Chemistry
Hydrogenated Fats
Hydrogenated fats are fats that have undergone the process of hydrogenation, which involves adding hydrogen to unsaturated fats to make them more saturated. This process results in the formation of trans fats, which are known to have negative health effects when consumed in excess. Hydrogenated fats are commonly found in processed and packaged foods.
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9 Key excerpts on "Hydrogenated Fats"
eBook - PDFFats and Oils
Formulating and Processing for Applications, Third Edition
- Richard D. O'Brien(Author)
- 2008(Publication Date)
- CRC Press(Publisher)
Chemically, fats and oils are a combination of glycerin and fatty acids called trig-lycerides . The portions of triglycerides that can be changed with hydrogenation are classified as unsaturated fatty acids. Saturated fatty acids contain only single carbon-to-carbon bonds and are the least reactive chemically. Physically, they have higher melting points and are solid at room temperature. Unsaturated fatty acids contain one or more carbon-to-carbon double bonds and are liquid at room temperature with sub-stantially lower melting points than their saturated fatty acid counterparts. In the pro-cess of hydrogenation, it is possible to chemically react hydrogen gas with the double bonds in the carbon chain of the unsaturated fatty acid, converting it to a more satu-rated fatty acid, shifting it to a new position, or twisting it to the trans configuration, all of which increase its melting point. Table 2.2 illustrates the chemical structure of the natural 18 carbon fatty acids and the changes possible with hydrogenation. Hydrogenation can take place only when the three reactants have been brought together: unsaturated oil, a catalyst, and hydrogen gas. The hydrogen gas must be dissolved in the liquid oil before it can diffuse through the liquid to the solid catalyst surface. Each absorbed unsaturated fatty acid can then react with a hydrogen atom to complete the saturation of the double bond, shift it to a new position, or twist it to a higher melting trans form. Both positional and geometric or trans -isomers are very important to the production of partially Hydrogenated Fats. If the unsaturated oil to hydrogenation contains mono-, di-, and triunsaturates, there may be competition for the catalyst surface. The di- and triunsaturates are preferentially absorbed and partially isomerized or hydrogenated to a monounsaturate until their concentration is very low, permitting the monounsaturate to be absorbed and reacted.
eBook - PDF- Khetarpaul, Neelam(Authors)
- 2021(Publication Date)
- Daya Publishing House(Publisher)
Meaning of Trans Fat A type of fat created when oils are hydrogenated, which chemically transforms them from their normal liquid state (at room temperature) into solids. During the hydrogenation procedure extra hydrogen atoms are pumped into unsaturated fat, thereby creating trans fatty acids. This process converts the mixture into a saturated fat, which obliterates its polyunsaturate benefits. Chemically speaking, trans fats are made of the same building blocks as non-trans fats, but are a slightly different shape. From a molecular perspective, the different shape is caused by double bonds between carbon atoms being in the trans rather than the cis configuration. Trans fats are more of a straight shape, while the cis shape is more kinked. This ebook is exclusively for this university only. Cannot be resold/distributed. Trans fatty acids can be found in a wide array of processed foods including cookies and margarines. Any food with “hydrogenated oils” or “partially hydrogenated oils” on the label contains trans fatty acids. Some researchers believe such foods may actually be more damaging than regular saturated fats to those watching their cholesterol, saying trans fatty acids decrease the good (HDL) cholesterol and increase the bad LDLs. Other scientists argue that the evidence is inconclusive and that trans fatty acids are no worse than butter. In either case, it would seem that “moderation” is the watchword when consuming foods containing trans fatty acids. At the turn of the century, a dramatic change in the fatty acid composition of the food supply of industrialized countries occurred when a process was discovered to convert liquid oils into solid or semisolid fats. In this process, known as partial hydrogenation, oils are heated in the presence of nickel or other metal catalysts and exposed to hydrogen gas.
eBook - ePub- G Talbot(Author)
- 2011(Publication Date)
- Woodhead Publishing(Publisher)
The term ‘structured triglycerides’ can mean many things. On the one hand it can mean the production of triglycerides of a specified fatty acid composition and structure; on the other it can mean the inclusion of a component within the fat phase that gives ‘structure’ to a more liquid, unsaturated oil. The former definition revolves around the ability of an oils and fats processor to produce specified compositions. To achieve this the industry has a number of process options to choose from and use.One of these, hydrogenation, has been the subject of much controversy over the past decade or so because if it is not allowed to go to completion it produces trans fatty acids. The response to this has differed from country to country. Denmark, for example, was the first country to limit the level of industrially produced trans fats (as opposed to ‘natural’ trans fats found in milk and meat of ruminant animals) to a maximum of 2% in oils and fats used in food. The United States, on the other hand, introduced mandatory labeling of the trans fatty acid content of foods as part of the nutritional declaration. The United Kingdom has done neither but, arguably, has not needed to do either because the response of the popular media in the United Kingdom, closely followed by the response of the major retailers, was to demonize the whole process of hydrogenation irrespective of whether it was partial hydrogenation producing trans fatty acids or complete hydrogenation producing only saturates and no trans fats. The result of this is that countries such as the United States can use triglycerides produced from complete hydrogenation (because there are then no longer any trans fatty acids present that need to be labelled) but it would be very difficult for such fats to be used in the United Kingdom, not because they are banned but because the use of ‘hydrogenation’ would need to be labelled. The UK consumer has been ‘trained’ to equate hydrogenation with trans even though that is not always the case.Fractionation is another process that can be used to obtain particular groups of triglycerides and is most commonly used with palm oil and palm kernel oil, although butter fractions and coconut oil fractions are also available commercially. Possibly the most useful method for producing triglycerides of a specific structure is enzyme-catalysed interesterification. This is particularly useful for producing triglycerides of the XYX structure in which fatty acids in the outside positions are of one type of group while the acid in the middle or 2-position of the triglyceride is of a different type or group.
eBook - PDFFrying of Food
Oxidation, Nutrient and Non-Nutrient Antioxidants, Biologically Active Compounds and High Temperatures, Second Edition
- Dimitrios Boskou, Ibrahim Elmadfa(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
These options include (1) modification of the hydrogenation process, (2) interesterification, (3) fractions from natural oils, high in solids, and (4) trait-enhanced oils. 10.3.2.1 Hydrogenation and Interesterification Processes Solid fats usually can be obtained in two different ways: partial hydrogenation leading to TFA-rich fats or full hydrogenation forming mainly SFA rich fats. Modifying the conditions of hydrogenation (e.g., pressure, temperature, and catalyst) affects the fatty acid composition of the resulting oil, including the amount of TFA formed, and properties such as melting point and solid fat con-tent. It is possible to make products of equivalent performance with low trans fats by increasing the degree of hydrogenation, which reduces the level of TFA but increases the level of saturated fatty acids (Table 10.2). Such fats will differ analytically from fats hydrogenated to a lesser degree because SFA will contrib-ute most to the solid content (Hunter, 2005). The interesterification process involves the rearrangement of the fatty acids in the glycerol backbone of the fat in the presence of a chemical catalyst, such as sodium methoxide, or an enzyme. Interesterification modifies the melting and crystallization behavior of the fat and the resulting fat is trans-free. Interesterified products include cocoa butter substitutes and lard. In chemical interesterification, a nonhydrogenated liquid plant oil with zero TFA and a fully hydrogenated vegetable oil (a hardstock) that has a low iodine value and TFA are mixed and heated. A typical blend may con-tain approximately 85% nonhydrogenated oil and approximately 15% hardstock. A newer method uses a specific lipase derived from microorganisms and immobilized on a granulated silica matrix. An interesterified fat has almost no TFA but higher levels of stearic, linoleic, and linolenic acids.
eBook - PDF- Dharma R. Kodali, Gary R. List(Authors)
- 2019(Publication Date)
- AOCS Publishing(Publisher)
The trans fat content of Hydrogenated Fats varies from 10% to as much as 40% based upon the extent of hydrogénation and hydrogénation conditions. This will be further discussed in the hydrogénation process described below. Minor amounts of trans fats also form under the deodorization conditions of vegetable oil processing. Another source of trans fats is of animal origin from dairy and meat products. The concentration of trans fats in dairy and meat fats is usually low, from 3-8%, and these trans fats are different from those formed by hydrogénation of vegetable oils. The bacteria present in the rumi-nants' gut hydrolyses the dietary fat and subjects the resulting fatty acids to biohy-drogenation. The initial step in this process involves the conversion of cis-2 double bond in polyunsaturated fatty acids to a trans-ll configuration, followed by the hydrogénation of a cis-9 double bond. Thus in biohydrogenation process linoleic acid gives rise to vaccinic acid, a trans-ll fatty acid. Because of this reason the trans fats of animal origin contain trans-ll vaccinic acid in greater concentration whereas the partially hydrogenated vegetable oils contain a higher concentration of trans-9 elaidic acid (Mossoba et al. 2003). The concentration of various trans isomers and their relative ratios can help to determine the origin of trans fats in the diet. For instance the examination of adipose fat can reveal the source of dietary trans fats, from either partially hydrogenated vegetable oil or ruminant fats (Combe 2003). 9 Trans Fats in Foods Trans Fats Reduction/Elimination Technologies In July 2003, FDA issued a final rule requiring a mandatory declaration in the nutri-tional label of the amount of trans fat present in foods including dietary supplements. The declaration of trans fat is to be expressed as grams per serving to the nearest 0.5 gram increment below 5 grams and to the nearest gram increment above 5 grams (Moss and Wilkening 2005).
eBook - PDF- Casimir C. Akoh(Author)
- 2005(Publication Date)
- CRC Press(Publisher)
In addition, trans fatty acids can be formed at very high temperatures (e.g., deodorization process and frying) and through hydrogenation reactions and biohydrogenation in ruminant animals. 10.3 HYDROGENATION Trans fatty acids are produced during hydrogenation of edible oils. The process of hydrogenation of edible oils is an important and widespread practice in the modifi-cation of oils, whereby all or part of the double bonds of the fatty acids are eliminated, thus producing a partially or completely hydrogenated fat, which possesses increased melting point, increased resistance to oxidation, and improved consistency [7–9]. By controlling the degree of hydrogenation, manufacturers can provide the consumer with fat products, such as margarines and shortenings, with the desired consistency and spreadability. The most prominent trans fatty acids formed from the partial hydrogenation of vegetable or fish oils are the ∆ 9 (elaidic) and ∆ 10 isomers [4,10]. 10.4 BIOHYDROGENATION In ruminant animals such as cows and sheep, unsaturated fatty acids are extensively hydrogenated in the rumen by bacteria [11–13]. Hay and Morrison [14] reported that complex enzyme systems of the rumen microflora are responsible for trans-forming the monounsaturated and polyunsaturated fatty acids in feedstuffs into saturated fatty acids and into geometric and positional isomers. The trans fatty acid produced by the rumen bacteria is predominantly vaccenic acid, which constitutes about 50% of all ruminant trans fatty acids [10,15]. As a result, dairy products and meats from ruminant animals contain small amounts of trans fatty acids [14,16–18]. 10.5 DIETARY SOURCES OF TRANS FATTY ACIDS The most important source of trans fatty acids in the food supply is from the commercial hydrogenation of edible oils and fats.
eBook - PDF- Alejandro G. Marangoni, Suresh S. Narine, Alejandro G. Marangoni, Suresh S. Narine(Authors)
- 2002(Publication Date)
- CRC Press(Publisher)
Another challenging problem is the control of crystallization conditions so as to minimize the amount of solid fat required to create a fat crystal network in shortenings used in the manufacture of bakery products. In some food manufacturing processes, it is necessary that the fat crystallization process be complete by the end of the Copyright 2002 by Marcel Dekker. All Rights Reserved. production line. In this case, it is necessary to understand the crystallization be-havior of the particular fat(s) used and the effects that processing as well as chemical and physical modification such as hydrogenation, interesterification, and fractionation may have. The aim of this study is to investigate the nucleation and isothermal crystal-lization behavior of sunflower seed oil hydrogenated under selective and nonse-lective conditions. Two methods were used to measure induction times of crystal-lization and compared. Measurements of solid fat content by nuclear magnetic resonance (NMR) and a description of the growth behavior in terms of number and size of the crystals formed are also reported. II. HYDROGENATION PROCESS Hydrogenation and interesterification are two important industrial processes used to give fats and oils a desired functionality for specific products. Currently, for-mulators can raise the melting point and solid fat content of fats by (1) hydro-genating oils to different degrees of hardness or (2) interesterifying a liquid oil with a more saturated oil [1]. The aim of the hydrogenation process is to fully or partially saturate the double bonds in unsaturated fats and oils in order to obtain plastic fats and/or improve oxidative stability. The final product depends on the nature of the starting oil, the type and concentration of the catalyst used, the concentration of hydrogen, and the experimental conditions under which the reaction takes place [2].
- Ching Kuang Chow(Author)
- 2007(Publication Date)
- CRC Press(Publisher)
782 D. Use of Trait-Enhanced Oils ......................................................................................... 783 VII. Current Status of Usage of Zero- and Low-Trans Fats ..................................................... 784 VIII. Summary and Conclusions ............................................................................................... 784 Acknowledgments ....................................................................................................................... 785 References ................................................................................................................................... 785 Safety and Health Effects of Trans Fatty Acids J. Edward Hunter 31 758 Fatty Acids in Foods and Their Health Implications Administration (FDA) issued regulations requiring the labeling of trans fatty acids on packaged foods effective from January 1, 2006. In addition, many food manufacturers, who have used par-tially hydrogenated oils in their products, have developed or are considering ways to reduce or eliminate trans fatty acids from these products. This chapter updates that of Hunter (2000) and covers the following topics: (1) occurrence of trans fatty acids in the U.S. food supply; (2) review of human studies relating dietary trans fatty acids to risk of coronary heart disease (CHD); (3) review of studies relating dietary trans fatty acids to other health conditions, such as cancer, maternal and child health, type 2 diabetes, and macular degeneration; (4) dietary recommendations regarding trans and saturated fatty acids by health pro-fessional organizations; and (5) alternatives for replacing or reducing trans fatty acids in foods. II. OCCURRENCE OF TRANS FATTY ACIDS IN THE U.S. FOOD SUPPLY Unsaturated fatty acids in foods can exist in either the cis or trans conguration (Figure 31.1). In the cis form, the hydrogen atoms are on the same side of the double bond.
eBook - PDFSoybean
Bio-Active Compounds
- Hany A. El-Shemy(Author)
- 2013(Publication Date)
- IntechOpen(Publisher)
Chapter 15 The Effects of Hydrogenation on Soybean Oil Fred A. Kummerow Additional information is available at the end of the chapter http://dx.doi.org/10.5772/52610 1. Introduction Soybeans are very versatile, both as a food product and an ingredient in many industrial products. The oil produced by soybeans is contained within many foods we eat every day. Natural soybean oil contains several essential fatty acids that our body needs to work prop‐ erly, including linoleic and linolenic acids. However, much of the soybean oil consumed in many parts of the world has been partially hydrogenated; that is, it's chemical composition has been changed. This hydrogenation removes the necessary essential fatty acids contained within the original oil. Some of the partially hydrogenated soybean oil has been converted to trans fatty acids. Trans fatty acids have been shown to increase the risk of atherosclerosis and coronary heart disease due to their in vivo effects in two ways. They effect the levels of prostacyclin and thromboxane, which increases the risk of thrombosis, and they increase sphingomyelin pro‐ duction by the body, which then causes calcium influx into the arterial cells to increase, leading to atherosclerosis. Consumption of partially hydrogenated soybean oil can be harm‐ ful to the body. 2. Soybeans Soybeans have many uses. When processed, a 60-pound bushel will yield around 11 pounds of crude soybean oil and 47 pounds of meal. Soybeans are about 18% oil and 38% protein. Because soybeans are high in protein, they are a major ingredient in livestock feed. Most soybeans are processed for their oil and protein for the animal feed industry. A smaller per‐ centage is processed for human consumption and made into products including soy milk, soy protein, tofu and many retail food products. Soybeans are also used in many non-food (industrial) products [1].
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