摘要:Freeze-dried coconut press cake powder (CPP),
43% w/w protein, was used to investigate the heat-induced gelation by heating
in rheometer to
75℃ in a wide range of pH values, from 4 to 9. Low strain oscillatory method
applied the measure visco-elastic propertieson 15% w/w CPP. The gel strength
was also assessed by a texture analyzer. SDS-PAGE electrophoresis was conducted
to identify the proteins evolved in the gel network structure and the gel
micro-structure was also evaluated. At low pH, the CPP proteins formed soft
(elastic modulus <100 Pa) particulate gels prone to syneresis, with
aggregate size of the order of 4.2 micrometers. In the alkaline region,
homogenous gels were induced by heating. Gel strength started to increase
dramatically from 64℃ to
67℃, for pH 9 and pH 8 respectively, reaching the maximum gel elastic modulus
over 1000 Pa at pH 9. The SDS-PAGE showed that the polypeptide sub-unities at
24, 32 - 34 and 53 kDa were the most prominent in gelation.