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Introduction
Palm fruit oil is consumed worldwide in more than 100 countries. In some parts of the world, palm fruit oil is often still consumed in its unrefined state, as an ingredient of traditional dishes, where it contributes its characteristic golden red color and unique flavor. However, to most users, palm oil is more familiar as a refined vegetable oil product purchased at their local store and incorporated into their everyday foods.
You may be surprised to learn that many of the foods you eat are made with palm oil. Baked goods. Instant noodles. Baby formula. Cake mixes. Breakfast bars. Potato chips. Crackers and other snacks. And restaurant foods such as French fries. Palm oil is abundant, and is increasingly recognized as having a role to play in a healthy balanced diet.
Of the oils and fats on the market, palm fruit oil serves well many of might best meet today's consumers criteria. It is healthful, abundantly available, relatively inexpensive, and technically suitable for most food products. Perhaps this is why palm oil has become the largest internationally traded vegetable oil in the world proving its acceptance in the global market.
About 90% of palm oil currently goes into food applications and the remaining 10% goes into non-food applications.
Shortening
The functionality of shortenings to be used in cakes, "buttercream" fillings, biscuits and pastry is dependent on several factors, such as a smooth consistency to facilitate mixing & a fine crystal structure in the solid fat phase. This contributes to smoothness, and is essential in cake making and creaming applications.
A further requirement in bakery shortenings is that they should not melt too quickly during baking. The fat must retain the air bubbles until the cooking process has created structural materials from the other ingredients, mainly gelatinizing starch and egg proteins.
Many manufacturers in countries that are major producers of liquid oils such as rapeseeds, soya or sunflower oils, use them in partially hydrogenated forms as major components of shortenings. In this case, it is difficult to obtain a fine smooth structure because of the tendency of these fats to form rather coarse beta type crystals. It has been established that the incorporation of 15-20% palm oil in formulas based on these hydrogenated oils induces the desirable beta prime type of crystals, and consequently improves performance. This property is equally important in margarines. The shortening formulas in Table 2 are equally suitable for use in various shots pastry and biscuit recipes.
Texturized palm oil on its own, although it has a suitable solid fat content, does not have the right mixing properties for these products. However, one application is of interest. Palm oil can be used as the fat in a convenient "ready mix" short pastry for household use. The mixture is placed in cold store, when it develops a hard brittle texture. It is then mixed with the other ingredients in a powder mixer. All the ingredients are precooled and the mixer is also cooled. Under these conditions, a good distribution of the fat is obtained; but the finished mix retains a powdered form, and can be filled into retail packs using conventional powder packing equipment.
Cooking Oil
Palm Oil has been used as a cooking oil for many centuries.
The most important characteristic of a fat used for frying is its ability to withstand the high temperature used, without excessive chemical change. Frying is usually carried out at a temperature of about 180¢XC. At this temperature, the more unsaturated oils tend to oxidize and either breakdown or polymerize quite rapidly.
Oils containing significant levels of linoelic acid are not recommended for frying, unless they have been hydrogenated to reduce the content of these labile components.
Palm oil, with its moderate linoelic acid content and high level of natural antioxidants, is suitable for direct use in most frying applications, and frying is a major use of palm oil worldwide.
Palm oil used domestically, in restaurants, fast food outlets and in large-scale preparation of fried potato products and other snack foods in large-scale food manufacture. In the East, a comparable use is in the preparation of instant noodles. This practice started in Japan, using palm oil to replace animal fats, and is now also common in South Korea and China.
For the large scale frying of potato chips, palm olein or a blend of palm olein with soya or rapeseed oil is preferred. This is because the surface appearance of the finished product is improved. French fries are often purchased as part fried and deep frozen products.
The manufacturing process involves deep-frying followed by rapid cooking and blast freezing. Quick crystallization of the fat used is important and for this reason, a slightly hydrogenated palm oil of melting point 40-42¢XC is preferred.
Provided good temperature control and cleanliness of the oil by filtration, palm oil products have an exceptionally good life in the frying process and are therefore economical.
Margarine
Margarines were originally developed in 1869 as an alternative to butter, which was in short supply and expensive. The first margarines were made from animal fats, but today most margarine is formulated with vegetable oils. The product range now includes table margarines, bakery margarines, specialized puff pastry margarine, and has recently been extended to various "low calorie" spreads, which essentially contain much higher levels of water and lower levels of fat than those legally required in margarine.
Table margarines fall into two main types, packet margarines which are designed to be spreadable at ambient temperature, and tub margarines which are spreadable on removal from the refrigerator, at a temperature of 5-10¢XC. Typically solid fat content curves for the two types are illustrated in chart 2, which shows the much lower solid fat content required in the tub margarine.
When packet margarines are intended for use in a tropical climate, with ambient temperatures around 30¢XC, higher solids contents than those indicated in Chart 2 are required to avoid melting.
With the availability of hydrogenated oils of various grades, there is a large choice of ingredients for blends with the desired solids content profiles. Individual manufacturers will usually base their choice on local availability and on price, as well as the technical consideration of a fine crystal structure to give the required spreadable character.
Palm oil and palm kernel oil are highly suitable components of margarines of the various types described, and numerous formulas have been published in the technical literature.
The following advantages can be listed for palm oil:
- It provides the required solid fat content with little or no hydrogenation.
- It ensures the stable beta prime crystalline form necessary for a fine structure.
- It is readily available worldwide at very competitive prices.
Palm kernel oil contains short and medium chain length glycerides similar to those present in butterfat, and therefore helps to give the right mouth feel and melting characteristics. This effect is particularly marked when it is used in combination with palm oil, because a lower melting eutectic is formed.
The professional baker often prefers to use margarine in the production of cakes instead of a (100% fat) shortening. Margarines usually have added color and flavor, which contribute to the end product, and are therefore particularly suited to use in butter cream fillings.
Bakery margarines are formulated to a higher solids content than table margarines to ensure good baking properties.
Confections
Chocolate products are regarded the world over as a special "treat." Their attraction lies in the unique flavor of the roasted cocoa bean, and in the characteristic brittle texture, the "snap" and the "crunch" experience in breaking and chewing. This texture is derived from the fat and must be accompanied by a rapid melt-in-the-mouth sensation and no residual greasy feeling.
These properties are inherent in the two-oleo-disaturated glycerides which form more than 75% of cocoa butter. The search for other fats with similar behavior has resulted in two different solutions based on palm oil.
1. Cocoa butter equivalent fats
These fats can be mixed with cocoa butter in any proportions. Their main component is a mid-fraction of palm oil, which is obtained by a careful double fractionation from solvent to remove the more liquid and the high melting components. Such a fraction has a high proportion of the desired two monounsaturated glycerides.
In milk chocolate, where the butterfat has a softening effect, the palm mid-fraction needs to be reinforced by two-mono unsaturated glycerides from one to other tropical nut oil.
2. Cocoa butter extenders or replacers
These fats can only be mixed with cocoa butter to a limited extent without causing softening and loss of appearance during storage. A successful product is based on a double fractionated polein, rich in POO glycerides, which is then partly hydrogenated. As an extender, this fat can be used at 10-15% of the cocoa butter content. Alternatively, is can be used as the sole fat component in a variety of chocolate flavored confections or coatings, using fat-free cocoa powder.
A third type of confectionery fat is based on fractionated or partly hydrogenated palm kernel oil. A variety of products tailor-made for particular applications such as toffee fats and bakery coatings is available.
For use as chocolate flavored coating on ice cream bars or in the USA as "popsicles", neither palm oil nor palm kernel oil or cocoa butter are very suitable. At the low temperature at which such products are eaten, the coatings are very brittle and tend to flake off. It is usual in this application to blend palm or palm kernel oil with a high quality liquid oil, such as ground nut oil, to give the right physical behavior.
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