Effects of Guar Gum on Quality of Soft Tofu Stew Sauce

The aim of this study was to investigate the effects of guar gum on the rheological behaviors, sensory attributes, and consumer acceptability of soft tofu stew sauce. Five different soft tofu stew sauces were commercially manufactured with various levels of guar gum (0.0, 0.1, 0.2, 0.4, and 0.5%). Twelve sensory attributes of the stew sauces were identified by nine trained descriptive panelists, whereas hedonic levels of the stew sauces were assessed by a group of 51 consumers. Steady flow of the stew sauces were measured by a rheometer. Significant differences were observed in terms of sensory saltiness and viscosity among the products. For the consumer test, 0.1% guar gum-added product was most liked by consumers. Partial least square regression showed sensory shellfish, green onion, and shrimp flavors to be key factors affecting overall acceptability for the stew sauces. For rheological behaviors, 0.0, 0.1, and 0.2% guar gum-added products showed newtonian behaviors (R 2 =0.99 by power law model), whereas 0.4 and 0.5% products followed pseudoplastic behaviors (R 2 =0.99 by power law model). Based on the established equivalence table using rheological and consumer data, smaller than 0.0114 (Pa·s) of the apparent viscosity should be necessary to guarantee 'slightly like' category in a consumer hedonic test. It seems that addition of guar gum not only influenced rheological properties but overall acceptability for the stew sauces.