EFFECT OF ULTRASOUND ON THE IMMUNOGENIC CORN COB XYLAN

Changes in the structural, molecular and functional properties of the immunogenic corn cob xylan evoked by ultrasonication in water, 1% NaOH and 5% NaOH were investigated. The reduction of the high molar mass ( MM) fraction was more intense than that of the medium MM fraction, dep ending on the sonic power, sonication time, and alkali concentration. The chain degradation was more effective in the alkaline media. The UV -absorbing component, accompanying the xylan polymers in the whole MM range, showed an accumulation in the high MM region as well as shiften ing to higher sizes, particularly in 5% NaOH. The sugar composition an d primary structure of the xylan was almost retained under all irradia tion conditions studied. Although the biological activity of the xylan was affected by the ultrasound, no significant decrease of the biolog ical response was found at short irradiation time and low sonic power. (C) 1997 Elsevier Science B.V.