Effect of Carrageenan on the Quality of Purple Sweet Potato Frozen Dough and Steamed Buns

Abstract

In order to enhance the stability of purple sweet potato steamed dough and the quality of resulting steamed buns, the influence of carrageenan conditions (0%, 0.5%, 1.0%, 1.5%, 2.0%, mass fraction) on the dough’s moisture distribution, freezable water content, rheological properties, microstructure, and on the specific volumes, water activity, texture, and color quality of steamed buns were studied. Adding carrageenan led to a marked reduction in the freezable water of the purple sweet potato frozen dough, preventing the loss of strongly bound water to free water, improved the modulus of elasticity G' and viscous modulus G'', and finally made the protein network structure of purple sweet potato frozen dough more continuous and denser during the freezing and storage process. In terms of quality of steamed buns, adding carrageenan reduced the hardness while enhanced the elasticity and specific volume, with no significant impact observed on color parameters. In summary, carrageenan could be served as a good quality improver for purple sweet potato frozen doughs, and achieving the best freezing protection effect on the end-product attributes of the purple sweet potato steamed buns when the addition amount was 1.5%.