Surface oil content

At lower oil usage levels (20% - 307o) gum arabic and starch octenylsuccinates performed equally. High oil levels (greater than 407o) showed marked differences in surface oil content of the powders, with the starch octenylsuccinates out performing gum arabic. Less flavor oil on the surface of the powder will help improve overall shelf-life stability. 

Table IV. Influence of Emulsion Size on the Surface Oil Content of Spray Dried Orange Oil...

Figure 4. Influence of dryer inlet and exit air temperatures on the surface oil content of spray dried orange peel oil.

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. 

This kind of surface imperfections (fissures, shrinkages etc.) damaged the surface integrity of the spheres and may have resulted in the increase in actual surface area as compared to calculated value in Table I and subsequently have increased the surface oil content for large particles. Surface imperfections have been well documented in the literature when slow process of film formation of drying droplets is encountered. 

The emulsifiers and emnlsifying techniques to produce nanoparticle encapsulated powders (Jafari et al., 2007a). In the case of fish oil encapsulated in maltodextrin combined with modified starch or whey protein concentrate, spray-dried powders were obtained from nanoemulsions (210-280 nm) prepared by microfluidization, with a good efficiency (Jafari, 2009). And the satnration of the carrier solution of wall materials influenced the flavor retention and surface oil content (Penbundiktul et al., 2012). 

Another type of gravity separator used for small amounts of oily water, the oil interceptor, is widely used both offshore and onshore. These devices work by encouraging oil particles to coalesce on the surface of plates. Once bigger oil droplets are formed they tend to float to the surface of the water faster and can be skimmed off. A corrugated plate interceptor (CPI) is shown below and demonstrates the principle involved. However there are many varieties available. Plate interceptors can typically reduce oil content to 50-150 ppm. 

Oil content does not materially decrease flowability. For example, the addition of oils and fats to animal-feed ingredients improves the quahty of pellets made from these materials, making the pellet surfaces harder and enabling the pellets to resist attrition. 

Analysis of Spray Dried Samples. Moisture content was determined in duplicate via toluene distillation and total volatile oil by Clevenger (l ). Surface oil was measured by Soxhlet extraction (2). Shelf-life was determined by gas chromatography (6) the end of shelf-life was the time taken (at 37 C storage) to reach a limonene epoxide concentration of 2 mg/g oil. 

The resultant powders were analyzed for moisture content (toluene distillation), surface oil (Soxhlet... 

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