Nutrition and Chemistry

Natural and synthetic compounds with vitamin A activity and inactive synthetic analogues of vitamin A are collectively termed retinoids. The most biologically active. 

Chemical structure of a -tmns retinol (vitamin Ai), the most active form of vitamin A. Oxidation of C15 to an aldehyde or an acid produces, respectively, retinaldehyde (retinal) and retinoic acid. The cis-trans isomerization of the double bond between Ci i and C12 occurs during functioning of retinaldehyde in vision. 

Retinyl esters are hydrolyzed in the intestinal lumen by pancreatic carboxylic ester hydrolase, which also hydrolyzes cholesteryl esters. In mucosal cells, retinol is reesterified, mostly with long-chain fatty acids, by 

In the liver, retinyl esters are hydrolyzed and reesterified. More than 95% of hepatic retinol is present as esters of long-chain fatty acids, primarily palmitate. In an adult receiving the RDA of vitamin A, a year s supply or more may be stored in the liver. 

More than 90% of the body s supply of vitamin A is stored in the liver. The hepatic parenchymal cells are involved in its uptake, storage, and metabolism. Retinyl esters are transferred to hepatic fat-storing cells (also called Ito cells or lipocytes) from the parenchymal cells. The capacity of these fat-storing cells may determine when vitamin A toxicosis becomes symptomatic. During the development of hepatic fibrosis (e.g., in alcoholic liver disease), vitamin A stores in Ito cells disappear and the cells differentiate to myofibroblasts. These cells appear to be the ones responsible for the increased collagen synthesis seen in fibrotic and cirrhotic livers. 

---

With the extensive knowledge available in oil chemistry, development of designer fats and oils is possible (34). This is of special interest to nutritionists who see the possibiUties for stmcturaHy designed fats to meet developing knowledge in clinical nutrition and food product development. 

KRISTENSEN D, krOger-ohlsen m V and SKIBSTED L H (2002) Radical formation in dairy products Prediction of oxidative stability based on electron spin resonance spectroscopy, in Morello M J, Shahidi F Ho CT Free Radicals in Food, Chemistry, Nutrition and Health Effects, ACS Symposium Series 807, Washington D C, 114-25. 

Analytical chemistry is an important field in the life sciences whether the main focus is health (pharmaceutical chemistry), nutrition (food chemistry), food supply (pesticide chemistry), environment (water chemistry, waste minimization, disposal or treatment) or lifestyle (textiles, mobility, cosmetics). Thus chemists (and other scientists) working analytically, whether they are trained originally as analytical chemists or whether they come from a different field and use analytical chemistry as support for their research area, play an important role in supporting the progress in the life sciences. 

The analysis of the methylxanthines (caffeine, theobromine, and theophylline) is important in the areas of nutrition and clinical chemistry. These three compounds compose the majority of the alkaloids present in coffee, tea, cocoa, cola nuts, and guarana. 

Because composition and nutritional properties of the major food legumes and oilseeds have been reported in numerous technical journals and books (listed above), the section devoted to composition and chemistry highlights lesser-known but potentially important sources of plant protein that have not received the same attention. Some of these food crops have been cultivated for many years so that they are not "new" sources. Such crops as winged bean, sweet potato, tropical seeds, fruits and leaves, yams and cucurbits are potential sources of protein in areas where they are grown. These are discussed in greater detail in the remaining five chapters. 

Govindarajan V, Sathyanarayana M (1991) Capsicum - production, technology, chemistry, and quality. Part V - Impact on physiology, pharmacology, nutrition and metabolism structure, pungency, pain and desensitization sequences. Ciit Rev Food Sci Nutr 29 435 74... 

Having a balanced chemical equation and knowing the relationship between mass and moles allows us to predict how much reactant is necessary to yield a certain amount of product. This knowledge has important applications in industrial chemistry, environmental chemistry, nutrition, and in any situation where reactions take place. The balanced equation is a recipe for a chemical reaction. Just as it is necessary to know the amount of eggs, flour, sugar, and salt to bake a cake, we need to know the amount of ingredients that go into a chemical reaction. The balanced chemical equation gives the quantities of different reactants that are required to produce a specific amount of product. 

The cited observations suggest that it is possible to identify potato cultivars with low or high phenolic acid content for human use and to select processing conditions that minimize losses of phenolic compounds. In summary, the methods we developed and used to determine the content and distribution of phenolic compounds in potato plant flowers, leaves, and tubers, in the peel and flesh parts of potato tubers, and in freeze-dried and processed commercial potatoes merit application in numerous studies designed to assess the role of potato phenolic compounds in host-plant resistance, plant breeding, plant molecular biology, food chemistry, nutrition, and medicine. The described wide distribution of phenolic compounds in different commercial... 

Fundamentals of Dairy Chemistry has always been a reference text which has attempted to provide a complete treatise on the chemistry of milk and the relevant research. The third edition carries on in that format which has proved successful over four previous editions (Fundamentals of Dairy Science 1928, 1935 and Fundamentals of Dairy Chemistry 1965, 1974). Not only is the material brought up-to-date, indeed several chapters have been completely re-written, but attempts have been made to streamline this edition. In view of the plethora of research related to dairy chemistry, authors were asked to reduce the number of references by eliminating the early, less significant ones. In addition, two chapters have been replaced with subjects which we felt deserved attention Nutritive Value of Dairy Foods and Chemistry of Processing. Since our society is now more attuned to the quality of the food it consumes and the processes necessary to preserve that quality, the addition of these topics seemed justified. This does not minimize the importance of the information in the deleted chapters, Vitamins of Milk and Frozen Dairy Products. Some of the material in these previous chapters has been incorporated into the new chapters furthermore, the information in these chapters is available in the second edition, as a reprint from ADSA (Vitamins in Milk and Milk Products, November 1965) or in the many texts on ice cream manufacture. 

Shahidi, F. and Wanasundara, U. 1998. Methods of measuring oxidative rancidity in fats and oils. In Food Lipids. Chemistry, Nutrition, and Biotechnology (C.C. Akoh and D.B. Min, eds.) pp. 377-396. Marcel Dekker, New York. 

Food Lipids Chemistry, Nutrition, and Biotechnology, edited by Casimir C. Akoh and David B. Min... 

Nutritionally, the most important water-soluble vitamins in citrus fruits are ascorbic acid, folic acid and pyridoxine. Clinical studies on the bioavailability of these vitamins, as well as basic research on the absorption and chemistry of these vitamins, have yielded valuable information adding to our overall understanding of the nutritional quality and bioavailability of these vitamins found in citrus fruits. 

Friedman, M. (1999) Chemistry, nutrition, and microbiology of D-amino acids./. Agric. Food Chem., 47, 3457. 

Department of Analytical Chemistry, Nutrition, and Bromatology University of Santiago de Compostela Santiago de Compostela, Spain... 

Friedman, M. 1999a. Chemistry, biochemistry, nutrition, and microbiology of lysinoala-nine, lanthionine, and histidinoalanine in food and other proteins. J Agric Food Chem 47 1295-1319. 

Feeney, R.E., Whitaker, J.R. (eds) 1982. In Modification of Proteins Food, Nutritional, and Pharmacological Aspects , Advances in Chemistry Series 198. American Chemical Society, Washington, DC. 

Chemical modification of proteins is an important everyday tool of basic protein chemistry. Its role in applied protein chemistry appears to be increasing and branching into different areas such as food, nutrition, and pharmacology. 

W. Hoffmann Federal Research Centre for Nutrition and Food, Location Kiel, Hermann-Weigmann-Str. 1, D- 24103 Kiel. Telephone +49 (0) 431 609 2272, Fax +49 (0) 431 609 2309, E-Mail wolfgang.hoffmann bfel.de W. Buchheim Lornsenstr. 34, D- 24105 Kiel. Advanced Dairy Chemistry, Volume 2 Lipids, 3rd edition. Springer, New York, 2006. 

Shahidi, F., and Wanasundara, U. N. 1998. Methods of Measuring Oxidative Rancidity in Fats and Oils. In, Food Lipids Chemistry, Nutrition and Biotechnology Food Science and Technology Series (vol. 88, pp. 377-396). New York Marcel Dekker. 

---