Abstract

The aim of study was to evaluate the effect of the temperature and concentration of yam starch and pectin on the rheological properties of yogurt. A stationary test was performed using an MCR 302 (Anton Paar) rheometer with concentric cylinder geometry, varying the strain gradient in an ascending (0-100/sec) and a descending (0-100/sec), at different temperatures (10, 20 and 30°C, respectively). Yogurts were made using two varieties of yam starch (“Espino” and “Criollo”) and different concentrations of yam starches (0.1, 0.3 and 0.5% w/w, respectively) and pectin at 0.3% w/w was used as a commercial reference. The experimental data were fitted to the power law models, Herschel-Bulkley and Casson. The model that best represented the rheological data was the power law $(R^2≥0.977, MSE≤0.674)$. Yogurts with an addition of yam starch presented thixotropy and pseudoplastic behavior $(0 < n < 1 )$; However, when pectin was used at 30°C the behavior was dilating (n = 1.23). Yogurts with “Criollo” yam starch have higher consistency, while yogurt with an addition of “Espino” yam starch are more pseudoplastic and have less thixotropy.

Keywords:

Consistency coefficient, flow behavior index, flow curves, hydrocolloids, rheological models,

References

Competing interests

The authors have no competing interests.

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The authors have no competing interests.