Effect of Different Drying Methods on Rheological and Textural Properties of Balangu Seed Gum

Abstract

The purpose of the present study was to investigate the effect of different drying methods on the rheological and textural properties and color changes in Balangu seed gum. Three drying methods, including air drying (40–80°C), freeze drying, and vacuum drying, were used. The apparent viscosity decreased from 0.161 to 0.056 Pa s with increasing temperature from 40 to 80°C (shear rate = 60 s⁻¹) and freeze-dried gum exhibited the highest viscosity among all dried gums (0.203 Pa s). Different time-independent rheological models (power law, Bingham, Herschel-Bulkley, Casson, and Vocadlo) were used to fit the experimental data and the results revealed that the Herschel-Bulkley model was the most suitable to describe the flow behavior of Balangu seed gum over the whole experimental range (r > 0.98). The hardness values of air dried Balangu seed gum gels varied from 33.1 to 40.4 g and were significantly lower compared to the freeze-dried and vacuum-dried gums (46.9 and 46.6, respectively). The consistency of samples decreased from 386.27 to 245.33 g · s when the drying air temperature increased from 40 to 80°C. The results indicated that the freeze-dried gum exhibited the highest hardness and consistency. The color of air-dried gum was darker (lower L* value) compared to the freeze- and vacuum-dried samples.

Keywords:

• Drying
• Gum
• Image analysis
• Polysaccharide
• Rheology
• Texture

Notes

CS = Control sample, AD = air drying at 40–80°C, FD = freeze drying, VO = vacuum oven.

CS = Control sample, AD = air drying at 40–80°C, FD = freeze drying, VO = vacuum oven.

CS = Control sample, AD = air drying at 40–80°C, FD = freeze drying, VO = vacuum oven.

CS = Control sample, AD = air drying at 40–80°C, FD = freeze drying, VO = vacuum oven.

CS = Control sample, AD = air drying at 40–80°C, FD = freeze drying, VO = vacuum oven.

AD = air drying at 40–80°C, FD = freeze drying, VO = vacuum oven.

CS = Control sample, AD = air drying at 40–80°C, FD = freeze drying, VO = vacuum oven, L = brightness (+100)/darkness (+0), a = redness (+120)/greenness (−120) coordinate, b = yellowness (+120)/blueness (−120) coordinate, C = chroma.

Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ldrt.