Encapsulation of Gallic Acid with Acid-Modified Low Dextrose Equivalent Potato Starch Using Spray- and Freeze-Drying Techniques

摘要

The main objective of the present study was to investigate the effect of spray-and freeze-drying techniques on the microencapsulation of a gallic acid compound using the acid-hydrolyzed low dextrose equivalent potato starch as a wall material. During the experiment, it was possible to achieve encapsulation efficiency of 70-84% for the freeze-dried and 65-79% for spray-dried samples, without statistically significant difference (P0.05) in the encapsulation efficiency between the mentioned methods. Spray-dried samples formed spherical capsules with a higher number of micropores. Meanwhile, freeze-dried samples were shapeless, exposed larger pore volume (from 2.4x10(-3) to 9.5x10(-3) cm(3)/g against 1.2x10(-3) 4.9x10(-3) cm(3)/g; analyzed by Barrett-Joyner-Halenda method) and overall higher surface area (0.632-1.225 m(2)/g against 0.472-1.296 m(2)/g; analyzed by Barrett-Joyner-Halenda method). Due to this fact, more gallic acid molecules were exposed to environmental factors and can be counted as losses. In addition, freeze-dried samples demonstrated lower water activity than spray-dried samples (0.075 +/- 0.014 against 0.178 +/- 0.008). Results showed that it is not practical to use freeze-drying for modelling encapsulation for food industry without a special necessity for protection of easily degradable chemical compounds. The present work makes a basis for the future studies of the microencapsulated phenolics application in food production.