Encapsulated orange oil

The shelf-life of virtually all the encapsulated orange oils was quite good. Assuming a Q q of 2.4 (1 ), one would predict a shelf-life of about 7 months at 70°F for the worst product (amylomaize) and at least 14 months for the better products (corn, wheat, rice, waxy corn, and cassava). Considering that there was no antioxidant in these encapsulated products, the shelf-lives are very good. This work supports the observations of Anandaraman and Reineccius (1 ) that high DE maltodextrin or glucose syrup solids provide excellent barrier properties and produce encapsulated citrus oils with excellent shelf-life. 

Fig. 4. Shelf-life of encapsulated orange oil samples, as measured by limonene oxide formation at 37°C.

This study supports the hypothesis that high DE maltodextrins and syrup solids permit the formation of encapsulated products with excellent stability to oxidation. Different enzyme-hydrolyzed starches yielded encapsulated orange oils which varied in stability amylomaize and potato maltodextrins exhibited the poorest stabilities while normal corn, waxy corn, cassava, rice, and wheat glucose syrup solids yielded the best and approximately equivalent shelf-lives. Based on oil retention during drying, amylomaize, wheat, rice, and cassava yielded satisfactory products. 

Table III. The Influence of Emulsion Size on the Shelf-life of Encapsulated Orange Oil...

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. 

The encapsulated orange oil (0.1 g) was rehydrated in 7.5 ml distilled water via the use of a vortex mixer for 30 sec. Acetone (50 pi) containing 100 jug ethyl heptanoate (internal standard) was added and mixed for another 30 sec. This solution was forced through a preconditioned Sep-pak CIS reverse phase cartridge. 

Table I. Mean particle diameter and calculated surface area of encapsulated orange oils...

Figure 1. Particle size distribution of three ENCAPSULATED ORANGE OILS SPRAY DRIED AT DIFFERENT VOLTAGES, a 200 v b 150 v C 75 V.

Analysis of Encapsulated Orange Oil. The influence of particle size on the chemical properties was first examined. The chemical data of three powders are presented in Table II. The moisture content of all powders was quite comparable. 

Table II. Moisture,total oil and surface oil contents of encapsulated orange oil...

The surface oil content of the three encapsulated orange oils ranged from 102 (powder A) to 909 (powder C) mg/100 g powder, which corresponded to 0.67(powder A) and 7.10 (powder C) oil. Powders B and C had about 2 1/2 and 9 times surface oil as compared to powder A. This was not expected since powders with larger diameters had less calculated surface area as shown in Table I. It is therefore speculated that other powder characteristics, e.g. surface morphology, may play an important role on the oil retention properties and should be further studied. 

Figure 2. Scanning Electron Micrographs (120x magnification) of three encapsulated orange oils SPRAY DRIED AT DIFFERENT VOLTAGES A 200 V B 150 V C 75 V.

Powder with large particles was shown to exhibit better protection against oxidation for encapsulated orange oils. However, the effect of particle size may have been slightly offset by the degree of surface imperfection of powders. Except for the morphological imperfections, the protective effect of powders B and C should have been greater than observed. 

Determination of Moisture. A modified AOAC method for ground spices was used for moisture determination of encapsulated orange oil (17). Twenty and 40 gram samples were refluxed in 150 ml anhydrous toluene for 3i hours. All samples were analyzed in duplicate. 

Encapsulated orange oil samples (150 mg) were weighed into 10 ml vials and dissolved in 850 mg distilled water. Four ml of acetone containing 0.25 mg/ml 2-octanone as an internal standard were added dropwise to the dissolved samples. The samples were continuously agitated throughout the addition of the internal standard solution using a vortex mixer. 

Shelf Life. Encapsulated orange oil samples were subjected to accelerated shelf life testing at 37 ad 50 C. Control samples were stored at 25 C. The samples were evaluated until degradation was sufficient to produce a level of 2 mg... 

Figure 1. Emulsion stability of encapsulated orange oil samples.

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