Process for the preparation of surface active agents using wheat by-products and their applications

A process for preparing a surface active agent wherein wheat bran, wheat fibre or wheat straw is brought into contact with an aqueous acid solution at a temperature of between 20.degree. and 150.degree. C. for at least 5 seconds in order to obtain an aqueous pentose syrup and solid pulp, separating the solid pulp from the aqueous pentose syrup, the latter having a concentration of 30 to 95% by weight of pentoses, contacting the aqueous pentose syrup with an alcohol of the formula R.sup.2 OH in which R.sup.2 is a linear alkyl radical having from 1 to 5 carbon atoms at a temperature of between 20.degree. and 150.degree. C. to form a solution of lower alkyl (C.sub.1 -C.sub.5) pentosides, contacting the solution of lower alkyl (C.sub.1 -C.sub.5) pentosides with an alcohol of the formula R.sup.1 OH in which R.sup.1 is a branched or linear alkyl radical having from 6 to 22 carbon atoms at a temperature of between 20.degree. and 150.degree. C. to form a solution of surface active pentosides, and separating the surface active pentosides from the solution.