File Name: fats and oils chemistry .zip
- Standard Methods for the Analysis of Oils, Fats and Derivatives
- Dietary fat
- 17.2: Fats and Oils
- Lipid chemistry and dietary fats
This book is composed of two sections. The first section deals with the presentation of standard methods and procedure for oleaginous seeds and fruits analysis of oil, fats, and their derivatives. The next section describes the determination procedure of physico-chemical properties of determined oil, fats, and derivatives.
Handbook of Food Chemistry pp Cite as. Fats and oils are an important dietary component and contribute to the nutritional and sensory quality of foods. This chapter focuses on the chemical composition of fats and oils and how these compositions affect the functional properties of fats and oils in foods. The focus will remain on the most economically and commercially important fats and oils that are widely used as or in food products.
Standard Methods for the Analysis of Oils, Fats and Derivatives
Lipid , any of a diverse group of organic compounds including fats , oils , hormones , and certain components of membranes that are grouped together because they do not interact appreciably with water. One type of lipid, the triglycerides , is sequestered as fat in adipose cells , which serve as the energy-storage depot for organisms and also provide thermal insulation. Some lipids such as steroid hormones serve as chemical messengers between cells , tissues , and organs , and others communicate signals between biochemical systems within a single cell.
The membranes of cells and organelles structures within cells are microscopically thin structures formed from two layers of phospholipid molecules. Membranes function to separate individual cells from their environments and to compartmentalize the cell interior into structures that carry out special functions. So important is this compartmentalizing function that membranes, and the lipids that form them, must have been essential to the origin of life itself.
A lipid is any of various organic compounds that are insoluble in water. Together with proteins and carbohydrates , lipids are one of the principal structural components of living cells.
Lipids are a diverse group of compounds and serve many different functions. At a cellular level, phospholipids and cholesterol are some of the primary components of the membranes that separate a cell from its environment.
Lipid-derived hormones, known as steroid hormones , are important chemical messengers and include testosterone and estrogens. At an organismal level triglycerides stored in adipose cells serve as energy-storage depots and also provide thermal insulation. Lipid rafts are possible areas of the cell membrane that contain high concentrations of cholesterol and glycosphingolipids. The existence of lipid rafts has not been conclusively established, though many researchers suspect such rafts do indeed exist and may play a role in membrane fluidity, cell-to-cell communication, and infection by viruses.
Water is the biological milieu—the substance that makes life possible—and almost all the molecular components of living cells, whether they be found in animals, plants, or microorganisms, are soluble in water. Some lipids are amphipathic—part of their structure is hydrophilic and another part, usually a larger section, is hydrophobic.
Amphipathic lipids exhibit a unique behaviour in water: they spontaneously form ordered molecular aggregates , with their hydrophilic ends on the outside, in contact with the water, and their hydrophobic parts on the inside, shielded from the water. This property is key to their role as the fundamental components of cellular and organelle membranes. Although biological lipids are not large macromolecular polymers e.
Many of these molecular building blocks are similar, or homologous, in structure. The homologies allow lipids to be classified into a few major groups: fatty acids, fatty acid derivatives, cholesterol and its derivatives, and lipoproteins.
This article covers the major groups and explains how these molecules function as energy-storage molecules, chemical messengers, and structural components of cells. Fatty acids rarely occur as free molecules in nature but are usually found as components of many complex lipid molecules such as fats energy-storage compounds and phospholipids the primary lipid components of cellular membranes. This section describes the structure and physical and chemical properties of fatty acids.
It also explains how living organisms obtain fatty acids, both from their diets and through metabolic breakdown of stored fats. Biological fatty acids, members of the class of compounds known as carboxylic acids , are composed of a hydrocarbon chain with one terminal carboxyl group COOH. The fragment of a carboxylic acid not including the hydroxyl OH group is called an acyl group. Most biological fatty acids contain an even number of carbon atoms because the biosynthetic pathway common to all organisms involves chemically linking two-carbon units together although relatively small amounts of odd-number fatty acids do occur in some organisms.
Although the molecule as a whole is water-insoluble by virtue of its hydrophobic hydrocarbon chain, the negatively charged carboxylate is hydrophilic. This common form for biological lipids—one that contains well-separated hydrophobic and hydrophilic parts—is called amphipathic.
In addition to straight-chain hydrocarbons, fatty acids may also contain pairs of carbons linked by one or more double bonds, methyl branches, or a three-carbon cyclopropane ring near the centre of the carbon chain. Lipid Article Media Additional Info. Article Contents. Print print Print. Table Of Contents. While every effort has been made to follow citation style rules, there may be some discrepancies.
Please refer to the appropriate style manual or other sources if you have any questions. Facebook Twitter. Give Feedback External Websites. Let us know if you have suggestions to improve this article requires login. External Websites. Thomas E. See Article History. Structure and properties of two representative lipids. Lipid molecules of this composition spontaneously form aggregate structures such as micelles and lipid bilayers, with their hydrophilic ends oriented toward the watery medium and their hydrophobic ends shielded from the water.
Top Questions. A false colour transmission electron microscope micrograph of an oogonium an egg cell of certain algae and fungi , showing an abundance of lipid droplets yellow , a nucleus green , an atypical nucleolus dark blue , and mitochondria red. Get a Britannica Premium subscription and gain access to exclusive content.
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In biology and biochemistry , a lipid is a macro biomolecule that is soluble in nonpolar solvents. The functions of lipids include storing energy, signaling , and acting as structural components of cell membranes. Biological lipids originate entirely or in part from two distinct types of biochemical subunits or "building-blocks": ketoacyl and isoprene groups. Although the term "lipid" is sometimes used as a synonym for fats , fats are a subgroup of lipids called triglycerides. Lipids also encompass molecules such as fatty acids and their derivatives including tri- , di- , monoglycerides , and phospholipids , as well as other sterol -containing metabolites such as cholesterol.
17.2: Fats and Oils
Victorian government portal for older people, with information about government and community services and programs. Type a minimum of three characters then press UP or DOWN on the keyboard to navigate the autocompleted search results. Foods and drinks contain nutrients such as carbohydrates , proteins, fats, vitamins and minerals. Some foods or drinks contain a large amount of one nutrient such as soft drink, which contains a large amount of sugar, or fried food, which contains a large amount of fat. Dietary fat fat in foods and drinks , is important for many body processes.
Lipid chemistry and dietary fats
While we are building a new and improved webshop, please click below to purchase this content via our partner CCC and their Rightfind service. You will need to register with a RightFind account to finalise the purchase. As part of these celebrations, we are offering free access to the virtual issue of PAC: 60 seminal papers published in PAC over the past 60 years. Pure and Applied Chemistry is the official monthly Journal of IUPAC, with responsibility for publishing works arising from those international scientific events and projects that are sponsored and undertaken by the Union. The policy is to publish highly topical and credible works at the forefront of all aspects of pure and applied chemistry, and the attendant goal is to promote widespread acceptance of the Journal as an authoritative and indispensable holding in academic and institutional libraries.
Fats and oils are the most abundant lipids in nature. They provide energy for living organisms, insulate body organs, and transport fat-soluble vitamins through the blood. Fats and oils are called triglycerides or triacylcylgerols because they are esters composed of three fatty acid units joined to glycerol , a trihydroxy alcohol:. If all three OH groups on the glycerol molecule are esterified with the same fatty acid, the resulting ester is called a simple triglyceride. Although simple triglycerides have been synthesized in the laboratory, they rarely occur in nature. Instead, a typical triglyceride obtained from naturally occurring fats and oils contains two or three different fatty acid components and is thus termed a mixed triglyceride.
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Structures of Fats and Oils
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