Fat substitutes from carbohydrates

What would be the structures of the monosaccharide esters obtained from hydrolysis of Olestra ( A Word about Fat Substitutes from Carbohydrates, page 482) with an aqueous acid ... 

Suggest a synthesis of Olestra (see A Word About... Fat Substitutes from Carbohydrates, on page 482) starting from sucrose and lauric acid. 

Much research is currently underway to determine whether a correlation exists between cholesterol levels in the blood and diet. Cholesterol not only comes from the diet, but is also synthesized in the body from carbohydrates and proteins as well as fat. Therefore, the elimination of cholesterol rich foods from the diet does not necessarily lower blood cholesterol levels. Some studies have found that if certain unsaturated fats and oils are substituted for saturated fats the blood cholesterol level decreases. 

Fat mimetics used in industry are macromolecules similar to conventional fats and oils with respect to their physical and chemical properties. They are chemically synthesized or extracted from traditional fats and combined with other components such as saccharose. Commercially available carbohydrate fat substitutes include DDA (fat ester of malonic and alkyl-malonic acids) and Olean (Olestra, a mixture of octa-, hepta-, and hexa-esters of saccharose). 

Hu and Stampfer [53] also estimated that substimting 1 ounce (-28.35 g) of nuts for the equivalent energy from carbohydrate in an average diet was associated with a 30% reduction in CHD risk. The substitution of nut fat for saturated fet was associated with a 45% reduction in risk. Hu and Stampfer [53] concluded regular nut consumption can be recommended in the context of a healthy and balanced diet. 

A possibly different type of reserve protein which should be mentioned in this connection, is that which is retained together with water and electrolyte, when carbohydrate is isocalorically substituted for fat in the diet at any level, the protein intake being unchan. This phenomenon was first clearly demonstrated by Hellesen (144) and was subsequently studied by Cathcart and his pupils (12). The reverse process, loss of fluid, electiol3Tte and labile protein reserve, occurs when fat is substituted for carbohydrate. The phenomenon is clearly seen in the classical experiments of Atchl, Loeb et al. (145) on withdrawal of insulin from diabetic patients. From the start of insulin withdrawal, as fat combustion replaced that of carbohydrate, there occurred an increased loss of fluid, eledrolyte and nitrogen in the urine. 

Activator of certain enzymes—Chromium is the spark plug which fires up certain enzymes into vigorous metabolic activity. Most of these enzymes are involved in the production of energy from carbohydrates, fats, and proteins. However, some of these enzymes may also be activated by other metal elements such as aluminum, iron, manganese, and tin. Similarly, chromium activates the digestive enzyme trypsin although here, too, other metals may act as substitutes. Hence, the activities of these enzymes may not be noticeably depressed when there is a chromium deficiency. 

A recent application of completely or nearly completely esterified carbohydrates is the formation of fat substitutes such as Olestra (a sucrose product from Procter and Gamble), which is obtained by transesterification of seven or eight fatty acids from soybean or cottonseed edible oils. 

There are three types of fat substitutes carbohydrate-based, protein-based, and fat-based. The carbohydrate-based fat substitutes appeared first on the market in the 1960s, and the protein-based substitutes followed in the late 1980s. Modified starches, gums, and proteins, chopped into tiny pieces ranging from 100 to 3000 nm, make up most of the fake fats on the market. For example, NutraSweet manufactures Simplesse, a whey-protein concentrate most often found in dairy and oil-based foods such as ice cream and salad dressing. 

Biochemistry is carbonyl chemistiy. Almost all metabolic pathways used by living organisms involve one or more of the four fundamental carbonvl-group reactions we ve seen in Chapters 19 through 23. The digestion and metabolic breakdown of all the major classes of food molecules—fats, carbohydrates, and proteins—take place by nucleophilic addition reactions, nucleophilic acyl substitutions, a substitutions, and carbonyl condensations. Similarly, hormones and other crucial biological molecules are built up from smaller precursors by these same carbonyl-group reactions. 

In defining the nutritional equivalence of dairy foods, FDA considered only 11 to 15 nutrients for milk substitutes, 1 nutrient for cream substitutes, and 4 to 9 nutrients for cheese substitutes (FDA 1978). Yet, data from the Consumer and Food Economics Institute, USDA (1976), reveal that traditional milk, cream, and cheese contain an array of nutrients including protein, fat, carbohydrate, and at least 15 minerals and vitamins and 18 amino acids. Thus, under FDA s proposal (FDA 1978), which has been withdrawn (FDA 1983) but, as mentioned above, may in effect be applied, a substitute dairy product could be declared nutritionally equivalent to its traditional counterpart and yet (1) not contain all of the nutrients in the traditional food, or (2) contain some or all of these other nutrients but in lesser quantities, or (3) contain some of the nutrients such as sodium in excessive amounts, or (4) contain more or less energy (NDC 1983C). 

To treat the malabsorption and subsequent diarrhea, lipid-poor diets (<5 g/day) should be implemented with a restriction of triglycerides containing long-chain fatty acids. Medium-chain fatty acids rely on other protein carriers besides apoB (i.e., albumin) for plasma transport, making them an ideal lipid substitute. However, long-term supplementation should be cautioned as associated hepatic fibrosis could occur. Diets should also contain increased protein and carbohydrate content to compensate for caloric loss from fat restriction. 

The response to a diet may change when the proportions of energy supplied as carbohydrates and fat are varied. For example, an animal may increase its consumption of food when carbohydrates are substituted in place of an equal weight of fat. This increase is due to the animaTs desire to satisfy its energy requirement. The increase in food consumption results in increases in the intake of protein, vitamins, and minerals, and thus their possible oversupply. A solution to the problem of comparing physiological responses to diets of different carbohydrate/fat ratios is available. The equivalent of 1 kj of carbohydrate can be omitted from the diet and replaced by 1 kJ of fat plus nonnutritive fiber, where the weights of the carbohydrate and fat -i- fiber are identical. This type of substitution maintains the nutrient density of all the other nutrients (Harper, 1986). 

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