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- Sprache: Englisch
OILS AND FATS AS RAW MATERIALS FOR INDUSTRY This new volume emphasizes the sources, structure, chemistry, treatment, modification, and potential applications for oils and fats as raw materials in industry. Oils and fats can be used as raw materials in many industries including food and agriculture, as surfactants in laundry detergents and cosmetics, as well as in pharmaceuticals. Moreover, unsaturated vegetable oils are also suitable to form epoxides and hence, are important in the manufacturing of paints and adhesives. Limited sources of petrochemicals and their harmful effects on health and the environment also promote the use of naturally occurring oils and fats as biodiesel after some chemical modification. Moreover, a vast variety of nonedible oils that can be obtained from easily cultivable plant species are receiving great interest from researchers because they not only yield cost-effective products but are also proven as a substrate to promote sustainable research. In this book, the editors will cover all possible industrial applications of the products that are formed using edible and non-edible vegetable oils. Vegetable oils are not a new research area, although they are considered an evergreen or long-lasting topic as most of the research in synthetic chemistry has been carried out on vegetable oils.
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Table of Contents
Cover
Table of Contents
Series Page
Title Page
Copyright Page
Preface
1 Oil and Fats as Raw Materials for Industry: An Introduction
1.1 Introduction
1.2 Classification of Oils and Fats
1.3 Chronology of the Development of Oil and Fats for Industry
1.4 Chemistry of Oil and Fats
1.5 Properties of Oils and Fats
1.6 Applications of Oils and Fats
1.7 Challenges
1.8 Conclusion
References
2 Biotechnology for Oil and Fat
2.1 Introduction
2.2 Review of Literature
2.3 Conclusion
Acknowledgement
References
3 Sustainability of Oils and Fats Over Petrochemicals
3.1 Oils and Fats as Renewable Feedstock
3.2 Petrochemicals as Non-Renewable Feedstock
3.3 Oils and Fats vs. Petrochemicals
3.4 Trends in the Oleochemical Industry
3.5 Oleochemicals & Petrochemicals Surfactants
3.6 Oleochemicals-Based Products
3.7 Conclusion
References
4 Oils and Fats in the Food Industry
4.1 Introduction
4.2 Sources of Oils and Fats
4.3 Methods of Extraction
4.4 Constituents of Fat and Oil
4.5 Physical Properties
4.6 Chemical Characteristics
4.7 Nutritional Properties
4.8 Applications
References
5 Oils and Fats as an Environmentally Benign Raw Material for Surfactants and Laundry Detergents
5.1 Introduction
5.2 History of Laundry Detergent
5.3 Raw Materials in Laundry and Detergents
5.4 Types of Surfactants
5.5 Synthesis Methods
5.6 Market Analysis
5.7 Environmental Safety
5.8 Future Trends
5.9 Conclusion
References
6 Oils and Fats as Raw Materials for Cosmetics
6.1 Introduction
6.2 Theoretical Aspects of Emollients
6.3 Commonly Used Vegetable/Plant Derived Oils
6.4 Lanolin and Its Derivatives
6.5 Lecithin
6.6 Essential Oils
6.7 Use of Waxes in Cosmetics
6.8 Use of Oils, Fats and Waxes in Lipsticks and Eye Care Products
6.9 Cleansing Creams
6.10 Oil Shampoo
6.11 Conclusion
References
7 Oil and Fats as Raw Materials for Coating Industries
7.1 Introduction
7.2 Vegetable Origin Oils and Fats
7.3 Animal Origin Fats & Oils
7.4 Various Applications of Oils and Fats in Coating Industry
7.5 Regulatory and Safety Issues of Vegetable Oil and Fats Coatings
7.6 Patents of Oils and Fats Used for Industrial Coating
7.7 Recent Approaches for Coating
7.8 Conclusions
References
8 Oil and Fats as Raw Materials as Corrosion Inhibitors and Biolubricants
8.1 Introduction
8.2 Biolubricants from Vegetable Oil
8.3 Renewable Feedstocks Available in India
8.4 Ester-Based Lubricants from Vegetable Origin Oils (Edible and Non-Edible Oil)
8.5 Epoxide-Based Lubricants from Vegetable Oil
8.6 Conclusion
References
9 Vegetable Oils in Pharmaceutical Industry
9.1 Introduction
9.2 Olive Oil
9.3 Rice Bran Oil
9.4 Soybean Oil
9.5 Walnut Oil
9.6 Sesame Oil
9.7 Peanut Oil
9.8 Sunflower Oil
9.9 Conclusions
References
10 Non-Edible Oils as Biodiesel
10.1 Introduction
10.2 Tussle Between Food and Fuel
10.3 Non-Edible Oils as Potential Feedstock
10.4 Non-Edible Plants as Raw Material
10.5 Properties of Non-Edible Oils for Biodiesel as a Future Fuel
10.6 Extraction of Non-Edible Oil
10.7 Emissions Characteristics of Non-Edible Vegetable Oils
10.8 Conclusion
References
11 Ecological and Economic Aspects of Oil and Fats
11.1 Introduction
11.2 Disparities in Price
11.3 Environmental Effects of Oils
11.4 Global Trends
References
12 Oils and Fats: Raw Materials for Corrosion Inhibitor
12.1 Introduction
12.2 Essential Oil as Corrosion Inhibitor
12.3 Fatty Acids as Corrosion Inhibitors
12.4 Copper Corrosion Inhibitor by Fatty Amidine
12.5 Palm Oil as Corrosion Inhibitor
12.6 Flower Extracts as Corrosion Inhibitor
12.7 Fatty Amide Derivatives Used as Corrosion Inhibition of Carbon Steel
12.8 Unsaturated Fatty Acid Derived by Microalgae as Corrosion Inhibitor
12.9 Other Green Inhibitors
12.10 Conclusions
References
Index
Also of Interest
End User License Agreement
List of Tables
Chapter 2
Table 2.1 List of food items enriched with different types of fatty acid.
Table 2.2 Distribution of fatty acid content in different types of living orga...
Table 2.3 Fatty acid profile of selected conventional oilseeds (a) Saturated f...
Table 2.4 Fatty acid profile in selected seed of unconventional plant.
Chapter 4
Table 4.1 Applications of edible oils from various sources.
Chapter 7
Table 7.1. Oils and fats obtained from plant source.
Table 7.2. Various type of animal-derived fats and oils.
Chapter 8
Table 8.1. Correlation characteristics of Gas, SCF and liquid.
Table 8.2. Non-edible oilseed plants in India.
Chapter 10
Table 10.1 Biodiesel consumption of five countries.
Table 10.2 Potential feedstock for the production of biodiesel.
Table 10.3 Production of non-edible crops annually.
Table 10.4 Composition of fatty acids present in non-edible oil for the produc...
Table 10.5 Properties of biodiesel.
Chapter 11
Table 11.1 Comparing the psychochemical properties of palm biodiesel with mine...
Chapter 12
Table 12.1 Typical fatty acid composition (%) of palm oil.
List of Illustrations
Chapter 1
Figure 1.1 Classification of fats and oils.
Figure 1.2 Structure of Octadecanoic acid.
Figure 1.3 Structure of Hexadecanoic acid.
Figure 1.4 Structure of Tetradecanoic acid.
Figure 1.5 Structure of Dodecanoic acid.
Figure 1.6 Structure of Decanoic acid.
Figure 1.7 Structure of Octanoic acid.
Figure 1.8 Structure of Butanoic acid.
Figure 1.9 Structure of Propanoic acid.
Figure 1.10 Structure of Ethanoic acid.
Figure 1.11 Schematic representation of triacylglycerol structure having three...
Figure 1.12 Structure of Butane-2,3-dione and 3-hydroxy-2-butanone.
Figure 1.13 Process of Saponification.
Chapter 2
Figure 2.1 Biological application of fatty acids in different industrial secto...
Figure 2.2 Chemical process for synthesis of triglyceride from glycerol and fa...
Figure 2.3 Structure of different configuration of unsaturated fatty acid.
Figure 2.4 Structure configuration for mono and polyunsaturated fatty acid.
Chapter 3
Figure 3.1 Applications of oleochemicals.
Figure 3.2 Classification of petrochemicals.
Figure 3.3 Applications of petrochemicals.
Figure 3.4 Trends in the oleochemicals industry.
Figure 3.5 Oleochemicals & petrochemicals surfactants.
Chapter 4
Figure 4.1 Unit operations involved in extraction and processing of edible oil...
Chapter 5
Figure 5.1 Structure of paraffin sulfonates.
Figure 5.2 Structures of non-ionic surfactants.
Figure 5.3 Structures of Zwitterionic surfactants.
Figure 5.4 Synthesis of different functionalities of oils and fats.
Figure 5.5 Synthesis of amino acid-based surfactants from Jatropha oil.
Figure 5.6 Synthesis of sulphated ethanolamide based surfactants from vegetabl...
Figure 5.7 Synthesis of sugar-based surfactants from vegetable oils.
Figure 5.8 Trend of product type of laundry detergents.
Chapter 7
Figure 7.1 Vegetable origin oils and fat.
Figure 7.2 Types of animal origin fats and oils.
Figure 7.3 Chemical modification of vegetable oil as coating material [68].
Chapter 8
Figure 8.1 Global consumption of lubricants.
Figure 8.2 Lubricant consumption across different sectors in India.
Figure 8.3 Phase (pressure-temperature) diagram for CO
2
: CP=critical point, TP...
Figure 8.4 Variation of viscosity and density of CO
2
versus pressure at temper...
Figure 8.5 Transesterification of TAG to produce esters and glycerol.
Chapter 11
Figure 11.1 The percentage contribution of various crops to global vegetable o...
Figure 11.2 Global utilization of oils and fats.
Guide
Cover Page
Table of Contents
Series Page
Title Page
Copyright Page
Preface
Begin Reading
Index
Also of Interest
WILEY END USER LICENSE AGREEMENT
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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Oils and Fats as Raw Materials for Industry
Edited by
Divya Bajpai Tripathy
Anjali Gupta
Pooja Agarwal
Anuradha Mishra
and
Arvind Kumar Jain
This edition first published 2024 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA© 2024 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.
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Library of Congress Cataloging-in-Publication Data
ISBN 9781119910411
Cover image: Pixabay.comCover design by Russell Richardson
Preface
In today’s world, oils and fats play a crucial role in various industries and applications. From the food industry to cosmetics, from pharmaceuticals to coating industries, these versatile substances have become indispensable raw materials. With increasing concerns about sustainability and environmental impact, there is a growing need to explore alternative sources and utilize biotechnology to harness the potential of oils and fats. This book is divided into 12 chapters, discussing the potential of oil and fats as raw materials for various industrial sectors.
In chapter 1, fundamentals of oils and fats has been covered. Discussion has been made on their various types, ranging from vegetable oils to animal fats, on their chemistry and properties. Understanding the characteristics of different oils and fats is essential to comprehend their applications across industries.
The second chapter of the book is focuses on the advancements in biotechnology that have revolutionized the production and utilization of oils and fats. We explore the role of biotechnology in enhancing yield, improving quality, and developing sustainable processes. The chapter highlights the potential of genetic engineering, enzyme technology, and other biotechnological tools in the field of oils and fats.
Chapter 3 of the book is based on the sustainability of oils and fats over petrochemicals. This chapter insights the concerns about the environmental impact of petrochemicals rise and examines the sustainability of oils and fats as an alternative. Comparison on the ecological footprint of oils and fats with that of petrochemicals and discuss the advantages and challenges associated with transitioning to renewable sources has been done. The chapter also addresses the importance of sustainable sourcing and production practices.
The fourth chapter explores the extensive use of oils and fats in the food industry. This discusses their role in cooking, flavouring, and texture enhancement, and their impact on product quality. Additionally, the chapter examines the health considerations associated with consuming different types of oils and fats, shedding light on the ongoing debates surrounding their effects on human health.
Chapter 5 investigates the potential of oils and fats as raw materials for surfactants and laundry detergents. Traditional petrochemical-based surfactants can have adverse environmental effects, and this chapter explores the benefits of utilizing renewable sources to produce eco-friendly alternatives. Challenges and opportunities in this emerging field has also been covered.
Cosmetics have long relied on oils and fats for their moisturizing, emollient, and functional properties. Chapter 6 examines the use of oils and fats in the cosmetic industry, ranging from skincare to haircare products and delve into the formulation aspects and discuss the growing demand for natural and sustainable ingredients.
Coatings are essential for protection and enhancement in numerous industries. In seventh chapter, applications of oils and fats as raw materials for coatings has been explored. In addition, their role in providing durability, adhesion, and corrosion resistance, while also considering the sustainability aspects of such coatings have also been discussed.
The eighth chapter focuses on the utilization of oils and fats as raw materials for corrosion inhibitors and biolubricants. We delve into their effectiveness in protecting metal surfaces from degradation and their potential as environmentally friendly lubricants. The chapter discusses the challenges in implementing these alternatives and their benefits for various industries.
The pharmaceutical industry constantly seeks new and innovative solutions, and vegetable oils have emerged as promising candidates. This chapter delves into the unique properties of vegetable oils and their applications in pharmaceutical formulations. From drug delivery systems to excipients, vegetable oils offer numerous advantages, such as improved bioavailability and enhanced stability. We explore the latest research and developments in this exciting field.
As the world strives towards a greener future, the search for sustainable energy sources becomes increasingly crucial. In this chapter, we explore the utilization of non-edible oils as biodiesel. These oils, derived from plants that are not traditionally used for food, offer a renewable and environmentally friendly alternative to conventional fossil fuels. Chapter 10 delves into the production methods, properties, and challenges associated with non-edible oils as biodiesel, shedding light on their potential impact on energy sustainability.
Oils and fats play a significant role in both ecological and economic realms. Chapter 11 examines the intricate relationship between oil and fat production, consumption, and their environmental impact and explores the topics such as deforestation, land use, and the carbon footprint associated with oil production, as well as the economic implications of oil markets and trade. By understanding the ecological and economic aspects of oils and fats, decisions to foster a sustainable and balanced future can be made.
Corrosion poses a significant challenge across various industries, leading to economic losses and safety concerns. In chapter 12, potential of oils and fats as raw materials for corrosion inhibitors has been explored. This last chapter of the book delve into the unique properties of these substances that make them effective in preventing or reducing corrosion. By examining their mechanisms of action and applications, the possibilities of harnessing oils and fats to mitigate the damaging effects of corrosion have been uncovered.
Throughout this book, editors and authors aim to provide a comprehensive understanding of oils and fats, showcasing their versatility and potential in different fields. From pharmaceutical applications to energy sustainability and environmental considerations, the chapters ahead will shed light on the multifaceted nature of oils and fats. This exploration will inspire further research and innovation, pushing the boundaries of what oils and fats can achieve.
Divya Bajpai Tripathy
Anjali Gupta
1Oil and Fats as Raw Materials for Industry: An Introduction
Sonali Kesarwani1, Mukul Kumar1, Divya Bajpai Tripathy2*, Anjali Gupta2 and Suneet Kumar3
1Division of Forensic Science, School of Basic and Applied Sciences, Galgotias University, Greater Noida, Uttar Pradesh, India
2Division of Chemistry, School of Basic and Applied Sciences, Galgotias University, Greater Noida, Uttar Pradesh, India
3Forensic Science Laboratory, Moradabad, Uttar Pradesh, India
Abstract
Worldwide, fats and oils occupy major roles in nearly all industries like food, pharmaceutical, surfactants, biodiesel, agriculture, etc. The major renewable raw materials for the chemical industry are oils and fats, which are lipids. When ingested in sufficient quantities, they serve as a vital component of a healthy diet. Triacylglycerols (TAGs), also referred to as triglycerides, are essentially ester-linked glycerol moieties connected with three fatty acids that make up oils and fats. These fatty acids provide fats with useful properties. Because of the modification in lipids with improved nutritional and functional qualities, scientists and researchers have recently developed a growing interest in fats and oils. Triacylglycerols have a variety of properties and use depending on their structure and lipid composition. Therefore, altering the TAGs of lipids is a method for producing personalized lipids and expanding the range of their applications. Due to the detrimental health effects of trans fats, which are mostly brought on through partial hydrogenation, interesterification has become the dominant alternative strategy. This chapter provides a wide range of unprocessed fats and oils, along with information on their characteristics, classification, and historical evolution. In addition, the chapter emphasises the applications and difficulties in this field.
Keywords: Fats, oils, raw materials, saturated, unsaturated, applications, triglycerides
1.1 Introduction
“Fatty acids” (FAs) are molecules with long carbon chains in which the hydrogen atoms are connected to carbon atom bonds along with chains bearing carboxyl (-CO) as a functional group. Fatty acids are the building blocks of “fats” and “oils. “Saturated” fats are simple straight chains of carbon (C) atoms having alkanes, i.e., only single bonds between C-atoms, whereas unsaturated fats have alkenes or alkynes, i.e., double or more bonds. As a result, polyunsaturated fatty acids have more than two double bonds between C-atoms while monounsaturated fatty acids only have one double bond [1].
Natural fats and oils are mainly composed of triacylglycerols (TAGs), and the composition and molecular structure of TAGs differ from the physico-chemical and determines functional and nutritional properties of fatty acids, i.e., saturated, mono or polyunsaturated [2]. The suitability of fats and oils are usually determined by their physico-chemical properties. The use of the words “oil and fat” in most languages recognizes the property of being liquid or solid at ambient temperature as the basis for distinguishing between these two classes of products [3]. The molecular structure, melting and crystallization behaviour, and rheological properties of fats and oils are important for the rational design of lipid materials [4]. It is well known that the properties of fats and oils mainly depend on their triacylglycerol composition, i.e., the unsaturation degree and carbon chain length of the TAGs component fatty acid (FA) molecules [5].
Oils and fats are organic compounds with carboxylic acids as active elements. As a renewable source, oils and fats from plant seeds and animal tissues are used to manufacture petroleum products in industries [6]. Fats and oils are a “great source of energy (9 kcal/g) and essential fatty acids such as linoleic acid (18:2), linolenic acid (18:3), EPA (20:5) and DHA (22:6) to humans” [7]. Fats have a vital role in meat products, influencing organoleptic like palatability, texture and flavour, and technological aspects like cooking loss, emulsion stability, water holding capacity and rheological properties. In comparison to animal fats, vegetable oils have a higher ratio of unsaturated to saturated fatty acids and do not include cholesterol [8]. Being a source of important fatty acids and fat-soluble bioactive substances, vegetable oils and fats are a crucial part of the human diet.
Palm oil, sunflower oil, rapeseed oil and soybean oil are the four edible vegetable oils that are traded the most on a global scale. Interest in alternate sources of vegetable oils has developed due to the current demand for oils and fats for human consumption, with an emphasis on nutritious eating and new industrial uses [9]. Studies on the chemical and physical characteristics of oils and fats produced from distinctive oil plants have been done in order to identify substitute lipid sources with high nutritional value as well as to enhance commercial applications [10]. Due to the presence of carotenoids and chlorophyll pigments, vegetable oils are often clear and have a yellow or green colour [7]. Dietary sources of fats that play significant and varied roles in biological processes include vegetable oils and animal fats. Triacylglycerols are important components of oils and fats, and the profiles of various oils and fats varies significantly. For nutritional evaluation, quality assurance, and ensuring the safety of oils and fats, TAG profiles are required [11].
According to O’Brien (2009), “edible oils and fats consisting of esters of glycerine and fatty acids (>90%) are structurally distinguished from triglycerol based on their chain length, the position of the double and cis/ trans bonds as well as the relative ratios of saturated and unsaturated fatty acids, i.e., number and position of double bonds” [9]. In human nutrition, meats, fats, edible oils, fish, dairy products and nuts are the main sources of lipids in the human diet. Researchers have found that “dietary fatty acids play an important role in cholesterol metabolism and thus may be associated with cardio-vascular disease (CVD)” [12]. As we gain more knowledge about the relation between dietary fats and fatty acids and chronic diseases, particularly coronary artery disease (CAD), the significance of edible fats and oils in health and illness continues to develop [13].
In total, India grows nine different oil seed crops, seven of which are used to make edible oils, including sunflower, safflower, oilseed rape (mustard), niger, sesame, soybean, and peanut. Linseed and Castor, on the other hand, are non-edible oil seeds. Significant amounts of edible oil are also produced by maize germ, cotton seed, and rice bran [13]. Fats and oils are widely used in domestic and industrial settings, as well as being the most frequent contaminants in wastewater. Because they are typically removed by physical processes in sewage treatment plants, these substances are left behind in large quantities that are challenging to discard and process [13]. Fats and oils are significant organic components of municipal and industrial wastewaters, although it is unclear how they behave exactly during the treatment process [14]. Although recent advances in this sector have made it possible to remove a sizable part of oil from wastewater, biological treatment of oily wastewater is not well developed [15]. Anaerobic digesters of various designs have been researched for the treatment of sludge and oil simultaneously. For instance, anaerobic co-digestion of food waste, oils and fats with sewage sludge [16], long-chain fatty acids of oils and fats with municipal sludge [17], and aerobic co-digestion of sludge with oils and fats were also examined [18, 19].
1.2 Classification of Oils and Fats
Essential nutrients in a good diet include oils and fats. The terms oil and fat differ by the states of triglycerides, i.e., at room temperature, liquid triglyceride is termed as oils whereas at solid state it is fat [20]. Most commonly used oils and fats have long chain fatty acids, i.e., typically 8 to 20 carbon atoms, mostly having an even number of carbons; however, an odd number of carbon long chains is found mostly in animal fats. Such fatty acids contain -CH3 (methyl) group at one end and -COOH (carboxylic acid) group at other end. An ester bond of triacylglycerol is formed by the reaction of this carboxylic group with the hydroxyl (-OH) group present on the glycerol molecule [20].
Figure 1.1 Classification of fats and oils.
The three main groups of fatty acids (Figure 1.1) can be divided according to chain length:
Long-chain fatty acid
Medium-chain fatty acid
Short-chain fatty acid
1.2.1 Long-Chain Fatty Acid
Long-chain fatty acids (LCFAs) comprise 13 to 21 carbon atoms having an aliphatic end, as a result of hydrolysis of neutral triglycerides. Palmitate, stearate, and oleate are the three most abundant LCFAs present in the system where digestion takes place in the absence of oxygen termed as anaerobic digesters [21].
1.2.1.1 Long-Chain Saturated Fatty Acid
Saturated fats are solid at room temperature, which is why they are also called solid fat. It is primarily present in “foods of animal origin, like milk, cheese, and meat. Poultry and fish contain less saturated fat than red meat [22]. Saturated fats are also found in tropical oils, such as coconut oil, palm oil, and cocoa butter. Tropical oils like saturated fatty acids are also found in many snacks and non-dairy foods, such as coffee creamer and whipped toppings. Foods made with butter, shortening (pastries and cakes, cookies, and other similar desserts) or margarine, have higher saturated fats which can elevate cholesterol levels. A healthy diet contains less than 10% of daily calories from saturated fat” [22].
Below are the most common long-chain saturated fatty acids.
1.2.1.1.1 Stearic Acid (18 Carbon Atoms)
Stearic acid is a long-chain saturated fatty acid with an 18-C framework and molecular formula C18H36O2 (Octadecanoic acid), Figure 1.2[23]. It is waxy-solid in texture. Stearic acid is present in “fats and oils of various plants and animals and is one of the useful types of saturated fatty acids, and a major constituent of cocoa butter and shea butter” [23].
Figure 1.2 Structure of Octadecanoic acid.
1.2.1.1.2 Palmitic Acids (16 Carbon Atoms)
Palmitic acid is a long-chain saturated fatty acid with a 16-C framework and molecular formula C16H32O2 (Hexadecanoic acid), Figure 1.3. Palmitic acid is naturally present in “palm oil and palm kernel oil, milk, butter, cheese, and meat” [24].
1.2.1.1.3 Myristic Acid (14 Carbon Atoms)
The saturated long-chain fatty acid having 14-C framework forms a myristic acid with molecular formula C14H28O2 (Tetradecanoic acid), Figure 1.4. The sources of myristic acid are palm oil, coconut oil, and butter fat [25, 26].
1.2.1.2 Unsaturated Fatty Acid
At normal temperature, fats and unsaturated fatty acids are liquid. This type of fatty acid is generally present in oils from plants and helps to improve cholesterol levels [27]. Unsaturated fats are further classified as Monounsaturated fat and Polyunsaturated fat.
1.2.1.2.1 Monounsaturated Fat
The sources of monounsaturated fats are “avocados, nuts, and vegetable oils, like olive, peanut oil, and canola. Eating foods that are high in such fat can help lower your ‘bad’ low density lipoprotein (LDL) cholesterol. Thus fat can also maintain ‘good’ high density lipoprotein (HDL) cholesterol levels high. However, by only consuming higher unsaturated fat without reducing saturated fat may not lower your cholesterol” [27].
Figure 1.3 Structure of Hexadecanoic acid.
Figure 1.4 Structure of Tetradecanoic acid.
Example: Omega-9 (or n-9) fatty acids, that contain first double bond at 9th C-atom and include mainly oleic acid [27].
1.2.1.2.2 Polyunsaturated Fat
Polyunsaturated fat is mainly stored in “vegetable oils such as safflower, corn oils, soybean, sesame and sunflower. It is also the main fat present in seafood” [28]. Low-density lipoprotein cholesterol may be decreased by polyunsaturated fats rather than saturated fats. Omega-6, omega-9, and omega-3 fatty acids are three common polyunsaturated fats [27, 28].
Examples:
Omega-3 fatty acids are found in “foods from plants like soybean oil, canola oil, walnuts, and flaxseed. They are also found in fatty fish and shellfish as Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA)” [22, 27, 29].
Omega-6 fatty acids are found mainly in “liquid vegetable oils like corn oil, safflower oil, and soybean oil” [27].
An unsaturated fatty acid is further categorized in two forms, i.e., bent form “cis” and straight form “trans”, based on the position of H-bond, i.e., whether it is on the same, or the opposite side of the molecule. Mostly unsaturated fatty acids are in the cis form [30].
1.2.1.3 Cis-Unsaturated Fatty Acid
Cis-unsaturated fatty acids are fatty acids having carboxylic acids attached with long aliphatic carbon chains, being two H-atoms linked by double bond on the same side of C-chain. This type of configuration is known as “cis configuration of unsaturated fatty acids” [31, 32].
Sources of cis-unsaturated fatty acids include “palm oil, nuts and seeds, avocados, and animal fats. Some vegetable oils, such as olive oil (75%), mid-oleic sunflower oil (70%), and rapeseed oil (65%), contain more than 50% of cis-MUFA” [30–32].
1.2.1.4 Trans-Unsaturated Fatty Acid
This fat has undergone a procedure known as hydrogenation. This method makes fat tougher at room temperature and extends the shelf life of the fat. Crispier crackers and flakier pie crusts are produced by harder fat [31]. Consuming more trans-fat increases the cholesterol level, hence it is advisable to consume a lesser amount of it.
Processed foods, “foods prepared with butter, some margarine, and partially hydrogenated oils, snacks including chips and crackers, cookies, certain margarine, and salad dressings are all sources of trans fatty acids” [32].
There are two categories of trans fatty acids (TFA): naturally occurring TFA (ruminant) and industrially produced artificial TFA.
Artificial trans-fats: During the hydrogenation of vegetable oils, which produces partially hydrogenated vegetable oils, artificially or industrially generated trans-fats (iTFAs) are produced. Epidemiologic and biochemical evidence is mounting that iTFAs negatively impact a number of cardio-vascular risk factors, raising the cases of coronary heart disease (CHD) globally [33].
Natural trans fats (ruminant): However, ruminant TFA is formed naturally by the enzymes of microorganisms found in the rumen of animals. This process, known as biohydrogenation, is a complicated one that results in the isomerization, hydration, or hydrogenation of dietary fatty acids that have not been esterified. After being formed, ruminant TFA is ingested and integrated into lipids found in milk and bodily tissue [34–36].
1.2.2 Medium-Chain Fatty Acid
Milk fat and coconut oil both naturally contain medium-chain fatty acids (MCFA). Coconut oil is used to make medium-chain triglycerides (MCT). In comparison to triglycerides containing fatty acids with 16 or 18 C atoms, short- or medium-chain fatty acid triglycerides have a higher fraction of carbon and hydrogen in the molecule and a lower energy density [37]. Here are a few illustrations of medium-chain fatty acids:
1.2.2.1 Lauric Acid (12 Carbon Atoms)
The medium chain saturated fatty acid having 12-C framework and molecular formula C12H24O2 (Dodecanoic Acid), Figure 1.5 is termed as Lauric acid. “It is found naturally in various plant and animal fats and oils and is a major component of coconut oil and palm kernel oil [38]. It is an inexpensive, non-toxic and safe-to-handle compound often used in laboratory investigations of melting-point depression. It is a solid at room temperature but melts easily in boiling water, so liquid lauric acid can be treated with various solutes and used to determine their molecular masses” [38].
Figure 1.5 Structure of Dodecanoic acid.
1.2.2.2 Capric Acid (10 Carbon Atoms)
Medium-chain straight saturated fatty acid having 10-C framework and molecular formula C10H20O2 (Decanoic acid), as seen in Figure 1.6, is termed as capric acid. It has a melting point of 31.5 °C and is a white, crystalline solid with a sour smell [40].
1.2.2.3 Caprylic Acid (8 Carbon Atoms)
Medium-chain saturated fatty acid having 8-C backbone and the chemical formula C8H16O2 (Octanoic acid), as seen in Figure 1.7, forms caprylic acid. “Numerous mammals’ milk naturally contains octanoic acid, which is also a minor component of coconut oil and palm kernel oil” [39].
1.2.3 Short-Chain Fatty Acids
Saturated fatty acids that comprise less than 6-C atoms are known as “short-chain fatty acids (SCFAs). The primary metabolic by-products of anaerobic bacterial fermentation in the intestine are short-chain fatty acids. SCFAs influence various processes in the gastrointestinal (GI) tract as well as in other tissues like adipose and immunological tissues, in addition to playing a crucial role as fuel for intestinal epithelial cells” [41].
Here are some of the most significant SCFAs:
Figure 1.6 Structure of Decanoic acid.
Figure 1.7 Structure of Octanoic acid.
1.2.3.1 Butyric Acid (4 Carbon Atoms)
A short-chain fatty acid having 4-C framework and molecular formula C4H8O2(Butanoic acid) as seen in Figure 1.8, forms butyric acid. It appears as a colourless liquid with a strong, unpleasant odour. It causes corrosion to metals and tissues. It has a 70 °F flash point and 8.0 lbs/gallon density [42].
1.2.3.2 Propionic Acid (3 Carbon Atoms)
Propionic acid, with the chemical formula C3H6O2 (Propanoic acid), is a short-chain saturated fatty acid that has ethane linked to the carbon of a carboxy group (Figure 1.9). It is a colourless liquid that emits an irritating vapour and has a strong rancid odour. It functions as an antifungal medication. It is the propionate conjugate acid [43].
1.2.3.3 Acetic Acid (2 Carbon Atoms)
Acetic acid, also referred as Ethanoic acid (C2H4O2), is a simple monocarboxylic acid with a 2-C backbone, as seen in Figure 1.10. “Protic solvent, food acidity regulator, antibacterial food preservative, and daphnia magna metabolite” are some of its functions. It is conjugate acid of acetate [44].
Figure 1.8 Structure of Butanoic acid.
Figure 1.9 Structure of Propanoic acid.
Figure 1.10 Structure of Ethanoic acid.
1.3 Chronology of the Development of Oil and Fats for Industry
Fats and lipids have been regarded as being of utmost importance throughout the history of humankind due to their worth in “food, cosmetics, and natural medicine, as well as many other household applications (such as cooking and candle wax). Vegetable oils and animal fats were used for the first time in Mesopotamia (7000 BC) and ancient Egypt (5000 BC)” [45]. They were employed in cosmetic products like body lotions and oils. These peoples began creating scented oils for mummification, personal cleanliness, medicine, and cosmetics around 2000 BC. “A novel method based on the maceration in oils of flowers, leaves, spices, resins, and occasionally pigments were invented by them [45]. There are surprisingly many different sources of oils, fats, and waxes described in contemporary records. It is evident that even in more prehistoric times, lipid knowledge was more advanced than we think because of the abundance of very common seeds like linseed and poppy seeds, native trees like cedar and palm, fruits like olives and avocados, fish, and even some remarkable animal oils like hippopotamus or crocodile oils [45]. The great Mediterranean societies of the ancient Greeks and Romans adhered to this practice. They introduced new methods for making oils and lotions, like seed pressing and distillation [46]. While the globe was obsessed with the Dark Ages between 400 and 1000 A.D., significant advancements in the use of oils and fats, particularly when applied to medicine and alchemy, were made in various regions of Europe, China, Japan, and North America” [47, 48].
European pharmacopoeia from the medieval and seventeenth centuries both attested to the therapeutic qualities of oils and fats during the Middle Ages [49]. The Industrial Revolution, the development of organic and lipid chemistry, and other factors drastically altered the way that products were produced [50]. Saponification is an illustration of the first novel technique that was widely used throughout the seventeenth and eighteenth century. “The simplest known method of producing soap was heating animal fats or oils with a powerful alkali, adding salts, and then separating the fatty acid salts and glycerol from the final combination [48–50]. The production of soap grew to be a significant industrial-scale business in the second half of the eighteenth century” [50].
As chemistry as a whole developed during the “eighteenth and nineteenth-centuries, so did our understanding of the biological characteristics and uses of fats. As a result, new industrial uses and applications for fatty acids were gradually developed”. As a result, there was a constant quest for fresh and interesting natural sources of fatty acids [46]. At that time, “men began hunting sperm whales as it was termed later, a highly rich supply of fats and an industry of oils at its day. They were the largest toothed whales at the period, distinguished by their enormous skull, which was covered in a waxy material known as spermaceti [51]. This extremely valuable oil is derived from the blubber and acoustic fat bodies, which are now understood to be crucial for whale signal transmission” [52].
At the start of the nineteenth century, the spermaceti oil was attractive to the fats industry because of its adaptability and abundance; candles, soaps, and cosmetics were all made with the congealed form [51, 52]. “By the end of 1958, over 20,000 sperm whales were killed annually, and their waxy oil was used to make cattle fodder, dog food, vitamins, supplements, glue, leather preservatives, and brake fluids [51]. The whaling industry experienced a decline from 1880 until 1925 before increasing once more during World War II. Because of the sharp decline in whale populations, whaling was banned in 1982. The number of sperm whales has dropped from approximately one million to barely a few hundred thousand since whaling began. Because whales are crucial for creating phytoplankton, which recycles CO2 from the atmosphere, this resulted in a tremendous loss for the marine ecosystem” [53].
The introduction of new technologies to the industrial manufacturing of fats and oils resulted from the development of knowledge regarding the chemistry of fats and oils in France and Germany in the late 1800s. Three substantial modifications were employed in this sector. Firstly, “switching from oil extraction to chemical solvent (hexane) extraction via mechanical crushing” was a key advancement in this field [50–53]. Secondly, to “improve storage by reducing rancidification of extracted oils by the addition of antioxidants or refrigeration” and lastly, “building on the second advancement by learning how to use hydrogenation procedures to oils, which transformed polyunsaturated oils into the texture of natural fats” [54].
Despite the large production and the export of a variety of polyunsaturated vegetable oils and fats, people of different cultures and nations still consume large amounts of saturated fat on a regular basis. The Tibetans regularly use yak butter. Due to the historical influence of Ayurvedic treatment, coconut oil, butter, and ghee are still consumed throughout the Indian subcontinent. Despite the availability of processed vegetable oils with a modern Western flavour that are less expensive, Chinese people who live in rural areas still prefer lard and other pork-based foods with saturated fats [54]. For the production of traditional soap, vegetable oils were employed. New processes for refining, bleaching, and deodorising oils as well as high-heat oil extraction procedures enabled the “creation of oils with a neutral flavour that could be utilised for a variety of cooking applications as well as soap making in the late 1800s to early 1900s. Due to their low production costs, the new industrially derived oils were extremely easily adapted for usage in domestic and commercial cooking, frying, and baking [50]. Furthermore, the low-cost margarine that was created by hydrogenation rapidly took the place of natural fats like butter, lard, and tallow in cooking and baking “recipes’’ [51]. Alongside these developments, better techniques for protecting and storing the novel polyunsaturated vegetable oils were created [54]. Hydrogenated oil and fat can be produced to resemble natural products in terms of look, texture, and flavour while still being inexpensive. Compared to spreading chilled butter on bread, spreading chilled margarine was significantly simpler. These characteristics made hydrogenated goods appealing, but they also appeared to have certain negative impacts on human organ systems and tissues during the course of the twentieth century [54]. The utilisation of fatty acid sources has changed recently: polyunsaturated fatty acids (PUFAs), which have been found to have positive effects on human health [55], are of particular interest to the cosmetics, pharmaceutical and food industries. “Fatty acids have also been recently valued as an innovative and green source for the production of biofuel and feedstock [55, 56]. PUFAs are mainly produced by marine phytoplankton and contained in fish and seafood, but climate change has dramatically affected the marine ecosystem. This is due to the high level of carbon dioxide emission and ultraviolet (UV) irradiation, both of which have resulted in a decrease in the growth of marine sources and reduced synthesis of PUFAs and slowed down the growth of marine source [57]. Vegetable oils are insufficient to fill the existing gap, and microbial synthesis is too expensive [58, 59]. Fish and vegetable oil sources are insufficient to meet industrial needs, so research in this area has begun to examine the genetic engineering of algae, bacteria, yeasts, seeds, and plants as bioengineered factories to produce PUFAs in greater quantities consistent with the increased global demand” [60].
1.4 Chemistry of Oil and Fats
Tachen, in the late seventeenth century, Scheele, d’Arcet, and Berthollet, in the following eras, and Michel Eugène Chevreul, in the 1823 publication “Chemical Research on Fats of Animal Origin,” were the first to provide a comprehensive understanding of the chemistry of fats and oils [61, 62]. Chevreul demonstrated that “the excess mass produced by the saponification of fatty acids and glycerine was actually the consequence of the combination of water and the elements rather than the fixation of oxygen” [63]. He came to this conclusion by describing triacylglycerols, which are completely formed acids, as a combination of anhydrous glycerine and oils and fats [61, 63].
As stated earlier, fats and oils are structurally the esters of glycerol having three FAs, hence named triglycerides in the food industry, despite their scientific name of triacylglycerols. Although “oils” and “fats” are sometimes used synonymously, they differ between triglycerides in their liquid state at room temperature (referred to as “oils”) and those in their solid condition (referred to as “fats”) [64]. Triacylglycerols are the basic units of countless potential combinations because they are “esters of fatty acids with the trihydric alcohol glycerol (propane-1,2,3-triol)” [65, 66]. As seen in Figure 1.11, their position, i.e., R1, R2, and R3 and the carbon chains they comprise in the FAs are what essentially define their chemical and physical characteristics.
The number or location of the double bonds in the fatty acids, as well as their chain length, serve as primary distinguishing factors. As a result, the same fat can include a variety of FAs, and different fats can have the same FAs [67]. Generally, they fall into one of three categories:
Major FAs, which are the “five most prevalent naturally occurring FAs (palmitic, stearic, oleic, linoleic, and linolenic), present in large quantities and making up nearly 95% of the FAs of oils and fats used in food products or industrial applications”;
Figure 1.11 Schematic representation of triacylglycerol structure having three fatty acid molecules (-COR1, -COR2, and -COR3) attached with a glycerin molecule [65].
Minor FAs, which are “either homologous or isologues of the major ones and are present in dietary or industrial fats as secondary constituents”;
Uncommon FAs, which are “extracted from infrequent sources and are the primary constituents”
[67]
.
The variety of FA molecules is inversely correlated with the number of TAG species, and natural oils and fats are combinations of various forms of triacylglycerols. For instance, cocoa butter only contains three TAG species while having an FA profile that includes three major FA types [68]. In contrast, “the TAG profile of bovine milk fat, which is made up of a wide variety of FAs, contains more than one hundred species [69]. Although TAG molecules make up 95% or more of crude fats and oils, on average, they also contain a variety of minor ingredients that can have an impact on their physico-chemical properties. The greatest amounts are found in free fatty acids and mono- and di-acylglycerols (MAG and DAG, respectively)” [70].
Additionally, non-glyceride molecules often make up 2% or more of crude vegetable oils [66]. Therefore, the physical characteristics of the real-fat systems’ primary constituents and the phase behaviour of the mixtures these compounds created are partly responsible for the “complicated melting, crystallization, crystal morphology, and aggregation behaviour of these systems’’ [71].
Polymorphism and molecular interactions may both disclose the crystallization characteristics of lipids. Lipid crystal polymorphism involves crystallization and subsequent transformation, which are its macroscopic features. Basically, the solid-solid transition temperatures and three polymorphic forms constitutes a TAG molecule [72]. Thus, the sensory properties of items made from fats are significantly influenced by the polymorphism of triglycerides. For instance, due to their significance in explaining the phase behaviour of cocoa butter, the polymorphism of particular TAG types in applications like chocolate has been examined in greater detail [70].
1.5 Properties of Oils and Fats
The sensory qualities and nutritional value of food can be impacted by the physical and chemical properties of oils and fats [74]. The physical and chemical characteristics of fats and oils are covered below.
1.5.1 Physical Properties
Contrary to popular belief, pure fats and oils have no flavour, odour, or colour. Foreign compounds that are “lipid soluble and have been absorbed by these lipids are what give some of them their distinctive colours, smells, and aromas. For instance, the presence of the pigment carotene gives butter its yellow colour, while the chemicals diacetyl and 3-hydroxy-2-butanone (Figure 1.12), which are formed by bacteria in the maturing cream used to make butter, give it its flavour” [75].
Water is heavier than fats and oils, which have densities of roughly 0.8 g/cm3. They act as great “insulators for the body, limiting the loss of heat via the skin since they are poor heat- and electricity-conductors” [73, 75].
1.5.2 Chemical Properties
Oils and fats can participate in a wide range of chemical processes. Due to being “triglycerides as esters, can get hydrolyzed in the presence of an acid, a base, or certain enzymes called lipases. Making soap is a process known as saponification, which involves hydrolyzing fats and oils in the presence of a base”, as shown in Figure 1.13[75].
Today, the majority of soaps are made by hydrolyzing triglycerides (typically derived from coconut oil, tallow or both) with water at a high pressure of 700 lb/in2 (about 50 atm) and temperature of 200°C [75]. Then, using sodium carbonate or sodium hydroxide, the fatty acids are transformed into their sodium salts (soap molecules):
Figure 1.12 Structure of Butane-2,3-dione and 3-hydroxy-2-butanone.
Figure 1.13 Process of Saponification.
One of the earliest organic syntheses used by humans, ordinary soap is a “combination of the sodium salts of several fatty acids (second only to the fermentation of sugars to produce ethyl alcohol). Romans and Phoenicians (600 BCE) both used animal fat and wood ash to make soap. Even so, it wasn’t until the 1700s that soap started to be produced widely. In the past, vast open vats of molten lard or tallow were treated with a tiny overabundance of alkali to create soap. Steam was emitted from the heated mixture as it was being stirred” [73].
After the process of saponification was finished, sodium chloride (NaCl) was added to the mixture to precipitate the soap, which was then removed by filtration and repeatedly rinsed with water [73–75]. Then, extra NaCl was used to reprecipitate it after it had been dissolved in water. The aqueous wash solutions were also used to recover the glycerol that was created during the process. To make scouring soap, pumice or sand are added, and to make fragrant, coloured soaps, scents or dyes are added. A floating soap is created by blowing air through molten soap. Although more expensive, soft soaps manufactured with potassium salts have a finer lather and are more soluble. Shaving creams, shampoos, and liquid soaps all include them [75]. Typically, “body oils, cooking fats, lubricating greases, and other chemicals that function as glues combine with dirt and grime to attach to skin, clothing, and other surfaces. These compounds cannot be removed by washing with water alone since water does not dissolve them. However, soap eliminates them because of the dual nature of soap molecules. The tail dissolves in oils, while the head, which carries an ionic charge (a carboxylate anion), carries an ionic charge and dissolves in water [70–73]. The ionic heads stay in the aqueous phase, the hydrocarbon tails break down in the soil, and the soap transforms the oil into micelles, which are tiny droplets of oil that disseminate throughout the solution. Due to the charged surfaces of droplets, they repel one another and do not agglomerate. The soap-enclosed dirt can be readily rinsed away since the oil is no longer ‘gluing’ the dirt to the soiled surface (skin, fabric, or dish)” [75].
In industrial procedures, the quantity of hydrogenated double bonds is meticulously regulated to provide fats with the correct consistency (pliable and soft). Thus, “canola, corn, and soybean oils-cheap and plentiful-are converted into margarine and cooking fats. For instance, to make margarine, partially hydrogenated oils are combined with water, salt, nonfat dry milk, flavourings, colorings, and vitamins A and D to mimic the appearance, flavour, and nutritional benefits of butter (preservatives and antioxidants are also added) [75]. To keep it from splitting out, the peanut oil in most commercial peanut butter has been partially hydrogenated. By using the original, unprocessed oils on their dishes, consumers might reduce the quantity of saturated fat in their diet, but most people would rather spread margarine on their toast than pour oil on it” [75].
1.6 Applications of Oils and Fats
1.6.1 Oils and Fats in Surfactants Industry
Surfactants are used in virtually every step of oil exploration, exploitation, and processing [76]. An organic chemical known as surfactant, sometimes known as a “surface active agent,” is amphiphilic and contains both hydrophilic groups (polar heads) and hydrophobic groups (nonpolar tails). Both molecules can build up between fluid phases like oil/water or air/water, lowering the surface and interfacial tensions and generating micelles or emulsions. This is one of these compounds’ special qualities and adaptability [77].
Surfactants are used in the formulation of drilling muds that are water- or oil-based, in hydraulic fracturing and cementing fluids, in acidizing oil wells, in increased oil recovery, in preventing corrosion, in oil-water-gas separation, and in the transportation of crude oil. Surfactants have a variety of roles in the extraction of oil and gas, as well as in the formulation of petroleum products downstream and in the clean-up of oil pollution for environmental protection [76]. Natural surfactants are found in crude oil, and their physical and chemical characteristics have both benefits and downsides. On the other hand, petroleum hydrocarbons continue to provide the majority of the hydrophobes, to be functionalized to amphiphilic compounds, as well as ethylene and propylene oxides, necessary to the synthesis of alkoxylated non-ionic [76, 78]. Carbohydrates and fats are an important source of raw materials for the manufacture of surfactants.
1.6.2 Oils and Fats in Food Industry
For many “food products, including confectionery, bakery, ice creams, emulsions and sauces, shortenings, margarine, and other specially crafted items, fats and oils are crucial raw materials and functional ingredients [79]. Fats and oils add flavour to foods and affect the order in which flavour components are released when foods are eaten, in addition to having a lubricating effect and creating a sensation of moistness in the mouth” [80]. They also contribute to tenderness in shortened cakes and by airing batter, fats help to establish texture in cakes.
Oil helps food retain heat, emulsifies or thickens sauces, prevents sticking, and gives food a crisp texture. Olive oil and butter both have a 9 calorie (kcal)/gm content. Reducing the quantity of fat in baked goods lowers calories while also reducing the amount of fat [81, 82]. The texture, stability, spreadability, and mouthfeel of fat crystals are significantly influenced by their melting profiles, as well as other characteristics. The concentration, shape, and interactions of fat crystals impact the texture of goods like chocolate, shortenings, and especially butter. Shortenings are fats that provide pies, bread, pasta, and other foods particular functional qualities (structural integrity, increased shelf-life, softness, texture, mouthfeel, heat transfer, and air incorporation) (McClements & Decker, 2010) [79].
1.6.3 Oils and Fats in Pharmaceuticals
The role that fats and oils, also known as lipids, play in metabolic processes and cell membrane structure, particularly as precursors of signalling eicosanoids and cell membrane transport agents, is one of the most crucial. “In a variety of delivery forms, such as tablets, capsules, suppositories, emulsions (enteral/parenteral), ointments, creams, and lotions, several lipids are used as fillers, binders, lubricants, solubilizers, emulsifiers, and emollients when highly purified and refined to meet pharmaceutical specifications [83]. Bioactive lipids and lipid-soluble micronutrients like fat-soluble vitamins are important in the prevention of disease” [85]. The human body uses sterols and steroids to generate vital hormones like progesterone and testosterone as well as for various therapeutic applications (Pelletier et al., 1995) [84]. Sterols and steroids also have significant effects on cellular processes. The majority of popular vegetable oils include phytosterols. For instance, one of the most popular oils, soybean oil, is said to contain about 0.124% tocopherols and 0.36% sterols. The potential prevention of intestinal reabsorption of circulating cholesterol has been suggested as the mechanism by which phytosterols reduce blood cholesterol. Since stanols, the saturated form of sterols, are said to be more easily digested, they have been used commercially in food products like margarines and as nutritional supplements [83]. Sitostanol, a saturated sitosterol derivative, is the main stanol described for this purpose. Diagnostic imaging, artificial blood, gene delivery, and medical equipment are among more non-direct applications (Hernandez, 2005) [85].
1.6.4 Oils and Fats in Cosmetics
Natural lipids and oils are employed in cosmetics for a variety of reasons. The combination of skin and cosmetic lipids results in emolliency, the imparting of softness and flexibility. If emulsifiers are utilised, moisture may be retained or even added as a result. Other significant advantages of employing lipids in cosmetics include lubricity, adherence, gloss, and colouring [86]. There may occasionally be biochemical advantages. For instance, animals are unable to manufacture critical fatty acids like linoleic acid, which is then transformed to gamma linoleic acid, an anti-inflammatory drug [87].
1.6.5 Oils and Fats in Agriculture (Pesticide/Herbicide Adjuvants)
In the agriculture industry, methyl esters and plant lipids can be used in place of petroleum-based components in herbicide adjuvant formulations [88]. These ingredients are “biodegradable, non-volatile, low in toxicity, and safer for workers while enhancing herbicide activity during application and reducing the overall pesticide burden on the environment” [86].
1.6.6 Oils and Fats as Biodiesel
Vegetable oil was proposed as a possible fuel source in 1980 [87]. The idea of using edible oil as fuel implies that petroleum will be the alternative fuel instead of alcohol and vegetable oil and that non-renewable resources must be replaced by some type of renewable energy [88].
Animal fats, used cooking oil, and plant and vegetable oils can all be used to make biodiesel. Likewise, fungus, microalgae, and algae can be used to make biodiesel. However, oil-bearing plants have received the majority of attention. The selection of feedstock is the initial stage. More than 350 oil-bearing plants have been identified as possible sources for biodiesel production worldwide [89]. The accessibility of a variety of feedstocks is crucial for the manufacture of biodiesel [88, 90, 91]. Low production costs and mass production are the two primary criteria that the feedstock should meet. Biodiesel feedstock production and availability are influenced by climatic factors, regional soil characteristics, geographic locations, and agricultural methods. Four categories of biodiesel feedstocks are distinguished [88, 92–96]:
Waste or recycled oil.
Edible vegetable oils such as rapeseed, palm, sunflower, peanut, coconut oil and soybean.
Animal fats, such as by-products from fish oils, cattle tallow, yellow grease, and chicken fat
[97]
.
Vegetable oils that are not edible, including halophytes, algae, sea mango, jatropha, and karanja [
95
,
98
].
1.6.7 Oils and Fats in Coating and Polymers
Oils and fats form the component of paints and dyes. Because of the “capacity to cross-link or polymerize on surfaces to form water-proof coatings, conjugated oils like linseed, tung, and some fish oils are referred to as drying oils”. These substances are utilised as paints and varnishes when mixed with pigments [89]. The amount of fatty acids still employed in these applications is estimated to be around 450 million lbs today [90, 99].
