Value addition of orange fruit wastes in the enzymatic production of xylooligosaccharides

Xylooligosaccharides (XOS) are sugar oligomers made up of xylose units with the chain length of 2 to 10 and are considered non-digestible food ingredients. It is mainly produced from xylan hydrolysis. XOS have a characteristic of prebiotic by promoting the growth of probiotic organisms. They have various physiological effects such as reducing cholesterol, maintaining the gastrointestinal health and improving the biological availability of calcium, animal feed, anti-cancerous. The production of XOS from agricultural residues offers great scope to the nutraceutical and pharmaceutical industries as the raw material is cheap and abundantly available. The driving force of this study was to produce XOS from the organic wastes such as orange fruit wastes. These wastes are rich in xylan which can be used as a renewable material for producing XOS. XOS can be obtained by chemical or enzymatic method, but due to the yield of toxic by-product, enzymatic production is preferred. In the enzymatic extraction method, acetic acid was used to prepare pellets from dried orange peels powder followed by xylanase enzyme degradation performed at 2, 4, 6 and 8 h. Samples containing XOS were chromatographed on HPLC system having a fluorescence detector (Ex320 nm, Em420 nm). The column used was Agilent C18 of length 250 mm and 4.6 mm internal diameter.   Key words: Xylooligosaccharide, xylobiose, xylotriose, prebiotic, xylan, enzymatic extraction, HPLC.