Rediscovering Fats & Oils
Fats and oils, once shunned, are now prized for function, nutrition, and flavor
The acceleration of successful launches of healthy products is driving a demand for healthier fats and oils. Specialty oils and fats are an important beneficiary of this growing trend.
Fats and oils—the common terms used for dietary lipids—have distinctly opposite connotations in physical state, consistency, stability, source, and even health implications. Historically, “fats” referred to solid saturated fats that, until recently, were considered unhealthy and generally included animal-sourced butter, lard, and tallow. Lumped into this unhealthy solid fat category—mostly erroneously, as science would later prove—were some plant-based solid fats derived from coconut and palm kernel sources.
Oils, though predominantly regarded as the healthier fat form, also garnered their share of disdain. This was especially true of such commodities as corn and soybean oil. Research-based nutrition knowledge and ingredient technology have turned this around and today, dietary lipids, especially specialty oils, are emerging as functional and nutritious, beneficial to health, and flavorful. In fact, some oils, taking a cue from that darling of the Mediterranean Diet, olive oil, have become “destination” ingredients.
The term “specialty oils” refers to non-commodity oils that can have special dietary or functional properties. In addition to being a source of concentrated energy, specialty oils and fats are a source of valuable nutrients including oil-soluble vitamins and precursors of vitamins. They also are important as textural elements and flavor carriers, and strongly influence the palatability and consumer acceptance of finished food products.
Nut oils from almond, macadamia, peanut, pistachio, hazelnut, and walnut; along with oils from sesame, avocado, flax, hemp, and grapeseed, are becoming popular not only for health and cooking, but also in the packaged foods sector across a range of food categories. For these applications, consistency in taste, biochemical profile, and tolerance to heat are of utmost importance.
Specialty oils tend to be rich in desirable antioxidants and specific fatty acids, plus bioactive compounds such as phospholipids, phytosterols, and polyphenols. Sources range from marine animals and algae to tree nuts, cereals, and even berries.
Tree nut oils typically possess high amounts of monounsaturated fatty acids (MUFA), as well as polyunsaturated fatty acids (PUFA), predominantly linoleic and linolenic acids. Along with some cereal oils, they are gaining popularity in nutraceutical and specialty food applications.
The majority of specialty oils are derived from seeds, nuts, and fruits by cold-pressing. This process retains essential omega-3 and omega-6 fatty acids, as well as lipid-soluble vitamins and other nutrients, such as tocopherols, tocotrienols, sterols, squalene, carotenoids, chlorophyll, and other polyphenolic compounds. Conventional oil extraction and refining processes used for commodity oils typically remove these valuable bioactive fatty acids and bioactive lipids.
Most specialty oils contain phospholipids as an intrinsic component. Commercial phospholipids, such as lecithin, however, are generally byproducts from the processing of soybean oil and other vegetable oils. A glycerol backbone of phospholipids is bound to bioactive fatty acids and phosphoric acid. The addition of an alcohol group, usually choline, ethanolamine, serine, or inositol, allows phospholipids to act as surfactants and form bilayers or micelles and liposomes. These formed compounds are vital to the functionality of cell membranes.
While specialty oils are particularly valued for their potent phytonutrients, they also bring characteristic aroma and flavor to formulations. These attributes are typically stripped during the extraction and refining of commodity oils because of the latter’s focus on producing a final product that is mostly neutral triglycerides.
The removal of bioactive compounds and any potentially toxic compounds during the refining step is essential for consistency and shelflife stability. Both are of high importance in large-scale manufacturing, where consistency is a hallmark of quality.
In the case of specialty oils, the processes of extraction and purification focus on preserving the potential beneficial components in the oil, along with those that contribute to the flavor and aroma of the oil.
Mechanical pressing and cold-pressing are less harsh than the processes that commodity oils are subjected to, such as solvent extraction and purification using alkalis.
Sedimentation and filtration help remove solids while retaining the color, flavor, and aroma of specialty oils from walnut, virgin olive, hazelnut, pistachio, and sesame. Specialty oils are also subjected to live steam under high vacuum and high temperature for deodorization like the commodity oils and are instead blanketed with nitrogen for further protection against oxidation.
When oils are marketed for functional or nutraceutical applications, the manufacturers require “clean” ingredients and processing materials that will allow them to label the final product as natural or organic.
Organic, cold-pressed, and extra- virgin oils typically have a high smoke point and a neutral taste, as well as versatility in application. For those reasons, oils like sunflower oil are gaining ground in the specialty sector. Functionality, clean label attributes, and versatility—along with heart-healthy monounsaturated and polyunsaturated fats—are making sunflower oil popular again.
Bioactive lipids, such as omega-3 fatty acid concentrates, phytosterols, tocopherols, and tocotrienols, require extraction processes that do not degrade or harm the final product. Also, conventional extraction solvents, such as hexane, are not advisable for extraction of heat-sensitive bioactive lipids. This is because complete removal of this toxic solvent from the final product requires harsher processing conditions that can compromise the oil’s bioactivity.
Processing of specialty oils has become more sophisticated in recent years, with the adoption of short-path distillation, preparatory chromatography, and supercritical extraction technologies. These technologies retain and concentrate the oils’ bioactive components like omega-3 fatty acids, carotenoids, tocopherols, and squalene. Short-path distillation of marine oils helps remove volatile contaminants, such as PCBs (polychlorinated biphenyl), dioxins, and furans—toxic and potentially carcinogenic compounds.
Oils and fats are based on two simple building blocks: glycerol and fatty acids. While there is only one type of glycerol, fatty acids can vary widely in their structure.
Fat is essential to maintaining good health and it provides more energy per unit weight (9 kcal/g) than any other nutrient. Triglycerides provide lubricity to foods.
Lubricity, defined as preventing cohesion between surfaces and reducing friction, manifests itself in a number of ways. These include ease of handling, separation of gluten in doughs, and tenderization of texture (shortening effect), as well as mouthfeel characteristics such as tenderness of foods, richness, and improved eating qualities.
Mouthfeel can apply to liquid oils forming an oily film and to how well the fat melts at body temperature to yield a pleasant cooling sensation, rather than a waxy or pasty feeling. The triglyceride structure of fats and oils is important because functionality in food products depends on four types of triglycerides, often grouped by melting points.
The first group, “Group 1 triglycerides,” consists of tri-unsaturated and di-unsaturated components. They possess melting points ranging from about -13°C (8.6°F) to about 1°C (33.8°F). Soybean oil, for example, contains 55% linoleic acid, of which about 20% is trilinolein. More than half of the triglycerides in soybean oil contain from four to six linoleic acid moieties (functional groups within a molecule), which accounts for the oil’s low melting point and tendency to remain a clear liquid at low temperatures. This means formulations such as salad dressings can be stored at refrigerator temperature.
For processors, oils with high amounts of these triglycerides allow for easy pumping and handling in refineries and food service facilities. Moreover, oils high in linoleic acid are a rich source of essential fatty acids needed for human nutrition.
Group 2 triglycerides melt at temperatures between 5.6°C (42°F) and 22.8°C (73°F). They include triolein (OOO) and monosaturated (palmitic/stearic) and di-unsaturated acids (oleic, linoleic) SOL, OOP, and SOO, where P = palmitic, S = stearic, O = oleic, L = linoleic. These provide lubricity at room temperature, and will remain liquid only if stored at ambient temperature.
Group 3 triglycerides melt at near body temperature 27.2-41.7°C (81–107°F). As such, they contribute greatly to mouthfeel. They consist primarily of monosaturated and disaturated forms, and aid in the aeration of doughs and other baked goods, providing a moisture barrier.
Group 4 triglycerides consist of elaidic-containing glycerides esterified to palmitic, stearic, and oleic acids. They are formed by partial and complete hydrogenation of common vegetable oils (soybean, cottonseed, palm oils) and do not exist to any great extent in vegetable oils. These triglycerides melt at temperatures ranging from 56.1-65.6°C (133-150°F) and provide structure at ambient and cooking temperatures. They are popular in the formulation of baking and frying shortenings.
Although highly functional and versatile, Group 4 triglycerides can contribute excessive amounts of both trans-fats and saturated fatty acids. These have been deemed harmful to health, leading to labeling and other regulations and an industry-wide movement to replace them.
Consumers and product developers alike have been facing some confusion about the healthiness of saturated fats. While public opinion continues to vacillate over whether saturated fats are unhealthy or healthy, the national dietary guidelines continue to advocate for unsaturated fats over saturated fats.
Meanwhile, products made with butter and coconut oil are on the rise, due to the perception that they are natural and, therefore, “better for you.” In general, consumer worries about fats and oils are shifting away from their nutritional aspects and toward the use of adulterants and chemical methods of processing.
“Concern about chemical contaminants in processed oils is turning people away from labels with chemical-sounding additives, such as those used to extend shelflife and fry life,” says Mathieu Kohlmeyer, CEO of specialty oil producer La Tourangelle Inc. “Large-scale chip and snack brands are turning to expeller-pressed specialty oils, such as sunflower oil, a high-oleic, high-temperature oil, for functionality and marketing appeal.”
The “clean label” trend favors ingredient lists without additives such as tert-butylhydroquinone (TBHQ), used to extend shelflife and deter rancidity. Such concerns also have prompted calls to boycott palm oil when it contains 3MCPD (3-monochloropropanediol), a genotoxic, carcinogenic chemical and a process contaminant because it is not added intentionally to food, but is produced during the refining of palm oil.
Product developers are responding to these issues with raw, cold-pressed, organic, and artisanal oils and applying those options to not just small-scale production but also to larger batch processing by large food companies.
Unrefined avocado, olive, and grapeseed oils are increasingly used in production of potato chips, for example.
The terms “raw” and “cold-pressed” convey wholesomeness and safety in the sense that the oils are produced carefully and that heat has not destroyed its valuable nutrients. “Specialty oil gives permission to eat products like chips without feeling too guilty,” suggests Kohlmeyer.
Incorporating such specialty oils in prepared foods can be a tall order. It requires marketing, R&D, and plant operations to pay special attention to supply chain availability and scalability. Not all specialty oils can be scaled up to large quantities without losing some of the quality and unique attributes of artisanal facilities.
There is also a significant price differential that does not convince all purchasing departments to switch to specialty oils from commodity oils. But supply and demand factors and improved oil production and handling technology are helping.
“Suppliers can assist with these issues,” assures Kohlmeyer. “Processes can provide a certain amount of proprietary power in terms of aroma and flavor—attributes that are responsible for consumer perception of quality, and that also serve to bring consumers back for repeat purchase and product loyalty.”
Some oil producers have tackled the clean-label issue by changing the fatty acid profile of the actual oil-producing plants. They are using traditional plant-breeding techniques to develop a new generation of non-GMO oils, without the need for preservatives.
These breeding techniques aim to elevate levels of the more stable fatty acids, such as oleic acid and monounsaturated fats, and to lower the levels of less stable fatty acids and polyunsaturated fats. The resulting oil is inherently more stable and more appealing to consumers because it is produced from non-GMO plants.
Other suppliers are taking a totally different tack by looking for completely new sources, such as algae, for better-for-you oils. Algae produce a range of lipids, including one that contains as much as 94% monounsaturated fats and only 4% saturated fat. The oil, which has only been commercially available for a few years, has a smoke point of 252˚C (485˚F), thus removing any concerns about burning foods or about creating free radicals, which can be carcinogenic. Its fatty acid makeup provides emulsifying properties, making algal oil ideal for egg-free vegan baking, while its buttery flavor favors its use as a butter replacer.
Yet others are exploring new ways to enhance shelflife and fry life. Assam tea extract, made up mostly of catechins and antioxidants, is being tested in rice bran oils to replace synthetic antioxidants without sacrificing taste and texture.
Oils on Trend
The move to use different fats and oils is growing by leaps and bounds, with everything from ahi flower oil to pumpkin seed oil finding its way into new products. Some of the food oils starting to make a significant footprint in the industry include rice bran oil, red palm oil, berry seed oils, mustard seed oil, and pumpkin seed oil.
Rice bran oil is a byproduct of rice processing and is derived from rice bran by steam extraction. Rice bran oil is valued in foodservice, particularly in Chinese cooking and other cuisines that involve stir-frying at high heat, because of its mild flavor and high heat tolerance. From a practical standpoint, its high smoke point allows it to be heated to 232˚C (450˚F) during stir-frying before it burns or smokes, without oil-logging the ingredients.
Rice bran oil is rich in tocotrienols and phytosterols, and is one of the most abundant natural sources of oryzanols. These are essentially plant sterols esterified to ferulic acid, believed to have additional bioactivity and shown to have hypocholesterolemic influence via selective decrease of LDL.
The Chipotle Mexican Grill Inc. restaurant chain removed genetically modified ingredients from its portfolio and replaced all soy-derived oil that could have been genetically modified with rice bran oil in its fajita vegetables and sofritas.
The announcement of the replacement by Chipotle founder Steve Ells thrust rice bran oil into the foodie spotlight as a “safer” and “better for the planet” specialty oil. Since then, other food companies have jumped on the bandwagon and are using rice bran oil in their formulations. For example, Boulder Canyon Authentic Foods Inc. proudly displays “Rice Bran Oil” on its Rice Bran Oil-Roasted Jalapeño potato chips.
Health-conscious consumers are discarding less healthy commodity oils for cold-pressed edible seed oils from cranberry, raspberry, pumpkin, cherry, and sea buckthorn. These berries have excellent nutrient profiles and offer options for those seeking to increase intake of beneficial fats but not through fried foods.
Berry seed oils are generally heat-sensitive and not suitable for cooking, but they are attracting interest as components in dressings and marinades.
Seeds of strawberries, raspberries, blackcurrant, and even apples are a rich source of polyenoic fatty acids. These are not synthesized in the human body and must be supplied through diet. The native oils are rich in tocochromanols (a form of tocotrienols) and phytosterols, and have been used largely in pharmaceuticals and cosmetics. Recently, they have been introduced in food applications and are prized for their potential nutraceutical effects.
Cold-pressed oil from pumpkin seeds, a traditional food valued for cardioprotective and antihypertensive effects, is gathering an enthusiastic following among both boutique and large-scale food manufacturers. Pumpkin seeds, a byproduct of pumpkin processing, yield an oil that is rich in vitamins A and E, omega 3 and 6 fatty acids, zinc, tryptophan, and a host of potent antioxidants.
Stöger Oils Gmbh, like La Tourangelle, toasts pumpkin seeds before expeller-pressing the oil for an additional layer of flavor and aroma that brings a rich, nutty taste to salad dressings and spreads. Although pumpkin seed oil has a higher smoke point than berry seed oils, heating is not recommended, as it can cause the oil to become bitter.
Cranberry seed oil is a particularly rich source of polyunsaturated fatty acids, with up to 35% alpha-linolenic acid and a ratio of omega-6 to omega-3 fatty acids ranging between 1.2:1 and 2:1. (The typical American diet contains a much higher ratio of omega-6 to omega-3 fats, which is believed to promote inflammation and chronic disease.) Additionally, cranberry seed oil is high in anthocyanins, colorful flavonoids linked to a reduced risk of heart disease.
Hot Oil Futures
The genus Solanum contains approximately 1,500 to 2,000 species, including tomatoes, eggplant, peppers, and potatoes. Historically, eggplant and other Solanum species have not been cultivated for their seed or seed oil, nor have they been bred or selected with seed yield or seed oil characteristics as a goal.
Although tomato and pepper seeds are regarded as a low-value byproduct of tomato and pepper processing, they show tremendous potential in producing oil with high antioxidant capability.
The high content of unsaturated fatty acids, especially linoleic acid, in tomato seeds makes these and related seed oils a good source of edible oil. They also maximize the economic value of tomatoes and protect the environment. Seeds, which are 20% oil, constitute roughly 3-5% of the 44 million tons of tomatoes that go into processed foods.
Both tomato seed oil and chili seed oil are gaining popularity with product formulators because these products have complex flavor profiles and the enticing aroma of their source. Moreover, the positive flavors and aromas can be put to good advantage enhancing packaged foods and lending a sense that they were freshly made. The amounts needed are miniscule, and the ingredients typically appear on labels as “natural flavors” or “spices” for proprietary and competitive advantage.
Plants represent a veritable cornucopia of specialty oils, some of which are used extensively in some parts of the world, while others are being studied for consumer appeal and economic viability. Mustard seed oil, used throughout India and in the Middle East for cooking and pickling, is also being used increasingly in Western formulations to add zest, taste, heat, and aromatic dimensions that cannot be obtained from other ingredients. Innovators are turning to specialty oils like mustard seed oil and cherry seed oil for that unique appeal and marketable advantage.
The demand for specialty oils, especially those from vegetables, is shaped by the health and wellness trend, sustainable sourcing, shorter supply chains, and consumer interest in exotic products. The prepared foods sector is only now opening to emerging specialty oils, and is likely to increase usage dramatically when issues of food safety and trans-fatty acid replacement come to light.
This trend is already happening and is especially strong in salad dressings and snacks, where the high-end segment is largest. Expect other food categories to follow.
Originally appeared in the May, 2017 issue of Prepared Foods as Liquid Gold.
Back in the Spotlight
Safflower oil was popular decades ago but had been elbowed out somewhat by other commodity oils. Of late, it seems this healthful plant oil is making a comeback. Safflower plants produce high levels of arachidonic acid (ARA), a high-value, specialty nutritional lipid compound that is gaining ground in global consumer markets. ARA is an omega-6 fatty acid that, like its omega-3 counterpart, plays a critical role in neural and visual development of infants. As one of the most abundant fatty acids in the brain, adequate levels of ARA are critical to neurological health. In infant nutrition products, ARA is used as a functional ingredient to provide developmental benefits similar to breastfeeding. ARA also has been reviewed and supported by the FDA, the Food and Agriculture Organization of the UN, and WHO.
Safflower oil provides a renewable and sustainable source of nutritionally important ARA. Since sunlight provides all the energy needed to make ARA in safflower seed oil, ARA production is also cost-effective in contrast to other commercial methods.