Sucrose: A nonreducing disaccharide composed of GLUCOSE and FRUCTOSE linked via their anomeric carbons. It is obtained commercially from SUGARCANE, sugar beet (BETA VULGARIS), and other plants and used extensively as a food and a sweetener.Dietary Sucrose: Sucrose present in the diet. It is added to food and drinks as a sweetener.Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Sweetening Agents: Substances that sweeten food, beverages, medications, etc., such as sugar, saccharine or other low-calorie synthetic products. (From Random House Unabridged Dictionary, 2d ed)beta-Fructofuranosidase: A glycoside hydrolase found primarily in PLANTS and YEASTS. It has specificity for beta-D-fructofuranosides such as SUCROSE.Glucosyltransferases: Enzymes that catalyze the transfer of glucose from a nucleoside diphosphate glucose to an acceptor molecule which is frequently another carbohydrate. EC 2.4.1.-.Taste: The ability to detect chemicals through gustatory receptors in the mouth, including those on the TONGUE; the PALATE; the PHARYNX; and the EPIGLOTTIS.Fructose: A monosaccharide in sweet fruits and honey that is soluble in water, alcohol, or ether. It is used as a preservative and an intravenous infusion in parenteral feeding.Starch: Any of a group of polysaccharides of the general formula (C6-H10-O5)n, composed of a long-chain polymer of glucose in the form of amylose and amylopectin. It is the chief storage form of energy reserve (carbohydrates) in plants.Isomaltose: A disaccharide consisting of two glucose units in an alpha (1-6) glycosidic linkage.Carbohydrate Metabolism: Cellular processes in biosynthesis (anabolism) and degradation (catabolism) of CARBOHYDRATES.Fructans: Polysaccharides composed of D-fructose units.Food Preferences: The selection of one food over another.SucraseDietary Carbohydrates: Carbohydrates present in food comprising digestible sugars and starches and indigestible cellulose and other dietary fibers. The former are the major source of energy. The sugars are in beet and cane sugar, fruits, honey, sweet corn, corn syrup, milk and milk products, etc.; the starches are in cereal grains, legumes (FABACEAE), tubers, etc. (From Claudio & Lagua, Nutrition and Diet Therapy Dictionary, 3d ed, p32, p277)Cell Fractionation: Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.Glucaric Acid: A sugar acid derived from D-glucose in which both the aldehydic carbon atom and the carbon atom bearing the primary hydroxyl group are oxidized to carboxylic acid groups.Cariogenic Agents: Substances that promote DENTAL CARIES.Streptococcus mutans: A polysaccharide-producing species of STREPTOCOCCUS isolated from human dental plaque.Maltose: A dextrodisaccharide from malt and starch. It is used as a sweetening agent and fermentable intermediate in brewing. (Grant & Hackh's Chemical Dictionary, 5th ed)Phloem: Plant tissue that carries nutrients, especially sucrose, by turgor pressure. Movement is bidirectional, in contrast to XYLEM where it is only upward. Phloem originates and grows outwards from meristematic cells (MERISTEM) in the vascular cambium. P-proteins, a type of LECTINS, are characteristically found in phloem.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.Molecular Weight: The sum of the weight of all the atoms in a molecule.Kinetics: The rate dynamics in chemical or physical systems.Raffinose: A trisaccharide occurring in Australian manna (from Eucalyptus spp, Myrtaceae) and in cottonseed meal.Fructokinases: A class of enzymes that catalyzes the phosphorylation of fructose in the presence of ATP. EC 2.7.1.-.Glycoside HydrolasesSodium Chloride: A ubiquitous sodium salt that is commonly used to season food.TrehaloseHypertonic Solutions: Solutions that have a greater osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.Taste Threshold: The minimum concentration at which taste sensitivity to a particular substance or food can be perceived.Glucose: A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Quinine: An alkaloid derived from the bark of the cinchona tree. It is used as an antimalarial drug, and is the active ingredient in extracts of the cinchona that have been used for that purpose since before 1633. Quinine is also a mild antipyretic and analgesic and has been used in common cold preparations for that purpose. It was used commonly and as a bitter and flavoring agent, and is still useful for the treatment of babesiosis. Quinine is also useful in some muscular disorders, especially nocturnal leg cramps and myotonia congenita, because of its direct effects on muscle membrane and sodium channels. The mechanisms of its antimalarial effects are not well understood.Taste Perception: The process by which the nature and meaning of gustatory stimuli are recognized and interpreted by the brain. The four basic classes of taste perception are salty, sweet, bitter, and sour.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Saccharin: Flavoring agent and non-nutritive sweetener.Carbohydrates: The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.Aspartame: Flavoring agent sweeter than sugar, metabolized as PHENYLALANINE and ASPARTIC ACID.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Cryoprotective Agents: Substances that provide protection against the harmful effects of freezing temperatures.Disaccharides: Oligosaccharides containing two monosaccharide units linked by a glycosidic bond.Plant Leaves: Expanded structures, usually green, of vascular plants, characteristically consisting of a bladelike expansion attached to a stem, and functioning as the principal organ of photosynthesis and transpiration. (American Heritage Dictionary, 2d ed)Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Osmosis: Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Saccharum: A plant genus of the family POACEAE widely cultivated in the tropics for the sweet cane that is processed into sugar.Gene Expression Regulation, Plant: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.Uridine Diphosphate Glucose: A key intermediate in carbohydrate metabolism. Serves as a precursor of glycogen, can be metabolized into UDPgalactose and UDPglucuronic acid which can then be incorporated into polysaccharides as galactose and glucuronic acid. Also serves as a precursor of sucrose lipopolysaccharides, and glycosphingolipids.DextranaseConditioning, Operant: Learning situations in which the sequence responses of the subject are instrumental in producing reinforcement. When the correct response occurs, which involves the selection from among a repertoire of responses, the subject is immediately reinforced.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Osmolar Concentration: The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.Glucans: Polysaccharides composed of repeating glucose units. They can consist of branched or unbranched chains in any linkages.TritiumWater: A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Membrane Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Feeding Behavior: Behavioral responses or sequences associated with eating including modes of feeding, rhythmic patterns of eating, and time intervals.Subcellular Fractions: Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)Osmotic Pressure: The pressure required to prevent the passage of solvent through a semipermeable membrane that separates a pure solvent from a solution of the solvent and solute or that separates different concentrations of a solution. It is proportional to the osmolality of the solution.Carbon Isotopes: Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.