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Purification by ion-exchange chromatography of prebiotic oligosaccharides derived from lactose-isomerized whey permeate.
|Authors:||Sabater, Carlos ; Prodanov, M. ; Olano, Agustín ; Montilla, Antonia ; Corzo, Nieves|
|Abstract:||Whey permeate (WP) is a by-product obtained by ultrafiltration of cheese whey, lactose and salts being the main components. Today, one of the most promising uses of WP is the synthesis of prebiotic oligosaccharides for their potential use as functional ingredients. On the other hand, lactose is a reducing carbohydrate susceptible to be isomerized to lactulose. Among the different catalysts tested the highest yields (70-80%) are obtained using aluminates or borates. However, the main drawback of the use of these two catalysts is that they must be removed before used for human consumption. Therefore, the aim of this study was to develop a feasible method to purify isomerized whey permeate (IWP), treated with sodium borate as catalyst and selective ion-exchange resins to remove boron. Then, purified IWP was used to synthesize oligosaccharides derived from lactulose (OsLu) and from lactose (galacto-oligosaccharides, GOS). WP (lactose 200 mg/mL) isomerization was performed with sodium borate (molar ratio boron/lactose 1:1) at pH 12, 70 ºC for 10-180 min. Boron was retained from the IWP using the combination of a strong acid (IR-120) and a weak base (IRA-743) anion-exchange resins. The elimination of boron was followed by HPLC-SEC, VIS-spectrophotometry (Azomethine H method) and ICP-MS analysis. Finally, transgalactosylation reactions were performed using β-galactosidase from Bacillus circulans with WP and IWP with different molar ratios of lactose:lactulose as substrate. The analysis of carbohydrates was carried out by GC-FID. According to the results obtained, formation of lactulose with yields >71% was achieved after 20 and 30 min of reaction. Treatment with resins IR-120 and IRA-743, gave rise to purified IWP (99.98% boron elimination), without loss of lactulose. In the transglycosylation reactions maximum formation (75-80% total carbohydrates) of prebiotic compounds (lactulose, GOS and OsLu) was obtained after 3 h with purified IWP (ratio lactose:lactulose 1:2.4).|
|Description:||Resumen del póster presentado a la XV Reunión Científica Sociedad Española de Cromatografía y Técnicas Afines (SECyTA) y VII Reunión Nacional Sociedad Española de Espectrometría de Masas (SEEM), celebradas en castellón del 27 al 30 de octubre de 2015.|
|Appears in Collections:||(CIAL) Comunicaciones congresos|