THE EFFECTS OF A XYLANASE AND A BETA-GLUCANASE FROM TRICHODERMA-REESEI ON THE NONSTARCH POLYSACCHARIDES OF WHOLE MEAL RYE SLURRY

The effects of extraction conditions (pH, temperature, enzymic treatme nt) on the extractability of rye meal non-starch polysaccharides were studied. The yield of pentosans and extractable matter increased with increases in both temperature and pH during extraction. The extract vi scosity was correlated closely with the pentosan content of the extrac t. The molecular size of the extracted nonstarch polysaccharides decre ased as the extract pH decreased. Enzymic treatment during extraction increased the amount of pentosan solubilised. Xylanases almost doubled the amount of extractable pentosans, but these were degraded to oligo saccharides. With beta-glucanase and protease, the pentosan content of the extract increased by 65% and 40%, respectively. In addition, the beta-glucan extractability was increased with protease by 10% and with beta-glucanase by 90%. Using size-exclusion HPLC it was observed that the molecular size of extractable rye beta-glucans was lower than tha t of the extractable rye pentosans. beta-Glucanase caused considerable hydrolysis of beta-glucan and no more beta-glucan could be detected b y size-exclusion HPLC. Protease treatment decreased the molecular size of extractable beta-glucan. All enzymatic treatments caused a disrupt ion of the endosperm cell walls in the extract residue.