Abstract:

Two hemicellulose B fractions HCLB-1 and HCLB-2 were purified by DEAE-Sepharose Fast Flow column chromatography from soybean dregs dietary fibers prepared in our lab and their respective aqueous solutions at 10 mg/mL were treated with the technique of dynamic high pressure microfluidization (DHPM) at varying pressures. Untreated and treated HCLB-1 and HCLB-2 were tested for their molecular weight distribution and functional groups. The results showed that DHPM treatment had an obvious effect on the molecular weight distribution of HCLB-1and HCLB-2. The molecular weight distribution of treated HCLB-1 exhibited 910, 177 kD and 62 kD molecular weight peaks. An 813 kD molecular weight peak was found in the molecular weight distribution of treated HCLB-2. DHPM treatment resulted in red shift/blue shift of characteristic absorption peaks of functional groups in HCLB-1or HCLB-2 observed from their FT-IR spectra. The O－H stretching vibration appearing at 3416 cm-1 in HCLB-1 and the stretching vibration at 1058 cm-1 representing ether linkage presented blue shift to 3405  cm-1 and 1048 cm-1, respectively, while the C－H stretching vibration a red shift from 2923 to 2928 cm-1 after DHPM treatment. Also, there were red shit from 1413 to 1417 cm-1 and blue shift from 1377 to 1369 cm-1. However, the respective characteristic absorption peaks of water andβ-glycosidic linkage kept unchanged basically. The changes in the FT-IR spectral characteristics of HCLB-2 were similar to those in the FT-IR spectral characteristics of HCLB-2.

Key words: dynamic high pressure microfluidization (DHPM), hemicellulose B, molecular weight distribution, functional group