抄録
The aim of this study was to evaluate the nature of the protein in sugar beet pectin, with particular emphasis on determining whether the protein is linked to carbohydrate in an AGP-type structure, similar to gum arabic.
GPC-MALLS, coupled online to light scattering, refractive index and UV was used to determine the molecular weight and distribution. The contribution of ferulic acid to the UV response was quantified by monitoring the elution profile at three different wavelengths (214, 254 and 280 nm). The molecular weight for sugar beet pectin was found to be in the range of 4.7 to 5.8 x 105 with a mass recovery of 70-80%, indicating the presence of 20-30% hydrogel particles which cannot pass through 0.45μm filters. In an effort to improve the mass recovery it was found that treatment such as longer hydration times, high shear mixing, hydrolysis, and sonication increased the mass recovery by bringing the hydrogel materials into solution. Reproducible data was obtained with high shear mixing and therefore, it was concluded that the molecular weight of sugar beet pectin sample is ~ 1 x 106 when 100% mass recovery is obtained. Complete mass recovery was also achieved by enzymatic digestion using Viscozyme and filtration through small size filters which resulted in a drastic decrease in the molecular weight. There was only a small decrease in the molecular weight following protease digestion, which could be an indication of a covalent linkage between protein and carbohydrate moieties.
