Nutritional components

Sedentary adults in a temperate climate need to consume about 21 of water per day, a figure that can substantially increase when high temperature and/or physical activity causes significant sweating. Soft drinks and fruit juices provide a valuable water source, as shown in Table 13.1. 

With the exception of soda waters and most low-calorie drinks, all soft drinks rely at least partially on sugars to provide sweetness and body. 

Although different sugars have different sweetness factors relative to sucrose they are all identical in energy content, on a dry basis. Thus to achieve a high energy content without cloying sweetness, sugars or carbohydrates of low sweetness must be used. This is illustrated in Table 13.2. 

Carbohydrate Sweetness, relative to sucrose kcal required to provide the same sweetness as 1 g sucrose 

Most soft drinks contain less carbohydrate than fruit juices, although this is not the perception of the consumer (Table 13.3). 

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The importance of the basal medium in culturing normal cells was demonstrated by Dr. Richard Ham (Ham and McKeehan, 1979). Dr. Ham s laboratory developed a number of different types of culture media, in which the concentrations of the individual nutritional components have been optimized to support the growth of specific types of normal, differentiated cells. The most widely used is nutrient mixture FI2, which contains nonessential, as well as essential, amino acids, a number of lipids, and trace elements (Table 5). 

Enzymatic maceration, which is a softening of plant tissue by the use of enzymes, has some potential quality advantages over mechanical-thermal disintegration as maceration is obtained with less damage to the cell walls. The major part of the plant cells remains intact by enzymatic maceration [25], as the enzymes attack only the space between the cells, and with only rare injury to the cell membrane [26]. The intact cells protect nutritional components within the cells which minimise flavour changes and deterioration on storage [27,28]. 

A. I. Popov and O. G. Chertov, On humic substances as a direct nutritive component of plant-soil trophic system. The Role of Humic Substances in the Ecosystems and in Environmental Protection ( J. Drozd, S. S. Gonet, N. Senesi, and J. Weber, eds.), Polish Society of Humic Substances, Wroclaw, 1997, p. 993. 

Corral-Aguayo R, Yahia EM, Carrillo-Lopez A and Gonzalez-Aguilar G. 2008. Correlation between some nutritional components and the total antioxidant capacity measured with six different assays in eight horticultural crops. J Agric food Chem 56 10498-10504. 

Syngletary KW, Jackson SJ, Milner JA. 2005. Non-nutritive components in foods as modifiers of the cancer process. In Bendich A and Deckelbaum RJ, editors. Preventive Nutrition the Comprehensive Guide for Health Professionals, 3rd ed. Totowa, NJ Humana Press. 

The current trend is to move away from compositional legislation to a much freer approach in which carbohydrates and other nutritional components can be used at will and additives are taken from positive lists of functional components. Other ingredients are frequently controlled by negative usage (i.e. they must not be present or must not exceed closely defined limits). 

Paradoxically, the nutritional component of greatest commercial significance is the absence of nutrition, achieved by substituting carbohydrate sweeteners with non-nutritive sweeteners such as saccharin and acesulfame-K, or the amino acid sweetener aspartame. 

Animal experiments have shown that faulty nutrition, i.e. > 90% fat, < 10% protein and < 2 mg choline per day, leads to pronounced fatty fiver and even fatty cirrhosis within a few weeks. The same changes could be observed when the protein intake remained more or less normal, while extremely little methionine and choline was offered. With a partial surplus of certain foodstuffs, the special nature of the excessive nutritional components is also of considerable importance. The term partial malnutrition may, for example, be associated with a pronounced protein deficiency (and thus possibly inadequate production of lipoproteins) or a lack of lipotropic substances (such as methionine, choline, cystine, glycocoUbetaine, pyridoxine, casein and various N- or S-methylated substances). Protein deficiency has particularly severe consequences when toxic substances are absorbed at the same time or when the organism has to fight bacterial or parasitic infections. A diseased liver reacts to both a serious deficiency in and an excessive supply of different nutrients (e.g. proteins, certain kinds of amino acids, various lipids, trace elements) with unfavourable or even complicative developments during the course of disease. 

The prognosis is determined by the early onset of acute liver failure in the newborn and, in the following months or years, by the development of hepatocellular carcinoma. (163, 167) A liver transplantation is thus recommended as from the second or third year of life. (162) Dietary measures (avoidance of methionine, tyrosine and phenylalanine as nutritional components) have not proved particularly successful. Good therapeutic results were achieved when 2-(2-nitro-4-trifluoromethyl-benzoyl)-l-3-cyclohexanedione) (NTBC) was applied. This substance is an inhibitor of 4-hydroxyphenylpyru-vate dioxygenase, which prevents the accumulation of succinylacetone. (165) Even the risk of HCC development was reduced by this substance. 

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