Sugar Energy

Saris WHM (2003) Sugars, energy metabolism, and body weight control. American Journal of Clinical Nutrition 78(supple-ment) 850S-857S. 

Pasteur effect Yeast and other cells can break down sugar in the presence of oxygen (eventually to CO2 and H2O) or in its absence (to CO2 and ethanol). The decomposition of sugar is often greater in the absence of oxygen than in its presence, i.e. the Pasteur effect. With oxygen, less toxic products (alcohol) are produced and the breakdown is more efficient in terms of energy production. 

The major classes of organic compounds common to living systems are lipids pro terns nucleic acids and carbohydrates Carbohydrates are very familiar to us— we call many of them sugars They make up a substantial portion of the food we eat and provide most of the energy that keeps the human engine running Carbohy drates are structural components of the walls of plant cells and the wood of trees Genetic information is stored and transferred by way of nucleic acids specialized derivatives of carbohydrates which we 11 examine m more detail m Chapter 28... 

The FAB source operates near room temperature, and ions of the substance of interest are lifted out from the matrix by a momentum-transfer process that deposits little excess of vibrational and rotational energy in the resulting quasi-molecular ion. Thus, a further advantage of FAB/LSIMS over many other methods of ionization lies in its gentle or mild treatment of thermally labile substances such as peptides, proteins, nucleosides, sugars, and so on, which can be ionized without degrading their. structures. 

The manufacture of sugar was early understood to be an energy-intensive process. Cuba was essentially deforested to obtain the wood that fueled the evaporation of water from the cane juice. When the forests were gone, the bagasse burner was developed to use the dry cane pulp, called bagasse, for fuel. Bagasse was no longer a waste product its minimal value is the cost of its replacement as fuel. 

A cane factory generates its own requirements for energy, from burning bagasse to produce electricity one tonne of mill mn bagasse (50% moisture) is equivalent in fuel value, at 3,700 kj /kg (884 kcal/kg), to one barrel (159 L) of fuel oil. An efficient raw sugar or plantation white factory will use 70—80%... 

Sugar production costs energy, labor, and materials... 

The creation of sugar in the leaves of natural plants is considered the most efficient way of capturing solar energy. Table 1 illustrates the area of land needed to capture 27.7 x 10 kj (6.61 x 10 kcal) of solar energy (2) in various food products. 

The elemental and vitamin compositions of some representative yeasts are Hsted in Table 1. The principal carbon and energy sources for yeasts are carbohydrates (usually sugars), alcohols, and organic acids, as weU as a few other specific hydrocarbons. Nitrogen is usually suppHed as ammonia, urea, amino acids or oligopeptides. The main essential mineral elements are phosphoms (suppHed as phosphoric acid), and potassium, with smaller amounts of magnesium and trace amounts of copper, zinc, and iron. These requirements are characteristic of all yeasts. The vitamin requirements, however, differ among species. Eor laboratory and many industrial cultures, a commercial yeast extract contains all the required nutrients (see also Mineral nutrients). 

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