Fat-soluble components

Sucrose polyesters have no primary ester bonds and are not digested. As a result, they remain in the oil phase and are not taken up and are excreted with the stools. In the small intestine, they have some effect on the partitioning of fat-soluble components between the emulsion and micellar phase and as a consequence on their absorption. Reduced absorption of fat-soluble vitamins can be avoided by enriching the sucrose polyesters with these vitamins. Their main use is related to the fact that they can replace usual food fats in many prepared foods but that they do not provide for calories. 

Herbal Tinctures Tinctures are liquid extracts of the herb. Tinctures contain ingredients that do not dissolve in water. Tinctures are made by soaking fresh or dried herbs in alcohol, causing their water-and fat-soluble components to concentrate. Alcohol is used to preserve the herbal concentrate for 1 year. Water is used for people who do not consume alcohol. 

Vitamin E, an apolar molecule that is the most important lipid-soluble antioxidant in humans, is not synthesized in our body, but it is acquired by nourishment. Vitamin E is emulsified together with the fat-soluble components of the food and transported in the body. Lipolysis and emulsification of the formed lipid droplets then lead to the spontaneous formation of mixed micelles [61]. 

In the intestinal lumen (Figure 3) where carotenoids are released from the food matrix, cleavage of carotenoproteins and fatty acid esters by carboxylic ester hydrolase, which is secreted by the pancreas, can occur. Carotenoids are then solubilized into lipid micelles. These hydrophobic compounds are thus more efficiently absorbed when accompanied by at least a small amount of fat. The amount of fat for optimal carotenoid absorption seems to differ among carotenoids. For example, lutein esters require more fat for optimal absorption than j8-carotene. These differences have not been quantified for each carotenoid. In addition, the presence of a nonabsorbable, fat-soluble component was shown to... 

Bde salts, cholesterol, phosphoHpids, and other minor components are secreted by the Hver. Bile salts serve three significant physiological functions. The hydrophilic carboxylate group, which is attached via an alkyl chain to the hydrophobic steroid skeleton, allows the bile salts to form water-soluble micelles with cholesterol and phosphoHpids in the bile. These micelles assist in the solvation of cholesterol. By solvating cholesterol, bile salts contribute to the homeostatic regulation of the amount of cholesterol in the whole body. Bile salts are also necessary for the intestinal absorption of dietary fats and fat-soluble vitamins (24—26). 

Sutures are required to hold tissues together until the tissues can heal adequately to support the tensions exerted on the wound duting normal activity. Sutures can be used ia skin, muscle, fat, organs, and vessels. Nonabsorbable sutures are designed to remain ia the body for the life of the patient, and are iadicated where permanent wound support is required. Absorbable sutures are designed to lose strength gradually over time by chemical reactions such as hydrolysis. These sutures are ultimately converted to soluble components that are then metabolized and excreted ia urine or feces, or as carbon dioxide ia expired air. Absorbable sutures are iadicated only where temporary wound support is needed. 

Vitamins are classified by their solubiUty characteristics iato fat-soluble and water-soluble groups. The fat-soluble vitamins A, E, and K result from the isoprenoid biosynthetic pathway. Vitamin A is derived by enzymic cleavage of the symmetrical C q beta-carotene, also known as pro-vitamin A. Vitamins E and K result from condensations of phytyldiphosphate (C2q) with aromatic components derived from shikimic acid. Vitamin D results from photochemical ring opening of 7-dehydrocholesterol, itself derived from squalene (C q). 

With few exceptions, small particles of vegetable foods are generally stripped of their more accessible nutrients during digestion in the GI tract. In this way starch, protein, fat and water-soluble small components (sugars, minerals) are usually well absorbed. This is not always the case, however, for larger food particles or for molecules that cannot diffuse out of the celF tissue. Neither is it the case for the lipid-soluble components. These need to be dissolved in lipid before they can be physically removed from the cell to the absorptive surface, since the cell wall is unlikely to be permeable to lipid emulsions or micelles, and the presence of lipases will strip away the solvating lipid. 

The stability of individual analytes within a matrix material is often quite variable. A good example is shown by NIST SRM 968b fat soluble vitamins and cholesterol in serum. The material must be shipped and stored at -8o°C. The SRM is certified for a range of vitamins, most of which are quite stable at -20°C, or even +4°C, but the beta-carotene and other components are not. It is therefore essential to ensure the material, if the carotene components are of interest, is shipped and stored correctly. 

Experiments with monkeys given intramuscular injections of a mineral oil emulsion with [l-14C] -hexa-decane tracer provide data illustrating that absorbed C-16 hydrocarbon (a major component of liquid petrolatum) is slowly metabolized to various classes of lipids (Bollinger 1970). Two days after injection, substantial portions of the radioactivity recovered in liver (30%), fat (42%), kidney (74%), spleen (81%), and ovary (90%) were unmetabolized -hexadecane. The remainder of the radioactivity was found as phospholipids, free fatty acids, triglycerides, and sterol esters. Essentially no radioactivity was found in the water-soluble or residue fractions. One or three months after injection, radioactivity still was detected only in the fat-soluble fractions of the various organs, but 80-98% of the detected radioactivity was found in non-hydrocarbon lipids. 

Alpha hydroxy acids (AHAs) are water-soluble substances and thereby penetrate the outermost epidermal skin layers. In contrast, beta hydroxy acids (BHAs) are lipid (fat) soluble and are capable of penetrating to the underlying layers of skin (the dermis) located 1-5 mm below the surface of the skinJ2 Most AHAs are derived from plant materials and marine sources. Commonly used AHAs include malic acid (found in apples), ascorbic acid (a common ingredient in numerous fruits), glycolic acid (a constituent of sugar cane), lactic acid (a component of milk), citric acid (naturally abundant in citrus fruits), and tartatic acid (found in red wine). A common BHA is salicylic acid (an ingredient in aspirin). 

The reaction of peroxidase (metmyoglobin) with hydrogen peroxide leads to the generation of a green-blue radical from a colorless compound 2,2 -azino-(u s(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). It is slowed down in the presence of an antioxidant, an effect that is used for its quantitation in the Total Antioxidant Status Kit (manufacturer Randox, UK) [10]. Problems associated with this method are due to potential interference of the reaction compound H202 with components of the sample to be investigated. No investigation of fat-soluble compounds is possible. 

Several lipids are not formed independently in the human body. These substances, as essential fatty acids and fat-soluble vitamins, are indispensable components of nutrition (see pp.364ff.)... 

A. Digestion and intestinal absorption of fat-soluble dietary components... 

Many different kinds of milk and milk products are available (USDA 1978 NDC 1976,1983A, 1983B). Milk has two major components fat, including fat-soluble vitamins, and milk-solids-not-fat (MSNF), which contain protein, carbohydrate, water-soluble vitamins, and minerals. The specific nutrient contribution of each of these milk products is related largely to the concentrations of milk fat and MSNF of the product. If the percentages of milk fat and MSNF are known, the values in Table 7.2 may be used to determine the nutrient contribution of a particular milk product. 

Vitamin A is necessary for growth and reproduction, resistance to infection, maintenance and differentiation of epithelial tissues, stability and integrity of membrane structures, and the process of vision. In terms of the last function, vitamin A is a component of rhodopsin or visual purple, a photosensitive pigment in the eye that is needed for vision in dim light. An early mild clinical symptom of vitamin A deficiency is night blindness a severe deficiency of this fat-soluble vitamin results in xerophthalmia, an eye condition leading to blindness. 

Components of the electron transport chain in bacteria have been shown to include b- and c-type cytochromes, ubiquinone (fat-soluble substitute quinone, also found in mitochondria), ferredox (an enzyme containing nonheme iron, bound to sulfide, and having the lowest potential of any known electron-canying enzyme) and one or more flavin enzymes. Of these a cytochrome (in some bacteria, with absorption maximum at 423.5 micrometers, probably Cj) has been shown to be closely associated with the initial photoact. Some investigators were able to demonstrate, in chromatium, the oxidation of the cytochrome at liquid nitrogen temperatures, due to illumination of the chlorophyll. At the very least this implies that the two are bound very closely and no collisions are needed for electron transfers to occur. 

Methods of extracting the fat-soluble vitamin from food matrices include alkaline hydrolysis, enzymatic hydrolysis, alcoholysis, direct solvent extraction, and supercritical fluid extraction of the total lipid component. 

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