Influences of different pectins on the emulsifying performance of conjugates formed between pectin and whey protein isolate.

The effects of different pectins on the conjugates formed between pectin and whey protein isolate (WPI) under the dry-heating condition (80 °C, 79% relative humidity) were investigated in this study. The different pectin samples were sugar beet pectin (SBP), high methyl-esterified citrus pectin (HMCP) and low methyl-esterified citrus pectin (LMCP). The covalent linkage between pectin and WPI was proved by SDS-PAGE. As the incubation time was prolonged, the degree of glycosylation (DG) of WPI-pectin conjugate gradually increased, but its solubility decreased gradually. The glycosylated speed between WPI and SBP was the fastest, while the DG between WPI and LMCP was the highest. Even so, the 24 h-incubated WPI-HMCP conjugate sample had the best emulsifying properties in all of the prepared conjugates. All the results revealed that the HMCP was the most suitable pectin sample for preparing the WPI-pectin conjugate with a superior emulsifying performance.