Starch based spherical aggregates: reconfirmation of the role of amylose on the stability of a model flavouring compound, vanillin

The stability of the total vanillin (TV) and entrapped vanillin (EV) within the spherical aggregates prepared from various starches over a 6-week storage period appeared to be correlated to the amylose content of the starches, in a previously conducted study. To reconfirm this observation, spherical aggregates were prepared from amaranth starch (containing 2.5% amylose), and from blends of amylose and amaranth starch (in ratios of 10:90, 20:80, 30:70 and 40:60 ratios) of vanillin (used at 5% based on starch) using gum Arabic at 1.0% as the bonding agent. The loss of TV and EV from the spherical aggregates followed a first order kinetics, from which the stability was evaluated in terms of t1/2, the time required for TV or EV to decrease to 50% of its original value. The t1/2 for the TV and EV within the spherical aggregates so prepared were evaluated as a function of the added amylose. The t1/2 for TV remained almost unchanged with amylose up to 20%, thereafter decreased substantially at 30%, and very sharply at 40%. With EV, the decrease in t1/2 was less up to 30% amylose in the blend, but decreased very sharply at 40% amylose. These results confirm our earlier observation of the role of amylose on the stability of EV and TV within the spherical aggregates.