Hydrocolloid from leaves of Corchorus olitorius and its synergistic effect on κ-carrageenan gel strength

Hydrocolloid from leaves of Corchorus olitorius was fractionated with ammonium sulfate (50%, w/v) and extracted with distilled water. The yield of the hydrocolloid was 6.0% (w/w) based on dry material. The contents of total carbohydrate, anhydrouronic acid, ash, protein, and moisture of the hydrocolloids were 62.2%, 35.3%, 13.3%, 5.5%, and 16.1% (w/w), respectively. Degree of esterification of 19.4% was calculated assuming that the methoxyl groups were attached to only anhydrouronic acid. When the molecular weight distribution was checked by size-exclusion chromatography on Sepharose CL-4B, the hydrocolloid gave a single peak with a molecular weight of 1860 kDa. The rheological behavior of mixed gels made from κ-carrageenan and the hydrocolloid at a total hydrocolloids concentration of 1% (w/w) was investigated by gel strength measurement. Then it was found that the hydrocolloid exhibited synergy with κ-carrageenan in relation to gel strength.