Effects of Spray-Drying Conditions on the Physicochemical Properties of Blackberry Powder

Abstract

The purpose of this work was to study the effects of spray-drying conditions on the physicochemical characteristics of blackberry powder using a central composite rotatable design. Inlet air temperature (140–180°C) and maltodextrin concentration (5–25%) were employed as independent variables. Moisture content, hygroscopicity, anthocyanin retention, color, powder morphology, and particle size were analyzed. A higher inlet air temperature significantly increased the hygroscopicity of the powder, decreased its moisture content, and led to the formation of larger particles with smooth surfaces. Powders produced with higher maltodextrin concentrations were less hygroscopic, slightly lighter and less red, and had a lower moisture content. Anthocyanin retention was mainly affected by drying temperature due to the heat sensitivity of the pigment. The optimal processing conditions were an inlet air temperature of 140–150°C and maltodextrin concentration of 5–7%. Overall, these results indicate that good quality powders can be obtained by spray drying, with potential applications for the food industry.

Keywords:

• Anthocyanin
• Atomization
• Hygroscopicity
• Maltodextrin
• Powder morphology
• Rubus spp

ACKNOWLEDGMENT

The authors thank FAPESP (process number 2010/02561-1) for financial support.

Notes

AOAC = Association of Analytical Chemists.

T _in = inlet air temperature; MC = maltodextrin concentration; X = moisture content; H = hygroscopicity; AR = anthocyanin retention; L* = lightness; H* = hue angle; D[4.3] = mean particle diameter; T _out = outlet air temperature.

X = moisture content; H = hygroscopicity; AR = anthocyanin retention; L* = lightness; H* = hue angle; D[4.3] = mean particle diameter; F _c  = calculated F values; F _t  = tabulated F values (p ≤ 0.01); Ns = nonsignificant (p > 0.01).