Inter-laboratory analysis of cereal beta-glucan extracts of nutritional importance: An evaluation of different methods for determining weight-average molecular weight and molecular weight distribution
نویسندگان
چکیده
In an interlaboratory study we compare different methods to determine the weight-average molecular weight (Mw) and distribution of six cereal beta-glucan isolates nutritional importance. Size-exclusion chromatography (SEC) with multi-angle light scattering (MALS), capillary viscometry, sedimentation velocity analytical ultracentrifugation one asymmetric flow field-flow fractionation (AF4)-MALS method all yielded similar Mw values for mostly individual chains dissolved molecules. SEC post-column calcofluor detection underestimated >500 × 103 g/mol. The molecules analysed by these were primarily in a random coil conformation as evidenced from Mark-Houwink-Kuhn-Sakurada (MHKS) scaling coefficients between 0.5 0.6 Wales-Van Holde ratios 1.4 1.7. contrast, second AF4-MALS much larger same samples indicating presence aggregates. Storage solutions dark at 4 °C years revealed them be stable. This suggests absence storage-induced irreversible aggregation phenomena or chain-scission. Shear forces viscometer hydrostatic pressure probably led reversable dissociation aggregates into molecularly species. Thus, yield true not biased was case AF4 based employed.
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ژورنال
عنوان ژورنال: Food Hydrocolloids
سال: 2022
ISSN: ['1873-7137', '0268-005X']
DOI: https://doi.org/10.1016/j.foodhyd.2022.107510