Thermal and rheological properties of tapioca starch and xyloglucan mixtures in the presence of sucrose

The influence of sucrose on thermal and rheological properties of tapioca starch (TS)–tamarind seed xyloglucan (XG) mixtures was investigated. Rapid visco-analysis profiles of 5% w/w TS/XG dispersions at different mixing ratios revealed that peak and final viscosities increased with increasing sucrose and XG contents. Loss tangent of each mixing ratio of TS/XG pastes determined from dynamic rheometry exhibited a lower value with increasing sucrose, suggesting solid-like properties contributed from the dissolved sucrose in the systems. Gelatinization temperatures of 25% w/w TS/XG at mixing ratios of 10/0 and 9/1 increased with increasing sucrose content whereas the gelatinization enthalpy of pastes increased in the presence of high sucrose concentration. Sucrose increased the stiffness and hardness of the 25% w/w TS/XG gels (mixing ratios of 10/0, 9.5/0.5 and 9/1) from the compression test. These results suggest that sucrose delays the gelatinization of TS and XG mixtures and strengthens the gels by increasing the elastic component.