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Fat hydrogenation
Fat hydrogenation
Fat hydrogenation
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Fat hydrogenation is the process of combining unsaturated fat with hydrogen in order to partially or completely convert it into saturated fat. Typically this hydrogenation is done with liquid vegetable oils resulting in solid or semi-solid fats.[1]

Changing the degree of saturation of the fat changes some important physical properties, such as the melting range, which is why liquid oils become semi-solid. Solid or semi-solid fats are preferred for some baked goods such as biscuits and pie dough because how the fat mixes with flour produces a more desirable, crumbly texture in the baked product. Because partially hydrogenated vegetable oils are cheaper than animal fats, are available in a wide range of consistencies, and have other desirable characteristics such as increased oxidative stability and longer shelf life, they are the predominant fats used as shortening in most commercial baked goods.

The process is typically carried out at very high pressure, with the help of a nickel catalyst that is removed from the final product.

Process

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Hydrogenating vegetable oil is done by raising a blend of vegetable oil and a metal catalyst, typically nickel, in near-vacuum to very high temperatures, and introducing hydrogen. This causes the carbon atoms of the oil to break double-bonds with other carbons. Each carbon atom becomes single-bonded to an individual hydrogen atom, and the double bond between carbons can no longer exist.

The desirable (left) and undesirable pathways for partial hydrogenation of an unsaturated fat. Elaidic acid is a trans fat with negative health effects.

Full hydrogenation results in the conversion of all of the unsaturated fats into saturated fats by transforming all of the double bonds in the fat into single bonds. Partial hydrogenation reduces some, but not all, of the double bonds by the partial replacement with single bonds. The degree of hydrogenation is controlled by restricting the amount of hydrogen, reaction temperature and time, and the catalyst.[2]


History

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Wilhelm Normann patented the hydrogenation of liquid oils in 1902
Cover of original Crisco cookbook, 1912

Nobel Prize laureate Paul Sabatier worked in the late 1890s to develop the chemistry of hydrogenation.[3] Whereas Sabatier considered hydrogenation of only vapors, the German chemist Wilhelm Normann showed in 1901 that liquid oils could be hydrogenated, and patented the process in 1902.[4][5] Normann's hydrogenation process made it possible to stabilize affordable whale oil or fish oil for human consumption, a practice kept secret to avoid consumer distaste.[6] During the years 1905–1910, Normann built a fat-hardening facility in the Herford company. At the same time, the invention was extended to a large-scale plant in Warrington, England, at Joseph Crosfield & Sons, Limited. It took only two years until the hardened fat could be successfully produced in the plant in Warrington, commencing production in late 1909. The initial year's production totalled nearly 3,000 tonnes.[6] In 1909, Procter & Gamble acquired the United States rights to the Normann patent;[7] in 1911, they began marketing the first hydrogenated shortening, Crisco (composed largely of partially hydrogenated cottonseed oil). Further success came from the marketing technique of giving away free cookbooks in which every recipe called for Crisco.

Before 1910, dietary fats in industrialized nations consisted mostly of butterfat, beef tallow, and lard. During Napoleon's reign in France in the early 19th century, a type of margarine was invented to feed troops using tallow and buttermilk. Soybeans began to be imported into the U.S. as a source of protein in the early 20th century, resulting in an abundance of soybean oil as a by-product that could be turned into a solid fat, thereby addressing a shortage of butterfat. With the advent of refrigeration, margarines based on hydrogenated fats presented the advantage that, unlike butter, they could be taken out of a refrigerator and immediately spread on bread. Some minor changes to the chemical composition of hydrogenated fats yielded superior baking properties compared to lard. As a result of these factors, margarine made from partially hydrogenated soybean oil began to replace butterfat. Partially hydrogenated fat such as Crisco and Spry, sold in England, began to replace butter and lard in baking bread, pies, cookies, and cakes in 1920.[8]

Production of partially hydrogenated fats increased steadily in the 20th century as processed vegetable fats replaced animal fats in the U.S. and other Western countries. At first, the argument was a financial one due to the lower costs of margarines and shortenings compared to lard and butter, particularly for restaurants and manufacturers. However, during the 1980s regulators, physicians, nutritionists, popular health media, educational curricula and cookbooks began to promote diets low in saturated fats for health reasons. Advocacy groups in the U.S. responded by demanding the replacement of saturated animal and tropical fats with vegetable alternatives. The Center for Science in the Public Interest (CSPI) campaigned vigorously against the use of saturated fats by corporations, including fast-food restaurants, endorsing trans fats as a healthier alternative. The National Heart Savers Association took out full page ads in major newspapers, attacking the use of beef tallow in McDonald's French fries. They urged multinational fast-food restaurants and food manufacturers to switch to vegetable oils, and almost all targeted firms responded by replacing saturated fats with trans fats.[9][10][11]

Since then the food industry has moved away from partially hydrogenated fats in response to the health concerns about trans fats, labeling requirements, and removal of trans fats from permitted food additives.[12][13][14] They have been replaced with fully hydrogenated fats, vegetable oils that are naturally higher in saturated fat and therefore more solid at room temperature, such as palm oil and coconut oil, and interesterified fats, which cannot result in the formation of trans fats.[citation needed]

Issues

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Main article: trans fat

Cis–trans isomerization of some of the remaining unsaturated carbon bonds to their trans isomers during the partial hydrogenation process produces trans fat, which can increase the risk of cardiovascular problems.[15] [16] The conversion from cis to trans bonds is favored because the trans configuration has lower energy than the natural cis one. At equilibrium, the trans/cis isomer ratio is about 2:1.

See also

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Fat hydrogenation

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from Grokipedia
Fat hydrogenation is a catalytic chemical process that adds hydrogen gas to the carbon-carbon double bonds of unsaturated fatty acids in liquid vegetable oils, converting them into more saturated, semi-solid or solid fats with improved stability and functionality for food applications. Invented by German chemist Wilhelm Normann in 1901 and patented in Britain and Germany by 1903, the process addressed the need for affordable, plant-based alternatives to scarce animal fats like lard and butter, enabling the mass production of shortenings, margarines, and baking fats. Procter & Gamble commercialized hydrogenated cottonseed oil as Crisco shortening in 1911, which rapidly gained popularity for its versatility in cooking and baking, contributing to the decline of traditional animal fats in processed foods. While full hydrogenation produces stable saturated fats without altering melting points dramatically, partial hydrogenation—widely used for texture control—generates trans fatty acids as byproducts, which peer-reviewed studies have causally linked to adverse health effects including elevated LDL cholesterol, endothelial dysfunction, and heightened risk of cardiovascular disease and premature mortality. These findings, emerging prominently from the 1990s onward, prompted regulatory actions such as bans on partially hydrogenated oils in the United States by the FDA in 2015 and similar restrictions globally, driving industry shifts toward interesterification and other fat modification techniques.

Chemical and Technical Foundations

Definition and Basic Mechanism

Fat hydrogenation is the process of adding hydrogen to the carbon-carbon double bonds in unsaturated fatty acids within triglycerides, thereby converting liquid oils into semi-solid or solid fats with higher melting points and greater oxidative stability. This reaction reduces the degree of unsaturation, altering physical properties to suit applications like shortenings and margarines. The basic mechanism follows the Horiuti-Polanyi model of heterogeneous catalytic . Molecular adsorbs and dissociates into atomic on the catalyst surface, typically ; the unsaturated chain then adsorbs via its , allowing sequential addition of atoms. Half-hydrogenated intermediates form, which can either fully saturate by adding a second or desorb after , shifting cis double bonds to trans configurations under partial conditions. The process occurs at temperatures of 100–250 °C and pressures influencing and rate, with the controlled to achieve desired saturation levels.

Types of Hydrogenation: Partial versus Full

Partial of oils involves the controlled addition of to unsaturated fatty acids under catalytic conditions, typically using catalysts at elevated temperatures and pressures, resulting in a semi-solid consistency suitable for products like and shortenings. This process reduces polyunsaturated fatty acids to monounsaturated or less saturated forms but often leads to the of cis double bonds to trans configurations, producing trans fatty acids (TFAs) in concentrations up to 40-50% depending on reaction conditions. The partial nature allows for desired plasticity and oxidative stability while destroying labile fatty acids like to extend . In contrast, full hydrogenation saturates all double bonds in the fatty acids, yielding fully saturated fats that are solid and hard at without forming trans isomers. This complete reaction requires sufficient and appropriate conditions to eliminate unsaturation entirely, producing from oleic and linoleic precursors in oils like or palm. Fully hydrogenated fats lack the TFA content associated with partial processes and are often blended with liquid oils to achieve texture without health concerns linked to trans fats, though they contribute to higher levels.
AspectPartial HydrogenationFull Hydrogenation
Saturation LevelIncomplete; retains some double bonds, often as trans isomersComplete; all double bonds saturated
TFA FormationSignificant (e.g., 20-50% in products); due to cis-to-trans isomerizationNone; no isomerization occurs
Physical PropertiesSemi-solid, plastic fats for spreads and Hard, brittle solids requiring blending for usability
Primary Applications, shortenings for texture and stabilityBase for interesterified fats or additives in formulations without TFAs
Health ImplicationsAssociated with elevated LDL from TFAsPrimarily saturated fats; no trans-related risks
The distinction arises from reaction control: partial hydrogenation is selectively stopped to preserve functionality, whereas full hydrogenation proceeds to exhaustion, prioritizing saturation over intermediate geometries. Empirical from analytical methods like confirm higher TFA levels in partially hydrogenated oils compared to their fully hydrogenated counterparts.

Historical Context

Invention and Early Commercialization

German chemist Wilhelm Normann developed the process of catalytic for converting liquid vegetable and animal oils into solid fats in 1901, using finely divided as a to add across carbon-carbon double bonds in unsaturated fatty acids. This breakthrough enabled the production of stable, semi-solid fats from inexpensive liquid oils such as , , and , which previously spoiled quickly or remained liquid at . Normann filed a in on August 14, 1902, for the method, receiving German Patent 141,029 on July 13, 1903, titled "Process for the Reduction of Unsaturated Compounds of the Fatty Acid Series." The technology's early commercialization began in when British soap manufacturer Joseph Crosfield & Sons acquired rights to Normann's patent and established the world's first industrial fat hydrogenation plant in , , in 1907, producing hardened oils primarily for and manufacturing. By 1909, annual production reached nearly 3,000 tonnes, with applications expanding to edible fats to stabilize low-cost oils for and shortenings. In the United States, secured the American rights to Normann's patent in 1909 from Crosfield and developed the first fully hydrogenated vegetable , , using partially hydrogenated . Launched in June 1911, was marketed as a pure, economical alternative to animal-based and , with an of 65-82 indicating partial hydrogenation for spreadable consistency and extended . Initial sales were promoted through recipe books and demonstrations, achieving rapid adoption in and due to its high and plasticity. Early adoption faced technical challenges, including and inconsistent solidity, but refinements in catalyst preparation and reaction conditions by 1915 improved yield and purity, facilitating broader industrial scaling. By the late , hydrogenated fats comprised a significant portion of production, with U.S. output exceeding 100 million pounds annually by 1920, driven by wartime shortages of animal fats.

Widespread Adoption in the 20th Century Food Industry


Partial hydrogenation of vegetable oils gained traction in the food industry shortly after Wilhelm Normann's 1902 patent, with the first large-scale commercial plant established in England by Joseph Crosfield & Sons in 1906. Procter & Gamble acquired U.S. rights to the process in 1909 and introduced Crisco in June 1911 as the first hydrogenated vegetable shortening, derived primarily from cottonseed oil, marketed as a stable, economical alternative to animal-based lard and butter. This innovation addressed limitations of liquid oils by producing semi-solid fats suitable for baking and frying, enabling mass production of consistent food products. By 1910, partial hydrogenation was integrated into margarine manufacturing, transforming liquid vegetable oils into spreadable forms and facilitating the shift from animal fats like . In the U.S., vegetable appeared commercially in 1914, with early incorporations of in both and by 1912. Companies such as (later ) adopted the process to harden oils for , enhancing texture and shelf life while reducing reliance on costly or scarce animal derivatives. shortages of animal fats accelerated domestic vegetable oil processing, with U.S. imports surging to 264.9 million pounds in 1917, much of it directed toward hydrogenated products. The interwar period saw expanded industrial implementation, as hydrogenation enabled flavor stability and resistance to rancidity in processed foods. By the 1930s, advancements like continuous solvent extraction by Archer Daniels Midland in 1934 supported larger-scale production of hydrogenatable oils such as soybean. During World War II, further animal fat rationing propelled vegetable shortenings; soybean oil overtook cottonseed oil as the primary U.S. shortening ingredient by 1944, with 1,245.8 million pounds used. Postwar economic growth and the rise of convenience foods entrenched hydrogenated fats in baked goods, snacks, and frying applications, with margarine availability per capita rising as butter declined from 16.4 pounds in 1942 to 5.0 pounds by 1972. By mid-century, partially hydrogenated oils had become staples in the U.S. food supply, comprising key components in an estimated 75% of processed soy oil uses for shortenings and margarines.

Industrial Applications and Functional Benefits

Process Implementation in Manufacturing

In industrial , fat hydrogenation typically occurs in closed reactors designed for high-pressure operation, where refined oils such as or are processed to achieve desired physical properties like solidity and oxidative stability. The process begins with preheating the purified oil to approximately 130–150°C to initiate the reaction efficiently while minimizing side . A supported , often activated and encapsulated in hydrogenated for handling and dispersion, is introduced at loadings of 0.005–0.02% by weight relative to the oil, serving as the primary agent to facilitate addition across carbon-carbon double bonds. gas is then sparged into the under pressures ranging from 1 to 5 bar (100–500 kPa), with vigorous mechanical agitation or gas dispersion ensuring intimate contact between the gas, , and oil phases. Reaction conditions are maintained at temperatures of 150–200°C and monitored closely via periodic sampling for (IV), which quantifies remaining unsaturation and guides the extent of partial or full to target specific melting points, such as 30–40°C for shortenings. Batch processes predominate in smaller-scale operations, lasting 1–4 hours depending on feedstock and endpoint, while continuous systems using fixed-bed or reactors enable higher throughput in large refineries. Upon completion, the spent is recovered through , often under inert atmosphere to prevent oxidation, followed by bleaching with activated clay to remove color bodies and residual metals, and deodorization via steam stripping at 220–260°C under . These downstream steps ensure product purity, with regeneration or disposal managed to comply with environmental standards, as leaching must be minimized below regulatory limits like 0.2 ppm in fats.

Advantages for Product Stability and Economics

Partial hydrogenation enhances the oxidative stability of oils by saturating a portion of their carbon-carbon double bonds, thereby reducing susceptibility to rancidity and extending in products such as shortenings, margarines, and fried foods. This process converts polyunsaturated fatty acids, which are prone to auto-oxidation, into more stable mono- or di-unsaturated forms, minimizing off-flavors and odors during storage and cooking. For instance, hydrogenated exhibits significantly lower peroxide values under accelerated oxidation tests compared to its non-hydrogenated counterpart, preserving product quality for months longer. The resulting fats achieve higher melting points—often 30–40°C for partially hydrogenated variants—enabling semi-solid textures at that improve spreadability, creaming in , and fry stability without the need for or additives. This functional plasticity mimics expensive animal fats like or while offering superior performance in cold conditions, such as easier spreading of directly from the refrigerator. In industrial frying, hydrogenated fats resist breakdown at high temperatures (up to 180–200°C), reducing foam formation and oil absorption in foods like doughnuts and . Economically, hydrogenation leverages abundant, low-cost liquid vegetable oils—such as or , priced at fractions of s—to produce versatile solid shortenings, slashing raw material costs by up to 50% in early 20th-century formulations like . The process requires modest capital investment in catalysts and high-pressure reactors, yielding high-volume output with consistent profiles that standardize product quality across batches, minimizing waste from variability in natural fats. By enabling year-round production without seasonal shortages, it supported scalable , with global partially hydrogenated oil use exceeding millions of tons annually by the mid-20th century to meet demand for baked goods and .

Health and Safety Considerations

Formation of Trans Fatty Acids

Partial of vegetable oils entails the controlled addition of gas to carbon-carbon double bonds in unsaturated fatty acids, typically catalyzed by finely divided under temperatures of 120–220 °C and pressures of 1–5 atmospheres. This aims to convert liquid oils into semi-solid fats with enhanced oxidative stability and desirable melting properties for food applications such as margarines and shortenings. However, incomplete saturation of double bonds leads to cis-trans , generating trans fatty acids as a . The trans configuration arises because the catalyst surface facilitates temporary half-hydrogenated intermediates, allowing around the weakened bond and desorption in the more thermodynamically stable trans geometry. The extent of trans fatty acid formation correlates with process variables including reaction temperature, hydrogen partial pressure, catalyst activity, and the targeted. Higher temperatures and lower hydrogen pressures promote greater due to prolonged intermediate lifetimes on the catalyst, with partially hydrogenated often containing 20–50% trans isomers by weight. migration accompanies , shifting positions and further diversifying the profile, though positional isomers do not alter the cis/trans designation. In contrast, complete minimizes trans formation by fully saturating bonds before significant accumulates. Industrial trans fats from partial differ structurally from naturally occurring trans fats in products, which are predominantly isomers like , whereas hydrogenated trans fats are mainly (trans-9-octadecenoic acid). This distinction arises from the catalytic mechanism favoring isolated trans monounsaturates over the biohydrogenation pathways in microbes. Quantitatively, partial hydrogenation can yield up to 40% trans content in optimized processes for plasticity, though selective catalysts like reduce this to under 10% in some formulations.

Empirical Evidence on Cardiovascular Risks

Trans fatty acids (TFAs) produced via partial hydrogenation of vegetable oils elevate low-density lipoprotein (LDL) cholesterol levels while reducing high-density lipoprotein (HDL) cholesterol, thereby adversely affecting the total-to-HDL cholesterol ratio, a established predictor of coronary heart disease (CHD) risk. This lipid profile shift mirrors or exceeds effects observed with saturated fatty acids, based on controlled feeding studies where TFA consumption directly worsened these biomarkers compared to cis-unsaturated fats. Prospective cohort studies consistently link higher TFA intake or levels to increased CHD incidence and mortality. A 2015 meta-analysis of 32 observational studies found that each 2% increment in energy from total TFA intake correlated with a 23% higher of CHD events ( [RR] 1.23, 95% CI 1.08-1.41), alongside elevated CHD mortality (RR 1.28, 95% CI 1.09-1.50) and all-cause mortality (RR 1.34, 95% CI 1.16-1.56). Similarly, a nested case-control within the and Health Professionals Follow-up Study demonstrated that erythrocyte membrane TFA content predicted CHD independently of other factors, with higher levels associated with up to 50% greater . Randomized controlled trials (RCTs) directly isolating industrial TFAs are scarce, as historical interventions often confounded them with polyunsaturated fats like from partially hydrogenated sources. The Diet Heart Study (1966-1973), a secondary prevention RCT, replaced saturated fats with -rich safflower oil and containing TFAs, resulting in higher all-cause mortality (17.6% vs. 11.8% in controls; [HR] 1.62, 95% CI 1.00-2.64), CHD mortality (16.3% vs. 10.1%; HR 1.70, 95% CI 1.03-2.80), and cardiovascular mortality despite reductions. The Coronary Experiment (1968-1973), involving over 9,000 participants, substituted saturated fats with (high in ) and , lowering serum by 13.8% in the intervention group but yielding no mortality benefit and a 22% higher CHD death rate per 30 mg/dL reduction in subgroup analyses. These findings challenge assumptions that TFA-induced alone drives outcomes, as lowering did not translate to event reductions and may indicate oxidative or inflammatory harms from excess n-6 polyunsaturated fats. Post-marketing ecological data from trans fat restrictions, such as in New York counties implementing bans from 2007, showed a 6.2% decline in hospital admissions for and (2002-2012), though remains debated due to concurrent trends in and use. Modeling studies estimate that replacing partially hydrogenated oils with non-hydrogenated alternatives could avert 17,134-72,000 CHD deaths annually in the U.S., based on observed effects and equations, but these rely on assumptions from observational data rather than direct trial evidence. Overall, while and associative evidence supports elevated cardiovascular from hydrogenated fat-derived TFAs, the paucity of unconfounded RCTs limits , with historical trials highlighting potential paradoxes in substituting them for saturated fats.

Critiques of Trans Fat Health Narratives and Comparative Risks

Critiques of the dominant health narratives surrounding industrial trans fatty acids (TFAs) from partial emphasize distinctions between TFA isomers and question the uniformity of their risks, as well as the relative emphasis placed on them versus other dietary components. While , a predominant industrial TFA, has been linked to adverse lipid profiles in randomized controlled trials, elevating (LDL) and reducing (HDL) , ruminant TFAs such as —found in and ruminant meats—do not exhibit these effects and may improve HDL levels. A 2015 German intervention study demonstrated that supplementation with vaccenic acid raised HDL without increasing LDL, suggesting potential cardiovascular benefits absent in industrial variants. This isomer-specific differentiation challenges narratives portraying all TFAs as equivalently hazardous, as early messaging often failed to parse natural versus synthetic sources, potentially overstating risks from low-level ruminant exposures that constitute up to 50% of TFA intake in some diets. Epidemiological evidence associating industrial TFAs with (CVD) relies heavily on observational cohorts, which critics argue are prone to by overall diet quality, as TFAs correlate with processed consumption rather than isolated causation. Short-term randomized trials confirm unfavorable changes from industrial TFAs but lack long-term outcome on hard endpoints like , limiting causal inference. A 2015 meta-analysis of prospective studies reported a 34% higher all-cause mortality risk per 2% increment in energy from trans fats, yet the population-attributable fraction remains modest given historical U.S. intakes of 1-2% of calories, equating to fewer than 3,000 preventable CVD deaths annually pre-phase-out. Critics contend this pales against major modifiable risks like (responsible for over 400,000 U.S. deaths yearly) or sedentary behavior, yet drove disproportionate regulatory fervor, possibly amplified by institutional biases favoring low-fat paradigms that initially promoted hydrogenated margarines as alternatives. Comparatively, saturated fats—often conflated with TFAs in simplified guidelines—show no association with increased CVD, mortality, or risk in the same , with relative risks near unity across cohorts totaling over 300,000 participants. For instance, highest versus lowest quartiles yielded hazard ratios of 1.00 for all-cause mortality and 1.02 for CVD events, contrasting trans fats' elevated risks but underscoring that replacement strategies emphasizing polyunsaturated fats (PUFAs) over saturates may not yield net benefits, as some PUFAs promote oxidation and inflammation in causal models. Post-ban substitutions, including (high in saturates) or interesterified fats, have raised concerns over unproven long-term safety, with animal studies indicating from the latter. These observations fuel arguments that trans fat narratives, while grounded in data, undervalue contextual risks and prioritize marginal gains over holistic dietary realism, potentially diverting focus from carbohydrate quality or total energy balance as stronger CVD determinants.

Regulatory Responses and Phase-Outs

National and International Bans

became the first country to implement a national ban on industrially produced trans fats in foods, effective June 1, 2003, limiting their content to 2 grams per 100 grams of fat. This measure targeted partially hydrogenated oils, the primary source of such trans fats, and was enacted following epidemiological evidence linking them to elevated rates. In the United States, the (FDA) issued a final determination on June 17, 2015, revoking the (GRAS) status of partially hydrogenated oils (PHOs), mandating their phase-out from most foods by June 18, 2018. Compliance was extended for certain uses, with a direct final rule effective December 22, 2023, fully prohibiting PHOs without prior approval. Similar bans followed in (2018), (2023), and other nations, often aligning with voluntary industry reformulations. At the international level, the (WHO) released its REPLACE action package on May 14, 2018, providing a framework for countries to eliminate industrially produced trans-fatty acids from the global food supply by 2023. Progress reports indicate that by 2023, 43 countries covering 2.8 billion people had adopted best-practice policies, such as bans or limits below 2% of total fat content. In the , Regulation () 2019/649 imposed a cap of 2 grams of industrially produced trans fats per 100 grams of fat (excluding naturally occurring sources) effective April 1, 2021, harmonizing standards across member states. These efforts reflect a coordinated response to evidence of trans fats' atherogenic effects, though implementation varies by enforcement mechanisms and baseline dietary exposures.

Compliance Challenges and Industry Adaptations

The U.S. Food and Drug Administration's 2015 determination that partially hydrogenated oils (PHOs) were no longer prompted significant compliance hurdles for manufacturers, including the need to reformulate thousands of products to eliminate trans fatty acids while preserving functionality such as texture, , and . Initial compliance deadlines were set for June 18, 2018, but extended to January 1, 2020—and further for certain uses until January 1, 2021—due to the technical difficulties in replicating PHOs' oxidative stability and plasticity without introducing excessive saturated fats or compromising product quality. Reformulation required extensive , with challenges amplified by the requirement for stability testing under accelerated conditions to ensure equivalent performance in baked goods, fried foods, and spreads. Economic pressures compounded these issues, as the total costs encompassed ingredient sourcing shifts, process modifications, and relabeling, with the FDA estimating average relabeling expenses at approximately $1,400 per stock-keeping unit for changes implemented within three years. disruptions arose from the phase-out of PHO production, forcing reliance on new suppliers and potentially higher-cost alternatives, while smaller manufacturers faced disproportionate burdens due to limited R&D resources compared to larger firms. In , Denmark's pioneering 2003 capping industrially produced trans fats at 2 grams per 100 grams of allowed a nine-month transition, during which some and producers encountered difficulties but ultimately complied without widespread exemptions. The EU's 2019 directive imposing a similar 2-gram limit highlighted ongoing monitoring inconsistencies and analytical method variations as barriers to uniform enforcement across member states. Industry adaptations primarily involved substituting PHOs with blends of fully hydrogenated oils, palm-based fats, and oils to maintain solidity and resistance to rancidity, often requiring adjustments in endpoints or techniques. By 2018, many U.S. manufacturers had proactively reformulated over 80% of affected products ahead of deadlines, reducing content while in some cases lowering overall levels through optimized oil combinations. These shifts increased demand for tropical oils like palm, which offered similar melting profiles but introduced supply volatility tied to global commodity prices. Larger food companies invested in proprietary emulsifiers and high-oleic oils to mitigate functionality gaps, though hidden costs from reduced efficiency in non-PHO systems—such as altered yields—persisted as a long-term challenge. Overall, compliance fostered innovation in fat chemistry, with empirical data indicating successful elimination in compliant markets without equivalent rises in total unhealthy fat intake when managed through targeted reformulations.

Alternatives and Emerging Developments

Traditional Substitutes like Interesterification

Interesterification involves the rearrangement of s within triacylglycerols, the primary components of dietary fats, to modify physical properties such as and solidity without introducing trans fatty acids. This process serves as a key alternative to partial , which historically produced trans fats during the creation of semi-solid fats for products like and shortenings. Chemical interesterification employs alkaline catalysts, such as sodium methanolate, to randomize fatty acid positions, while enzymatic methods use lipases under milder conditions to achieve targeted rearrangements. Adopted widely in the following regulatory pressures against trans fats, interesterification enables the production of stable, spreadable fats from liquid oils like palm or blends, mimicking the functionality of fats. For instance, interesterified palm products have been utilized to formulate zero-trans shortenings, reducing reliance on while maintaining plasticity for and applications. Enzymatic interesterification, though costlier, offers advantages including lower formation and simpler purification, making it preferable for high-value products like fat substitutes. Despite these benefits, chemical interesterification incurs yield losses from free fatty acid formation and soap by-products, potentially increasing processing costs compared to hydrogenation. Enzymatic variants mitigate some issues but remain economically challenging due to enzyme expenses. Other traditional substitutes, such as fractionation to separate solid stearin fractions or blending with fully hydrogenated oils (which eliminate double bonds entirely, avoiding trans formation), complement interesterification but often require combination for optimal texture. Overall, interesterification has facilitated industry compliance with trans fat restrictions, as seen in reformulated margarines and confectionery fats since the early 2000s.

Novel Technologies and Future Prospects

Plasma-assisted represents a promising non-thermal approach for modifying edible oils, enabling partial without formation. Techniques such as high-voltage atmospheric cold plasma, microwave plasma, and dielectric-barrier discharge plasma have been applied to oils, achieving saturation of double bonds at low temperatures while producing negligible trans isomers. For instance, cold plasma treatment of with gas has transformed liquid oils into solid products with levels below detectable limits, contrasting with traditional methods that yield up to 40% . These processes leverage ionized gas to activate , bypassing high-pressure and catalyst-heavy conditions of conventional . Electrocatalytic hydrogenation offers another low-trans alternative, utilizing electrochemical cells to hydrogenate oils at ambient temperatures and pressures. Research demonstrates over 80% reduction in trans fatty acids compared to gaseous , employing anions as hydrogen donors and supported metal catalysts like . In trials, this method yielded partially hydrogenated products with trans content as low as 5-10%, suitable for food applications requiring plasticity without health risks. catalysts, such as nanoparticles, further enhance selectivity toward cis-monounsaturated fats, minimizing both trans and byproducts. Supercritical fluid hydrogenation employs solvents like or CO2 to create homogeneous reaction phases, improving and efficiency for selective reduction of polyunsaturated fatty acids. Studies on using 2% Pd/C in achieved high conversion with low trans formation, potentially under 10% trans-C18:1. reactors integrated with catalysts have similarly reduced trans fats to 2-5% in continuous processes. Future prospects hinge on overcoming scalability barriers, such as reactor design for industrial throughput and recyclability, to integrate these technologies into commercial edible fat production. While plasma and electrocatalytic methods show trans-free potential, economic viability requires optimization for energy efficiency and byproduct control; supercritical approaches may complement by enabling precise profiling for tailored shortenings. Ongoing research into hybrid systems, like plasma-enhanced , could standardize low-trans , supporting regulatory demands for zero industrially produced trans fats without relying on increases.

References

  1. https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_%28Biological_Chemistry%29/Lipids/Fatty_Acids/Hydrogenation_of_Unsaturated_Fats_and_Trans_Fat
  2. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/hydrogenation
  3. https://www.aocs.org/resource/the-battle-over-hydrogenation-1903-1920/
  4. https://www.aocs.org/resource/wilhelm-normann-1870-1939/
  5. https://msutoday.msu.edu/news/2019/12/how-crisco-toppled-lard
  6. https://pmc.ncbi.nlm.nih.gov/articles/PMC3551118/
  7. https://pmc.ncbi.nlm.nih.gov/articles/PMC8535577/
  8. https://www.sciencedirect.com/science/article/abs/pii/S0021915009002081
  9. https://www.scientificamerican.com/article/scientific-case-for-banning-trans-fats/
  10. https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-13-1139
  11. https://chem.libretexts.org/Bookshelves/Biological_Chemistry/Supplemental_Modules_(Biological_Chemistry)/Lipids/Fatty_Acids/Hydrogenation_of_Unsaturated_Fats_and_Trans_Fat
  12. https://www.aocs.org/resource/hydrogenation-in-practice/
  13. https://www.aocs.org/resource/hydrogenation-mechanism/
  14. https://pmc.ncbi.nlm.nih.gov/articles/PMC7495778/
  15. https://pmc.ncbi.nlm.nih.gov/articles/PMC2921725/
  16. https://www.sciencedirect.com/topics/neuroscience/hydrogenated-vegetable-oil
  17. https://www.canr.msu.edu/news/fats_the_good_the_bad_and_the_ugly
  18. https://nutrition.ucdavis.edu/outreach/nutr-health-info-sheets/pro-transfat
  19. https://books.rsc.org/books/edited-volume/1074/chapter/895070/Catalytic-Hydrogenation-of-Vegetable-Oils
  20. https://pmc.ncbi.nlm.nih.gov/articles/PMC10298259/
  21. https://www.soyinfocenter.com/books/227
  22. https://learncheme.com/wp-content/uploads/Prausnitz/Health/HydrogenatingDietaryOils.pdf
  23. https://www.westonaprice.org/health-topics/modern-foods/the-rise-and-fall-of-crisco/
  24. https://www.soyinfocenter.com/pdf/227/Hydr.pdf
  25. https://www.smithsonianmag.com/innovation/how-crisco-made-americans-believers-industrial-food-180973845/
  26. https://pmc.ncbi.nlm.nih.gov/articles/PMC2769584/
  27. https://pmc.ncbi.nlm.nih.gov/articles/PMC8452362/
  28. https://www.unilever.com/our-company/our-history-and-archives/1800s/
  29. http://www.ers.usda.gov/amber-waves/2016/july/butter-and-margarine-availability-over-the-last-century
  30. https://www.soyinfocenter.com/HSS/hydrogenation1.php
  31. https://aocs.onlinelibrary.wiley.com/doi/10.1002/aocs.12614
  32. https://pubs.acs.org/doi/10.1021/ie50509a025
  33. https://www.alfalaval.ca/products/process-solutions/vegetable-oil-solutions/fat-modification-process-systems/
  34. https://pubs.acs.org/doi/10.1021/acsomega.0c02280
  35. https://www.evonik.com/en/products/ka/pr_52037202.html
  36. https://pubs.acs.org/doi/10.1021/acssuschemeng.0c06988
  37. https://www.newfoodmagazine.com/article/15680/partially-hydrogenated-oils-blessing-curse/
  38. https://talcottlab.tamu.edu/wp-content/uploads/sites/108/2019/03/Review-Lipid-Shortenings.pdf
  39. https://ecommons.cornell.edu/bitstreams/174026ee-729e-46d5-b08e-8d47b2bba76d/download
  40. https://www.sciencedirect.com/science/article/abs/pii/0021951774900852
  41. https://pmc.ncbi.nlm.nih.gov/articles/PMC7231579/
  42. https://www.sciencedirect.com/topics/food-science/trans-fatty-acid
  43. https://www.ahajournals.org/doi/10.1161/circulationaha.106.679985
  44. https://pubmed.ncbi.nlm.nih.gov/12716665/
  45. https://pubmed.ncbi.nlm.nih.gov/21753062/
  46. https://pubmed.ncbi.nlm.nih.gov/26268692/
  47. https://www.bmj.com/content/346/bmj.e8707
  48. https://www.bmj.com/content/353/bmj.i1246
  49. https://schaeffer.usc.edu/research/trans-fat-bans-linked-to-reduction-in-heart-attack-and-stroke/
  50. https://pubmed.ncbi.nlm.nih.gov/17268422/
  51. https://pubmed.ncbi.nlm.nih.gov/19424216/
  52. https://www.who.int/news-room/feature-stories/detail/denmark-trans-fat-ban-pioneer-lessons-for-other-countries
  53. https://pmc.ncbi.nlm.nih.gov/articles/PMC9385018/
  54. https://www.fda.gov/food/food-additives-petitions/trans-fat
  55. https://www.fda.gov/food/hfp-constituent-updates/fda-completes-final-administrative-actions-partially-hydrogenated-oils-foods
  56. https://www.mpoc.org.my/global-movement-against-trans-fat-the-growing-trend-of-restriction-and-reformulation/
  57. https://www.who.int/news/item/24-06-2024-WHO-5-year-milestone-report-on-global-transfat-elimination-illustrates-latest-progress-up-to-2023
  58. https://eur-lex.europa.eu/eli/reg/2019/649/oj/eng
  59. https://www.who.int/publications/i/item/9789240089549
  60. https://www.fda.gov/food/food-additives-petitions/final-determination-regarding-partially-hydrogenated-oils-removing-trans-fat
  61. https://www.food-safety.com/articles/5915-fdae28099s-pho-ban-and-the-path-towards-reformulation
  62. https://downloads.regulations.gov/FDA-2013-N-1317-0244/content.pdf
  63. https://www.fda.gov/media/170825/download
  64. https://resolvetosavelives.org/wp-content/uploads/2023/05/Trans-Fat-Elimination-Policy-in-Denmark-2.pdf
  65. https://pmc.ncbi.nlm.nih.gov/articles/PMC11640434/
  66. https://apps.fas.usda.gov/newgainapi/api/report/downloadreportbyfilename?filename=EU%2520Sets%2520Limit%2520for%2520Trans%2520Fats_Brussels%2520USEU_EU-28_5-8-2019.pdf
  67. https://www.fooddive.com/news/the-hidden-cost-of-non-pho-emulsifiers/401501/
  68. https://pmc.ncbi.nlm.nih.gov/articles/PMC5497165/
  69. https://www.sciencedirect.com/topics/nursing-and-health-professions/interesterification
  70. https://www.aocs.org/resource/chemical-interesterification/
  71. https://www.aocs.org/resource/enzymatic-interesterification/
  72. https://onlinelibrary.wiley.com/doi/10.1111/nbu.12397
  73. https://www.researchgate.net/publication/297967305_Interesterified_palm_products_as_alternatives_to_hydrogenation
  74. https://www.sciencedirect.com/science/article/abs/pii/S0023643820308690
  75. https://pmc.ncbi.nlm.nih.gov/articles/PMC4942855/
  76. https://ift.onlinelibrary.wiley.com/doi/10.1111/1541-4337.70088
  77. https://pmc.ncbi.nlm.nih.gov/articles/PMC10169972/
  78. https://www.sciencedirect.com/science/article/abs/pii/S0016236121014034
  79. https://www.researchgate.net/publication/273766104_Electrocatalytic_Hydrogenation_of_Vegetable_Oil
  80. https://www.sciencedirect.com/science/article/abs/pii/S0260877407003500
  81. https://pubs.rsc.org/en/content/articlelanding/2024/cy/d4cy00488d
  82. https://www.sciencedirect.com/science/article/abs/pii/S0896844608000806
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