Emulsions Vegetable creaming

This method is relatively easy to use for anhydrous systems, but not for emulsions, foods, or biological media where the presence of water is detrimental. The method has been applied for determining antioxidant activity of both individual natural polyphenols and vegetable extracts. Methods based on this one have been used to evaluate the peroxide value in walnuts (Wilson-Kakashita and others 1995), mango seeds (Joseph 1995), almonds (Uthman and others 1998), and coconut cream powder (Yusof and others 2007). 

Highly concentrated emulsions are also evident in everyday applications. A classic example is mayonnaise, in which a large volume of vegetable oil is emulsified in a small amount of vinegar, using lecithin from egg-yolk as the emulsifier. In addition, HIPEs are most probably found in many cosmetic products, especially gels and creams. However, little information is available on products of commercial importance, so one can only speculate on their exact nature and composition. 

Diehl, K.C., Hamann, D.D., and Whitfield, J.K. 1979. Textural failure in selected raw fruits and vegetables. J. Texture Studies 10 371-400. Fligner, K.L., Fligner, M.A., and Mangino, M.E. 1991. Accelerated tests for predicting long-term creaming stability of infant formula emulsion systems. Food Hydrocolloids 5 269-280. 

Instant whipped cream is based on the same foam-stabilizing principles but is packaged as a liquid (emulsion) and a gas under very high pressure in an aerosol can (see the footnote to Section 15.5). When the can s valve is released, the tremendous gas expansion through a fine orifice drives the formation of the foam topping. In non-dairy instant whipped topping products the cream is replaced by vegetable oil, water, and a number of emulsifiers, stabilizers, and preservative. 

Coffee Creamer. Emulsions of vegetable oil in an aqueous phase, including caseinates, are sold (as pasteurized liquid or as a spray-dried powder) as substitutes for cream for addition to coffee. Eor the liquid form, an emulsifier system of some combination of polysorbate 60, polysorbate 65, and sorbitan monostearate is used at a concentration of up to 0.4%. The spray-dried whitener uses the same emulsifier system, at a level of 1-3% of the dried powder. In both cases, sodium caseinate is probably the major stabilizer of the o/w emulsion. 

The fact that most vegetable oils and fats are nontoxic allows them to be used as reliable excipients or carriers in many pharmaceutical formulations. Vegetable oils and fats have been approved as excipients to facilitate delivery of bioactive compounds, to act as fillers, binders, lubricants, solubilizers, emulsifiers, and emollients in a variety of delivery forms including tablets, capsules, suppositories, emulsions (enteral/parenteral), ointments, creams, and lotions. Other nondirect applications include artificial blood, gene delivery, diagnostic imaging, and medical devices (27). 

Lanolin may be used as a hydrophobic vehicle and in the preparation of water-in-oil creams and ointments. When mixed with suitable vegetable oils or with soft paraffin, it produces emollient creams that penetrate the skin and hence facilitate the absorption of drugs. Lanolin mixes with about twice its own weight of water, without separation, to produce stable emulsions that do not readily become rancid on storage. 

Ice-cream is an O/W emulsion that is aerated to form a foam. The disperse phase consists of butterfat (cream) or vegetable fat, partially crystallised fat. The volume fraction of air in the foam is approximately 50%. The continuous phase consists of water and ice crystals, milk protein and carbohydrates, e.g. sucrose or corn syrup. Approximately 85% of the water content is frozen at —20 °C. The foam structure is stabilized by agglomerated fat globules that form the surface of air cells in the foam. Added surfactants act as destabilizers , controlling the agglomeration of the fat globules. The continuous phase is semi-solid and its structure is complex. 

Palm oil represents about 23% of the world output of vegetable oils and is employed as a food fat in its bulk state, for example in shortening or in emulsions such as margarine and cream [75,76]. The effects of the addition of the SOEs (S-170, P-170, and 0-170) on palm oil in the O/W emulsion were studied by ultrasonic measurements [12], It was shown that S-170 and P-170 reduced the degree of supercooling and hence accelerated the nucleation, yet the effect of 0-170 was negligible. Table 3 shows the Tc of palm oil in bulk and in O/W emulsion, in which the was defined in the same manner as for n-hexadecane. In the bulk without impurities, Tc was 34°C. With the addition of 1 wt% P-170... 

Palm midfraction (PMF), a fraction of palm oil whose melting points are between those of palm stearin and palm olein [77], has been employed for vegetable-fat-based creams as well in the production of cocoa butter equivalent fats (CBEs) used in chocolate [78]. The effects of additions of SOEs and PGEs on the crystallization of PMF in O/W emulsions were studied recently [79]. Figure 13a shows the isothermal crystallization behavior of PMF in oil-in-water emulsion at 10°C without (pure) and with the addition of 1 wt% S-170. It is obvious that the V values of the pure emulsion are always smaller than in emulsions with S-170... 

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