). [Pg.151]

Mannitol is derived from reduction of the Ci on mannose. In wine, it is produced by the reduction of the C2 on fructose by lactic bacteria. Mannitol is usually present in very small quantities. Higher concentrations are due to lactic bacteria or possibly Botrytis cinerea. Abnormally high concentrations indicate severe lactic spoilage. [Pg.57]

Besides acetic acid, lactic spoilage produces lactic acid and various secondary compounds that contribute to various olfactory defects. Some bacteria convert fructose into mannitol, explaining why this phenomenon used to be known as man-nitic fermentation. [Pg.239]

Mannitol salt formation is also used as a laboratory diagnostic test for the separation of homofermenters (which do not reduce fructose in formation of mannitol) from heterofermenters, which utilize the pathway described above. From the winemaker s perspective, the importance of mannitol formation, by itself, is uncertain except to increase the potential for acetic acid production. Sponholz (1993) reports that it is associated with bacterially mediated deterioration in high-pH sweet wines. He concludes that the best technique for the prevention is acidulation, whereby the pH is lowered to the point (<3.5) at which the likelihood of growth of most spoilage lactics is precluded. [Pg.36]

Mannitol. Whereas mannitic fermentations are seldom a problem where sulfur dioxide, pure yeasts, and temperature control are employed, Martucci (1941) has reported them in Argentina. He recommended control of the must acidity, since a high pH also favored such spoilage. A complicated polaiimetric procedure for mannitol (a sugar alcohol) in wines was presented by Salani (1937). Formation of mannite during dialysis of musts at low temperatures (8° to 10° C. (46.4° to 50° F.)) in the presence of chloroform was reported by Barbera (1933b) (possibly owing to enzyme action). [Pg.425]

Additional yeast spoilage is induced by species of the genera Candida Mycoderma), Pischia and Hansenula (Willia). Other microorganisms are involved in the formation of viscous, moldy and ropy wine flavor defects. Bacterial spoilage may involve acetic acid and lactic acid bacteria. In this case vinegar or lactic acid souring is detectable. It has usually been associated with mannitol fermentation which may result in considerable amounts of mannitol. [Pg.926]


See other pages where Mannitol spoilage is mentioned: [Pg.178]    [Pg.178]    [Pg.66]    [Pg.91]    [Pg.173]    [Pg.222]    [Pg.266]   
See also in sourсe #XX -- [ Pg.178 ]




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