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ABSTRACT Corn husks are the major wastes of corn industries with meagre economic significance. The present study was planned for value addition of corn husk through extraction of xylan, followed by its enzymatic hydrolysis into xylooligosaccharides, a pentose based prebiotic. Compositional analysis of corn husks revealed neutral detergent fibre 68.87%, acid detergent fibre 31.48%, hemicelluloses 37.39%, cellulose 29.07% and crude protein 2.68%. Irrespective of the extraction conditions, sodium hydroxide was found to be more effective in maximizing the yield of xylan from corn husks than potassium hydroxide (84% vs. 66%). Application of xylanase over the xylan of corn husks resulted into production of xylooligosaccharides with different degree of polymerization namely, xylobiose and xylotriose in addition to xylose monomer. On the basis of response surface model analysis, the maximum yield of xylobiose (1.9 mg/ml) was achieved with the enzymatic hydrolysis conditions of pH 5.8, temperature 44°C, enzyme dose 5.7U/ml and hydrolysis time of 17.5h. Therefore, the corn husks could be used as raw material for xylan extraction vis a vis its translation into prebiotic xylooligosaccharides.

Abstract Shochu is the most widely consumed spirit in Japan. In its manufacture is used koji, a solid fungus culture traditional of the Asian countries, but that makes the production process slow. Shochu can be produced from a variety of starchy sources, including sweet potato. About 7% of the world’s sweet potato production is wasted due to imperfections that make it unsuitable for consumption. However, this material can be used in ethanol production. Considering the high productivity of sweet potato in Brazil, an opportunity to add value to this raw material is perceived. An alternative process for the production of sweet potato distillate similar to shochu was proposed. Koji was replaced by a mixture of alpha-amylase and glucoamylase. Process time was reduced from 14 to only 1 day. Composition analyses were performed by HPLC and GC. The experimental yield of alcoholic fermentation using pectinase enzyme reached 67.31-73.65%, but methanol was above the limits of the legislation. Without the addition of pectinase, no methanol was formed. However, there was a decrease in yield (51.65-54.75%), due to the incomplete disintegration of sweet potatoes. The distillate produced and the commercial shochu presented the same absorption bands in FTIR analysis, identifying the similarity between them.

ABSTRACT Corn husks are the major wastes of corn industries with meagre economic significance. The present study was planned for value addition of corn husk through extraction of xylan, followed by its enzymatic hydrolysis into xylooligosaccharides, a pentose based prebiotic. Compositional analysis of corn husks revealed neutral detergent fibre 68.87%, acid detergent fibre 31.48%, hemicelluloses 37.39%, cellulose 29.07% and crude protein 2.68%. Irrespective of the extraction conditions, sodium hydroxide was found to be more effective in maximizing the yield of xylan from corn husks than potassium hydroxide (84% vs. 66%). Application of xylanase over the xylan of corn husks resulted into production of xylooligosaccharides with different degree of polymerization namely, xylobiose and xylotriose in addition to xylose monomer. On the basis of response surface model analysis, the maximum yield of xylobiose (1.9 mg/ml) was achieved with the enzymatic hydrolysis conditions of pH 5.8, temperature 44°C, enzyme dose 5.7U/ml and hydrolysis time of 17.5h. Therefore, the corn husks could be used as raw material for xylan extraction vis a vis its translation into prebiotic xylooligosaccharides.