Elaeis guineensis oil, commonly known as palm oil, is a versatile and widely used vegetable oil derived from the fruit of the oil palm tree, scientifically known as Elaeis guineensis. This oil is known for its unique properties and is used extensively in various industries, including food, cosmetics, personal care products, and biodiesel production. In this post we look at the particular properties of palm oil and then at the alternatives because of the political and environmental landscape in its removal from food and pharmaceutical products.
The palm oil industry is now worth $70 billion and its growth is predicted to be $100bn by 2030. The Compound annual growth rate (CAGR) is thus 4.9% between 2023 and 2030 according to Vantage Market Research. That level of growth is highly attractive to anyone in the provision of oils but also to those looking to replace it. It also means increasing levels of deforestation as a result of that profitable attractiveness.
Introduction
The oil palm tree is native to West Africa but is now cultivated in many tropical regions around the world, such as Southeast Asia, Central and South America, and Africa. Crude palm oil (CPO) is extracted from the fleshy mesocarp which is the distinctive red pulp of the fruit. It contains a high amount of oil. The oil palm tree is highly productive, with a high oil yield per unit of land compared to other oil crops, making it an efficient source of vegetable oil.
Manufacturing Processes
Crude palm oil (CPO) undergoes extensive processing before it becomes suitable for sale to the consumer. This manufacturing process has been reviewed elsewhere. One of the critical processes is adsorption bleaching to produce refined, bleached and deodorized palm oil (RBD palm oil).
Fractionation is critical. It separates liquid olein or superolein (palm olein) which is used in cooking oils from solid olein which is used in margarines and shortening (Che Man et al., 1999). There are different types of fractions available and they can be further subdivided. PMF is a hard palm midfraction which can be used as a cocoa butter equivalent (CBE).
A hard PMF is available through multistep fractionation of palm oil by using dry fractionation (DF) coupled to solvent fractionation (SF) using hexane or acetone.
Acetone is a polar solvent which crystallizes symmetrical 1,3-disaturated triacylglycerols rather than nonsymmetrical 1,2- or 2,3-disaturated triacylglycerols. This is the ideal solvent for producing a solid midfraction. Triacylyglyercols are highly soluble in hexane. Temperatures at least 15 degrees lower than those required for acetone must be used for equivalent crystal yields (Hashimoto et al., 2001).
Composition
Palm oil (red palm oil)is mostly composed of three types of triglycerides:-
- trisaturated (mainly PPP that is tripalmitin),
- disaturated (mainly POP that is 2-oleodipalmitin),
- monosaturated (mainly POO that is 1-palmitoyl-2-3-dioleoylglycerol).
The composition is a balanced ratio of mainly saturated and unsaturated fatty acids with the predominant types being palmitic acid (saturated) and oleic acid (monounsaturated). The actual figures are 50% saturated fatty acids, 40% monounsaturated fatty acids and 10% polyunsaturated fatty acids. Palm oil also contains carotenoids, phosphatides, sterols, tocopherols and trace metals. The carotenoids (500 – 700 mg/L) give this oil its red colour (Edem, 2009). Unfortunately most of the beta-carotene is destroyed during processing on further refining .
The melting point has been extensively investigated using differential scanning calorimetry. There are two characteristic endotherms in the temperature range of −23 and 43 °C (Ng and Oh, 1994; Siew and Ng, 1999).
In keeping with the general behaviour of fat mixtures, the high melting point is due to mainly fully saturated triglycerides (trisaturated) and the lower melting point is due to the presence of monounsaturated fatty acids.
Because of its composition based on saturated and unsaturated fatty acids, this oil then is known for its semi-solid consistency at room temperature due to its unique composition. More accurately, the melting point is between 35C and 42C depending on the ratios of these fatty acids.
The balanced composition composition gives palm oil its stability and resistance to oxidation, making it suitable for a wide range of applications.
The degree of fat crystallization is an important characteristic of all fats in terms of their function and performance. The texture, hardness, and spreadability of palm oil depends on the amount, size, and three-dimensional organization of the crystal network.
Palm oil has three polymorphs.
We mentioned earlier how fractionation produces a purely liquid fraction such as palm olein. The other product is a the solid component called stearin.
Palm olein contains more unsaturated fats which keeps it liquid at room temperature. Palm olein is thus rich in oleic
acid (42.7% – 43.9%), β-carotene and vitamin E (tocopherols and tocotrienols) It also has a melting temperature of between 20 and 25ºC. Stearin contains mostly saturated fats. Palm olein is less stable than palm oil so has a shorter shelf-life. That is also down to the greater susceptibility of the unsaturated fatty acids to oxidation.
The fractions have a greater complexity in their crystal structure. The highest-melting point fraction, consisting mainly of trisaturated triacylglycerols, shows the classical α, β’, β polymorphism. The middle-melting point fraction which is rich in POP, has sub α, α and β’1 forms, at low temperatures.
At 18 ºC, the b’1 is transformed into a β’ form that is
transformed into the most stable β form when the temperature reaches 30ºC (Hashimoto et al., 2001; Okawachi & Sagi, 1985).
Applications
In the food industry, palm oil is valued for its functional properties and versatility. It is used in various food products, including cooking oils, margarine, shortening, confectionery, coatings, snacks, and as a base in all sorts of processed foods. Palm oil has a neutral flavor profile, which allows it to be used in a wide array of recipes without overpowering the taste of other ingredients. Its semi-solid consistency at room temperature also makes it a suitable choice for products that require a solid fat, such as spreads and baked goods. The reason it is so useful as an oil is because it remains a solid at room temperature but then becomes liquid at body temperature. It also has considerable importance in cosmetics and soaps as well as biofuel.
Due to it liquid nature, palm olein is used as a cooking oil and especially for frying. You can also find it in salad dressings too.
Nutritional Properties
In addition to its functional properties, palm oil has gained attention for its nutritional composition. It is a rich source of vitamin E tocotrienols, which are potent antioxidants that help protect cells from damage caused by free radicals. Palm oil also contains carotenoids, such as beta-carotene and lycopene, which give the oil its reddish-orange color. These carotenoids have antioxidant properties and are converted into vitamin A in the body, contributing to overall health and well-being. Some nutritionists consider it to be dangerous but there is no evidence to indicate it is any more dangerous than other fats and oils.
Environmental Issues
However, it is important to note that palm oil has also been a subject of controversy due to environmental and social concerns associated with its production. The expansion of oil palm plantations has been linked to extensive deforestation, habitat destruction, loss of biodiversity, and greenhouse gas emissions. The main areas of deforestation is in the replacement of jungle through Far Eastern Asia. The United Nations believed that palm oil harvesting accounted for losses of 7% of the jungle between years 2000 and 2018. Additionally, some palm oil plantations have been associated with issues such as land rights disputes, labour rights violations, and unsustainable farming practices.
To address these concerns, there have been efforts to promote sustainable palm oil production through certification schemes such as the Roundtable on Sustainable Palm Oil (RSPO). The RSPO sets criteria for environmentally and socially responsible palm oil production, including the protection of forests, wildlife, and local communities. The aim is to encourage the adoption of sustainable practices, reduce the negative impacts of palm oil production, and promote transparency in the supply chain.
What Are The Alternatives To Palm Oil?
In recent years, there has also been growing interest in alternative vegetable oils as substitutes for palm oil. These include oils derived from crops such as soybean, sunflower, canola, and coconut. However, it is important to consider the overall sustainability and environmental impact of these alternatives, as well as their functional properties and availability.
1. Sunflower Oil
Sunflower oil, particularly high-oleic sunflower oil, is gaining popularity as a palm oil substitute. It is rich in monounsaturated fats, which are healthier than the saturated fats found in palm oil. Sunflower oil also has good stability and a neutral flavor, making it suitable for various food applications, including coatings. It is not a like for like substitute but has properties that mean a reduction in some properties.
PepsiCo India announced in 2024 that they were replacing the use of palm oil in some of their products with a combination fat of sunflower oil with palmolein. This has been trialled as an alternative for frying crisps and snack products.
2. Coconut Oil
Coconut oil is another alternative, especially in coatings where a solid fat is needed at room temperature. It has a similar melting profile to palm oil, making it a functional replacement. However, coconut oil is high in saturated fats, which may not be ideal for all health-conscious consumers.
3. Shea Butter
Shea butter is derived from the nuts of the shea tree and has similar properties to palm oil. It is used in chocolate coatings and confectionery. Shea butter is solid at room temperature and melts at body temperature, providing a creamy texture similar to palm oil-based coatings.
4. Olive Oil
Olive oil, particularly in its refined form, can replace palm oil in some coatings. It is rich in monounsaturated fats and has antioxidant properties. Olive oil works well in savory applications but may impart a distinct flavor that isn’t suitable for all products.
5. Rapeseed Oil (Canola Oil)
Rapeseed oil is low in saturated fats and high in monounsaturated fats. It has a neutral flavor and good stability, making it suitable for use in food coatings. It is particularly used in frying and baking applications where a stable oil is required.
6. Avocado Oil
Avocado oil is known for its health benefits and high smoke point. It is rich in monounsaturated fats and antioxidants. Avocado oil can be used in various food coatings, particularly for high-temperature applications.
7. Algal Oil
Algal oil, derived from algae, is an emerging sustainable alternative. It is rich in omega-3 fatty acids and has a neutral flavor. Algal oil can be used in a variety of food products, including coatings, due to its stability and nutritional benefits.
8. Blends of Vegetable Oils
Blending different vegetable oils can mimic the properties of palm oil. For example, a mixture of sunflower, canola, and coconut oils can provide the desired consistency, stability, and melting profile needed for food coatings without relying on a single source.
9. Rice Bran Oil
Rice bran oil is known for its mild flavor, high smoke point, and health benefits, including high levels of antioxidants. It is a suitable alternative for coatings, particularly in applications that require high-temperature stability.
Specific Fat Combinations & Precision Fermentation
Precision fermentation is a process of producing ingredients such as palm oil using microorganisms rather than plants. Businesses such as C16 Biosciences in the USA have started producing palm oil alternatives. By growing yeast as would be done in brewing they hope to produce oil rather than alcohol. Typical yeasts include Yarrowia lipolytica, other oleaginous yeasts which include Lipomyces starkeyi, Yarrowia lipolytica, Cryptococcus curvatus, Cryptococcus albidus, Rhodotorula glutinis, Rhodosporidium toruloides and Trichosporon pullulans which entrap the oil in their cells. At the end of fermentation, the cells are harvested and the oil released.
Clean Food Group is a business coming out of the University of Bath in the UK which is also developing palm oil alternatives. A similar venture, Sun Bear Biofuture has also developed their fermentation process. Their feedstock is food waste. They have received grants from a number of UK based businesses which started with a Fast Start award from Innovate UK. This allows the team to express various key enzymes involved in the metabolism of starch.
Benefits and Challenges
Benefits
- Sustainability: Many alternatives have a lower environmental impact compared to palm oil.
- Health: Alternatives often have healthier fat profiles, being lower in saturated fats and higher in unsaturated fats.
Challenges
- Cost: Some alternatives may be more expensive than palm oil.
- Availability: Certain oils, like shea butter and algal oil, might not be as readily available in large quantities.
- Flavor and Functional Properties: Matching the exact texture, stability, and flavor-neutral properties of palm oil can be challenging.
In conclusion, Elaeis guineensis oil, or palm oil, is a widely used and versatile vegetable oil with unique properties. It is used in various industries, including food, cosmetics, personal care products, and biodiesel production. Palm oil’s semi-solid consistency, stability, and neutral flavor make it suitable for a wide range of applications. However, the environmental and social concerns associated with its production have led to efforts to promote sustainable practices.
References
Che Man, Y. B., Haryati, T., Ghazali, H. M., & Asbi, B. A. (1999). Composition and thermal profile of crude palm oil and its products. Journal of the American Oil Chemists’ Society, 76(2), pp. 237-242 (article)
, . (1994). A kinetic study on isothermal crystallisation of palm oil by solid fat content measurements. J Am Oil Chem Soc. 71(10): pp. 1135–9 (Article)
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