Retention of β-carotene encapsulated in a trehalose-based matrix as affected by water content and sugar crystallization

Retention of beta-carotene encapsulated in an amorphous trehalose-gelatin matrix and surface color changes were studied during storage of samples at several water activities. The fractional retention could be described by a first order reaction kinetics. The higher retention of P-carotene (about 80% in 6 mo) was obtained in the not crystallized samples, while for crystallized samples exposed to water activity 0.75 the loss was almost complete. Trehalose crystallization could not be delayed by the presence of MgCl2 as occurs in the pure sugar systems. Surface color change was not a sensitive. indication of carotene retention, which was mainly related to excess water over that needed to form the dihydrate crystals.