Lipid energy value

Foods differ in their energy value, which is usually expressed in kilocalories or kilojoules, with proteins and carbohydrates having less caloric value than fats (lipids). Fats... 

Lipids are another type of biomolecule that are very important for life. There are many different kinds of lipids with very different chemical properties, but they all share the property of being insoluble in water. Examples of lipids include fats, oils, waxes, and steroids. Lipids make up the membranes that surround cells. Fats are one of the major food groups because of their very high energy value. 

The primary supposition of any toxicological QSAR is that the potency of a compound is dependent upon its molecular structure, which is typically quantified by chemical properties (Schultz et al., 2002). Chemical descriptors include a variety of types, including atom, substituent, and molecular parameters. The most transparent of these are the molecular-based empirical and quantum chemical descriptors. Empirical descriptors are measured descriptors and include physicochemical properties such as hydrophobicity (Dearden, 1990). Quantum chemical properties are theoretical descriptors and include charge and energy values (Karelson et al., 1996). Physicochemical and quantum chemical descriptors are for the most part easily interpretable with regard to how that property may be related to toxicity. The classic example of this, the partitioning of a toxicant between aqueous and lipid phases, has been used as a measure of hydrophobicity for over a century (Livingstone, 2000). 

The lipid with the lowest energy value for human nutrition is ... 

Energy Value of Lipids Essential Fatty Acids Structural Components Regulatory Functions... 

FA are the dietary components that account for the amount of energy liberated during oxidation of lipids in the body. Glycerol is approximately 10% by weight of TAG but accounts for only 5% of the energy. The FA of food impart the high energy value that is of nutritional interest. 

The composition and energy values of experimental diets are shown in Table 5. The low-fat diet (LF) contained 5% lipids, whereas the high-fat diet (HF) contained 30% lipids and 13% sucrose. The energy values of the LF and HF diets were 399.7 and 522.2 kcaFlOO g, respectively. The HF diet had 30% more energy than the LF diet. The ALA-DAG-added diets were prepared by addition of 1,2, and 4% ALA-DAG to the basic HF diet. 

Fat is needed in human nutrition for growth and replacement of tissues, for certain lipid secretions, and as a source of energy. The optimal level of fat in the diet is not known, and since fat may be formed from carbohydrate or protein, no definite requirement can be formulated. Fat increases the palatability of the diet and also reduces the bulk, since the energy value of fat is more than twice that of an equivalent amount of protein or carbohydrate. Dietary fat also acts as a carrier for the fat-soluble vitamins. 

K = 63 M 1, Kb = 1.4M-1)47 lithium-7 (K = 14 M 1 K" = 0.5 M 1) 49) and for cesium-133 (K, st 50 M-1, K = 4M 1)S0). In the case of sodium-23, transverse relaxation times could also be utilized to determine off-rate constants k ff = 3 x 105/sec k"ff = 2x 107/sec47,51). Therefore for sodium ion four of the five rate constants have been independently determined. What has not been obtained for sodium ion is the rate constant for the central barrier, kcb. By means of dielectric relaxation studies a rate constant considered to be for passage over the central barrier, i.e. for jumping between sites, has been determined for Tl+ to be approximately 4 x 106/sec 52). If we make the assumption that the binding process functions as a normalization of free energies, recognize that the contribution of the lipid to the central barrier is independent of the ion and note that the channel is quite uniform, then it is reasonable to utilize the value of 4x 106/sec for the sodium ion. 

Toxic compounds polychlorinated biphenyls, polycyclic aromatic hydrocarbons, organochlorine pesticides, chlorinated pesticides, dioxins, veterinary drug residues, hormone residues, aflatoxins, toxic compounds in shellfish. Compoimds of nutritional significance in foods vitamins, fat, lipids, carbohydrates, protein, energy-calorific value, proximates, dietary fibre, ash. Other compounds hormones in blood serum... 

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