Production and purification of xylooligossaccharides from sugarcane bagasse and antioxidant potential assessment for functional ingredient application in the food industry

Xylooligosaccharides (XOS) are a type of prebiotic non-digestible carbohydrate obtained from lignocellulosic biomass through the enzymatic hydrolysis of hemicellulose; a raw material that is generated as a by-product of activity in the agro-industrial sector. As the most representative of lignocellulosic materials, sugarcane bagasse (SB) is a source for XOS production. Owing to the high impurity XOS content produced by direct enzymatic hydrolysis of xylan extracted from SB, subsequent refining steps (clarification and purification) are essential for food-related applications. This study aimed to investigate the XOS production process using enzymatic hydrolysis of xylan. Additionally, a refining step using active carbon during the XOS process was also applied; and the evaluation of the impacts the process may have on XOS antioxidant activity for potential application in food products. Xylan extraction was evaluated with potassium hydroxide (KOH) in the concentration range of 5-18 %, achieving a xylan extraction efficiency (E) up to 85 %, under hydrothermal conditions, and using 12 % hydroxide concentration for 45 min. The enzymatic hydrolysis reaction was performed by applying an endo-1,4-xylanase (NS50030-Novozymes (R)) cocktail, and 4.5 g/L of substrate with prebiotic fractions (xylobiose and xylotriose) as the major products, with a conversion yield of 260.82 g XOS/Kg xylan. The desorption was systematically investigated after evaluating of the ethanol elution concentration, and achieved up to 45 % of XOS recuperation in the translucent solution from 40 % ethanol eluate (v/v); demonstrating a high potential for use as a functional ingredient in food applications.