Production of bio-based fiber gums from the waste streams resulting from the commercial processing of corn bran and oat hulls

摘要

The U.S. food and non-food industries would benefit from domestically produced crude, semi-pure and pure bio-based fiber gums from corn bran and oat hulls. Corn bran and oat hulls are processed to produce commercial cellulose enriched fiber gels, which generate an alkaline waste stream containing many valuable and functional components, including bio-based fiber gums. In this study, the corn bran and oat hulls processing waste streams were concentrated and drum or spray dried to produce solid products, called crude bio-based fiber gum (crude BFG). Alternatively semi-pure products (semi-pure BFG) were prepared by ethanol precipitation of the concentrated waste stream. Semi-pure product was also produced by purification of the original unconcentrated waste stream using 10, 50 and 100 kDa MWCO ultrafiltration membranes. A highly pure BFG was prepared from the unconcentrated waste stream by first adjusting its pH to 4, removing the precipitated material and precipitating the resulting supernatant with two times its volume with ethanol. All four kinds of BFGs contain arabinoxylan but with different levels of purity. The arabinoxylans have a typical structure with a slight variation in Ara/Xyl ratio showing some differences in their branching. There is a big variation in their weight average molar mass (Mw) (33-386 kDa) due to variation in the processing conditions of the waste streams. Arabinoxylans are good emulsifiers for oil-in-water emulsion systems and binding agents for petroleum coke pellets and briquettes. They are also useful antioxidants and soluble dietary fibers with antioxidant activities showing a great potential for their applications in both food and non-food industries. Published by Elsevier Ltd.