Rheological and Sensory Evaluations of Sweet Corn Maturity

Abstract

Rheological parameters were evaluated in comparison with other objective tests in order to assess their relative merit as indices of sweet corn maturity and sweet corn quality as determined by sensory evaluation. Three sweet corn varieties, Mellogold, Trail Blazer and Jubilee, were harvested to provide a range from slightly immature to slightly over-mature. Rheological parameters were determined on slurries of preblanched corn by applying power-law flow models to data obtained using the Haake Rotovisko and Brookfield viscometers. The Rotovisko flow behavior index was almost equal to moisture content, refractive index, specific gravity and yield in its correlation with days silking to harvest, used as the standard time index, and was superior to succulometer volume and tests using the Ottawa Texture Measuring System. The corn slurries decreased in pseudoplasticity as maturity advanced. Some of the other rheological parameters, Rotovisko apparent viscosity, and Brookfield consistency coefficient and flow behavior index, were also well correlated with corn maturity.The corn was evaluated by sensory panels for succulence, tenderness/maturity, flavor and overall acceptability. Tenderness/ maturity was generally more closely related to overall acceptability than were succulence and flavor. Correlations between the objective maturity parameters and sensory evaluations revealed that the Rotovisko flow behavior index was equal to the good maturity indices in its correlation with panel parameters and was slightly superior in its relation with overall acceptability.