Purification of Xylitol Obtained by Fermentation of Corncob Hydrolysates
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- 作者：Beatriz Rivas ; Paolo Torre ; José ; Manuel Domí ; nguez ; Attilio Converti ; and Juan Carlos Parajó
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2006
- 出版时间：June 14, 2006
- 年：2006
- 卷：54
- 期：12
- 页码：4430 - 4435
- 全文大小：60K
- 年卷期：v.54,no.12(June 14, 2006)
- ISSN：1520-5118
文摘
Hydrolysates obtained by autohydrolysis-posthydrolysis of corncobs were detoxified with charcoal,concentrated, supplemented with nutrients, and fermented with Debaryomyces hansenii. After biomassremoval, the fermented media contained 0.1137 kg of nonvolatile components (NVC)/kg of liquor,which corresponded mainly to xylitol (0.6249 kg/kg of NVC) but also to minor amounts of inorganiccomponents (measured as ashes), proteins, nonfermented sugars (xylose and arabinose), uronicacids, arabitol, and other nonvolatile components (ONVC). The media were subjected to furtherprocessing (sequential stages of adsorption, concentration, ethanol precipitation, concentration, andcrystallization) to obtain food-grade xylitol. Adsorption experiments were carried out at various solid-to-liquor ratios. Under selected conditions (1 kg of charcoal/15 kg of liquors), the xylitol contentincreased to 0.6873 kg/kg of NVC, and almost total decoloration was achieved. The resulting liquorwas concentrated by evaporation to increase its NVC content to 0.4032 kg/kg of liquor (correspondingto a xylitol concentration of 0.280 kg/kg of liquor), and ethanol was added to precipitate a part of theNVC (mainly proteins, but also uronic acids, ashes, and other nonvolatile compounds). Refined liquors(containing 0.7303 kg of xylitol/kg of NVC) were concentrated again, and ethanol was added (toreach 40-60% volume of the stream) to allow crystallization at -10 or -5 
C. Under selectedconditions, 43.7% of xylitol contained in the initial fermentation broth was recovered in well-formed,homogeneous crystals, in which xylitol accounted for 98.9% of the total oven-dry weight. Materialbalances are presented for the whole processing scheme considered in this work.Keywords: Charcoal adsorption; crystallization; decoloration; ethanol precipitation; xylitol purification
C. Under selectedconditions, 43.7% of xylitol contained in the initial fermentation broth was recovered in well-formed,homogeneous crystals, in which xylitol accounted for 98.9% of the total oven-dry weight. Materialbalances are presented for the whole processing scheme considered in this work.Keywords: Charcoal adsorption; crystallization; decoloration; ethanol precipitation; xylitol purification