Encapsulation

Microencapsulation of food and pharmaceutical related ingredients by spray drying and the storage stability

The incorporation of hydrophobic flavors into powders by encapsulation is great importance in the food and flavors industries. Microencapsulation of flavors is a technology of enclosing flavor compounds in a carrier matrix to provide dry and free-flowing powders, which are easy to handle. Furthermore, it also provides protection against the degradative reaction and prevents the loss of flavors during food processing and storage. Among various microencapsulation methods, spray drying is the most common technique to produce flavor powders, since it has many merits such as low process cost, wide choice of carrier solids, good retention of flavors, and good stability of the finished flavors. In this research, the main emphasis of the microencapsulation of flavors has concentrated on preventing the flavor losses during spray drying and extending the shelf life of the products. The focus is on the effect of emulsion droplet size, powder size as well as the type of the model flavors. More specifically the aim is to understand the mechanism loss and oxidation of encapsulated flavor from the droplet which directly relate to the shelf life of product. The work is focused on the effect of water activity as well as the change of the capsule structure on the stability of encapsulated flavor. Furthermore, in order to understand the morphology of spray dried powder and encapsulated flavor powder, CLSM was using to view the cross sectional of the spray dried powder and the arrangement of encapsulated flavor in powder without the destruction of the powders.

Encapsulation of flavors by molecular inclusion in cyclodextrins

Cyclodextrin (CD) is a family of cyclic oligosaceharides with truncated molecular structure. The relatively hydrophobic cavity of CD provides a less polar microenvironment in CD solution for the appropriately-sized hydrophobic molecules to reside in. T heir applications are mainly intended for the entrapment of smaller molecules, stabilization of reactive intermediates and drug delivery device as potential molecular transport. In food related applications, flavor compounds are being encapsulated into CDs for better retention and protection from various possible means of deterioration, as well as for controlled delivery. However, the inclusion and release characteristics of the guest molecules have not been fully understood. The aim of this study was to examine the effects of inclusion methods on the properties of inclusion complex powders especially with respect to flavor retention and release of the guest flavor compounds under various temperatures and relative humidities.

Crystal transformation of sugars by ethanol dehydration technique

α,α-Trehalose(α-D-glucopyranosyl α-D-glucopyranoside) is a non-reducing disaccharide found in many organisms as an energy source and protection of living cells from the damage caused by dryness. Since trehalose is also present at low concentration in various food we continually ingest this sugar as part of a daily diet. The main purposes for using trehalose are lowering of sweetness, moisture retention and prevention of starch retrogradation. Trehalose crystal exists in the dihydrate and polymorphic anhydrous crystalline forms, which exhibit complicated polymorphism depending on the given thermodynamic conditions. In this study, an innovative process to produce anhydrous crystal of trehalose with fine porosity using ethanol as the dehydration medium was explored. Using this method, a new type of porous crystal particle with a three-dimensional fine network structure could be obtained. The specific surface area of the anhydrous crystal transformed at 50 °C was 3.3 m2/g, with a median pore diameter of 0.21 μm, and void volume of 0.22 mL/g. The crystal transformation was monitored by measuring the crystal moisture content. The crystal transformation rates could be correlated with the Avrami equation, using the mechanism parameter n = 11.5, suggesting that the change of surface area occurred during crystal transformation from dehydrate to anhydrous trehalose.