Storage Stability of Spray-Dried Blackberry Powder Produced with Maltodextrin or Gum Arabic

Abstract

The aim of this work was to evaluate the stability of anthocyanins and antioxidant activity of blackberry powder, obtained by spray drying, using maltodextrin, gum arabic, or a blend of both carrier agents over a period of 5 months. The inlet air temperature was 145°C and the concentration of carrier agent was 7% (w/w). Samples were stored at 25 or 35°C and at relative humidity of 32.8%. Anthocyanin degradation followed the first-order kinetic model. Temperature negatively influenced the stability of anthocyanins, because these pigments are highly thermosensitive. Antioxidant activity increased for the powders stored at 35°C, probably due to the occurrence of the Maillard reaction, leading to the formation of compounds with antioxidant activity. In general, maltodextrin provided greater stability for spray-dried blackberry powder, because particles produced with this carrier agent showed the longest half-life and the lowest anthocyanin degradation rate at 25°C. The use of maltodextrin or the combination of both carrier agents promoted better maintenance of antioxidant potential of blackberry powder. With regard to morphology, all of the samples exhibited a large number of irregular particles with spherical shapes, but powders produced with gum arabic presented the smallest size and shriveled surfaces, which probably affected their stability, resulting in faster anthocyanin degradation during storage.

Keywords:

• Anthocyanin
• Antioxidant activity
• Carrier agents
• Morphology
• Rubus spp
• Spray drying

ACKNOWLEDGMENT

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

Notes

^a All data are the mean of triplicate measurements ± standard deviation.

^b AOAC = Association of Official Analytical Chemists.

Means with different letters in the same column indicate significant differences at p ≤ 0.05.