Oxidation encapsulated flavors

As can be seen from the data in TABLE 5 the low viscosity starch octenyl-succinate closely matches the oxidation resistance of gum arabic. This product would offer improved shelf-life over a standard starch dextrin and similar stability to a gum arabic encapsulated flavor. 

Encapsulated Flavors. Modified procedures during the past decade have permitted the preparation of encapsulated flavors with flavor levels over twice that of prior available products. Spray drying has been the principal key to this success. First, an oil flavnr is emulsified into an aqueous solution or is dispersed in an edible carrier material, after which the emulsion is pumped through an atomizer into a high-temperature chamber. The water evaporates rapidly, and particles of carrier material are formed around the flavor. However, some of the flavor component reaches the surface of the product. This requires the addition uf antioxidants to suppress oxidative changes in the flavor ingredient. 

Release and Oxidation of Encapsulated Flavors during Storage.12... 

RELEASE AND OXIDATION OF ENCAPSULATED FLAVORS DURING STORAGE... 

Figure 1.12 is a schematic illustration of a spray-dried particle in a humid air environment in which the particle would adsorb water vapor this is then followed by state changes of carrier matrices from the amorphous state to a rubbery state. The encapsulated flavors can easily move in the matrix of the carrier matrices. At the same time, the oxygen uptake into the wall matrix becomes higher and the oxidation of the encapsulated flavors progresses. The most interesting point is that around the glass transition temperature, both release and oxidation rate constants change nearly in the same trends with T- T, as shown in Figure 1.11. This implies that the flavor diffusion and the oxygen upt e can be treated as a similar behavior.

Liquid food ingredients encapsulated traditionally have been oil-soluble flavors, spices, and vitamins. However, in recent years, the encapsulation of 3-n polyunsaturated fatty acids (PUFAs) for improved cardiovascular health has received much interest recently. Fish oils contain desired PUFAs and are microencapsulated in order to increase resistance of the PUFAs to oxidation. Encapsulation also provides taste-masking. A human feeding study established that the ra-3 PUFAs in a microencapsulated fish oil have the same desired effect on platlet ra-3 fatty acid profile as unencapsulated fish oil (64). Figure 12 is a photomicrograph of commercial capsules loaded with PUFAs. 

In the following sections, encapsulation of flavor by means of spray drying will be discussed. We will focus on flavor retention during spray drying, stability of the encapsulated flavor on the basis of emulsion properties, and on the release and oxidation rates in the spray-dried powder. 

Release and Oxidation of the Encapsulated Flavor During Storage... 

Figure 6.30 is a schematic picture of a spray-dried particle in a humid air environment, in which the particle can absorb water vapor, followed by a state change of the carrier matrix from amorphous into rubbery. The encapsulated flavor can easily move in the rubbery carrier matrix. At the same time, oxygen uptake into the matrix wall becomes stronger, and oxidation of the encapsulated flavor progresses. Most interestingly, around the glass transition temperature both the release... 

Surface oil refers to the flavoring oil that is on the surface of an encapsulated flavoring material. This surface oil is of particular interest since it is exposed to light, oxygen, and package environment and will readily become oxidized and potentially produce an off-flavor in the product. 

Viability of Starch Derivatives as Flavoring Encapsulants. The capillary GC vapor phase flux term (defined by a percent external standard or ZEStD flux) previously described (34) was used to screen starch derivatives (oxidized, dextrinized and/or covalent amino acid linkage) as to their flavor encapsulation potential. The samples were prepared as previously described (34) with the exception of an added reduced pressure deaeration step, thus allowing the use of the headspace diffusivity versus retention standard curves to predict volatile lemon oil retention following spray drying. 

Another important aspect of encapsulation efficiency is the resistance to oxidation that the carrier imparts to the flavor oils. The oxidation resistance properties are critical to shelf-life stability of the encapsulated product. Oxidation properties can be measured organoleptically by a taste panel or by gas chromatograph of the recovered oil. Peaks related to oxidation products of orange terpenes obtained from GC analysis can be monitored as the powders are aged for three days at 80 C. The GC was used to measure beta-pinene, an oxidation product of orange terpenes. The results are reported in square inches. The greater the area for the beta-pinene peak, the poorer the oxidation resistance of carrier towards the orange terpenes. The data is presented in TABLE 5 ... 

The purpose of this study was to investigate the effect of particle size on encapsulated orange oil, a widely used flavor which is highly susceptible to oxidation, using a readily available laboratory scale spray dryer. A close examination of the surface morphology was also attempted. 

Gas Chromatographic Analysis. The contribution of limonene-1, 2-epoxides and carvone to the development of oxidized flavor of encapsulated orange oil has been investigated (5). The concentrations of these two compounds were reported to provide a reliable index of the stability of the encapsulated orange oil. 

Sensory Evaluation. Results on the sensory evaluation of the three encapsulated powders showed that all three powders developed oxidized flavor even at first sampling time (3 days). Since an expert trained panel was used, the recognition threshold of members for oxidized flavor was far below the expected value. In addition, since oven stored samples were evaluated against freezer stored samples in the pair comparison test, panelists could not characterize the degree of difference in oxidized flavor between various powders. It is therefore suggested that lower storage... 

The primary benefit claimed in this patent was the maintainence of fresh flavor in encapsulated citrus oils which otherwise would readily oxidize during storage, yielding objectionable off-flavors. While spray dried flavorings have continued to dominate the dry flavor market, encapsulated products have been gaining market share. Initial studies that led to the work of Swisher (1 ) were done by Schultz et al (2), This work involved the addition of citrus oils to a molten solution of sucrose and dextrose, cooling the solution to form a hard slab similar to rock candy and then grinding the solid to the desired size. 

Little work has been published comparing the shelf life of flavors encapsulated by different processes. The purpose of this investigation was to determine the shelf life of cold pressed orange oil encapsulated by spray drying, extrusion, and molecular inclusion. Limonene-1,2-epoxide concentration was used to monitor oxidation. 

Two remarkable and unique properties of molecular encapsulation are protection against atmospheric oxidation and disproportionations between components of flavors. In addition,intermolecular transformations are almost entirely eliminated due to the surrounding cyclodextrin ring. 

---