Starch-based spherical aggregates: stability of a model flavouring compound, vanillin entrapped therein

Studies on the stability of the vanillin entrapped within the spherical aggregates obtained from amaranth (Amaranthus paniculatus L.), quinoa (Chenopodium quinoa L.), rice (Oryza sativa L.) and colocasia (Colocasia esculenta L.) in the presence of gum Arabic, carboxymethyl cellulose (CMC) and carrageenan at 0.1-1.0% as bonding agents, were obtained by spray drying a 20% (w/w) starch dispersion at 120 degreesC. Vanillin was used at 5% based on starch (bos). The loss of vanillin over a 6-week storage period followed a first order kinetics. The stability was evaluated in terms of t(1/2) (weeks) from a semi-log plot of percentage retention of vanillin vs. storage time in weeks. The t(1/2) for the total vanillin and entrapped vanillin within the spherical aggregates prepared from different starches decreased in the order, amaranth > colocasia > chenopodium > rice. The t(1/2) decreased with an increase in the amylose content of the starches, although it was not linear. With respect to the bonding agent the stability decreased in the order, gum Arabic > CMC > carrageenan. While CMC and carrageenan gave an increasing value of t(1/2) with an increase in concentration from 0.5 to 1.0%, gum Arabic surprisingly gave a higher t(1/2) value at 0.5% as compared to 1.0%. (C) 2002 Elsevier Science Ltd. All rights reserved.