Food components fiber

Fluorescence microspectrophotometry typically provides chemical information in three modes spectral characterization, constituent mapping in specimens, and kinetic measurements of enzyme systems or photobleaching. All three approaches assist in defining chemical composition and properties in situ and one or all may be incorporated into modem instruments. Software control of monochrometers allows precise analysis of absoiption and/or fluorescence emission characteristics in foods, and routine detailed spectral analysis of large numbers of food elements (e.g., cells, fibers, fat droplets, protein bodies, crystals, etc.) is accomplished easily. The limit to the number of applications is really only that which is imposed by the imagination - there are quite incredible numbers of reagents which are capable of selective fluorescence tagging of food components, and their application is as diverse as the variety of problems in the research laboratory. 

Although there are a number of important food components which are naturally fluorescent (e.g., cereal brans, lignified materials such as pea, soy and cotton fiber, and even proteins and pigments), detection of many food components requires application of specific fluorochromes or diachromes. Therefore, quantitative analysis using microscopic imaging also requires judicious use of sensitive dyes or stains suitable for visualization and rapid measurement. The dyes must be stable, non-toxic to liing cells, easily and inexpensively... 

While absorption and concentration in blood and urine appear to be closely correlated under these conditions, a number of factors such as food or specific food components (let fiber, protein or minerals) and history of zinc nutrlture may affect plasma or urinary levels, especially in individual samples taken at specific times after Ingestion. Changes In zinc levels In idiole blood, plasma or serum over time are the result of several competing processes as Illustrated in Figure 1. These include ... 

A recent survey of consumer attitudes and viewpoints found that the majority of U.S. consumers believe that natural substances in food can play a role in disease prevention (104). The designer foods movement to modify food components is broad and promotes increased uses of natural source phytochemicals bioflavonoids fiber, calcium, and/or vitamin-enriched milks and cereal products probiotic yogurt, and isotonic beverages in addition to meat and eggs (105). 

As a byproduct of the juice concentrate industry, an estimated 500,000 to 1,000,000 tons of wet pulp are produced each crop year. Unlike suggested more exotic sources of dietary fiber, orange pulp is already an established, commonly consumed food component in the American diet. The functional and nutrient properties of washed orange pulp are intimately related to a series of factors. The foremost of these is the orange species but also significant are climatic and crop year variants, harvest maturity, expression and extraction processing variables, uncontrolled enzymatic and microbial activity as well as method of drying. Because of variations in the material, application and development as a fiber has been limited. 

This broad understanding of dietary fiber makes it difficult to describe or characterize chemically and to elucidate its behavior in the gastrointestinal tract. Nevertheless with changing dietary habits and recommendations for food intake for good health and nutrition, it is important that the chemistry of this class of food components be more readily characterized and understood. Since much dietary fiber Is of cell wall origin, some of the approaches that have been successfully used to define and explain the chemistry of plant cell walls (5, 6) should be applicable to research on the characterization and function of dietary fiber (7, 9), To this end we have... 

Additional experiments are needed to relate not only the monosaccharide composition of the fibers fed to fecal output but also the structures of those fibers and how they may have been modified In the digestive tract even If not fermented. The effect of fiber particle size and pretreatment should be studied. Free sugar, starch, cellulose and uronlc acid measurements should be made in order to obtain a more complete picture of what survives and what is metabolized. The effect of dietary fibers on the digestion and utilization of other polysaccharides and other food components should be studied. This Information, together with fermentation data. Including gas and VFA production, will provide a better understanding of the role and value of different dietary fibers and their effects on nutrient bloavallablllty. 

It is my hope and belief that this publication will help in the expansion and utilization of fiber sources in foods, as well as in pharmaceutical and medical preparations. After all, we should recognize that the chance to accomplish this is quite favorable because complex carbohydrates, which are the main constituents of dietary fiber, represent the only group of major food components for which increased daily intake is repeatedly being recommended. 

Crude fiber Crude fiber analysis is a measure of food components that are indigestible and is determined as material insoluble in dilute acid and dilute alkali under standard conditions. The basic method involves the defatted sample being boiled, first in 1.25% H2SO4 and then in 1.25% NaOH, with the residue being filtered, dried, weighed, incinerated, and reweighed. The loss in weight on incineration is taken as the crude fiber content. 

Polarizing microscopy is used to examine food components that exhibit birefringence (an ordered crystalline structure). Many food components are birefringent, e.g., starch, plant cell walls, specialized stone cells in some plant tissues, muscle fibers, fats from both plant and animal sources, and different types of flavor and seasoning components. 

Redgwell RJ, Fischer M. Dietary fiber as a versatile food component an industrial perspective. Mol Nutr Food Res. 2005 49 521-535. 

Appiications battery separator, faucet components, fibers, hot water fittings, medical applications which require resistance to hot water and sterilization, membranes (hemodialysis, water treatment, bioprocessing, food and beverage, and gas separation), microwave cookware, plumbing manifolds, printed circuit boards, tubing, solar hot water applications, utrafiltration membrane ... 

Molecular Interactions. Various polysaccharides readily associate with other substances, including bile acids and cholesterol, proteins, small organic molecules, inorganic salts, and ions. Anionic polysaccharides form salts and chelate complexes with cations some neutral polysaccharides form complexes with inorganic salts and some interactions are stmcture specific. Starch amylose and the linear branches of amylopectin form inclusion complexes with several classes of polar molecules, including fatty acids, glycerides, alcohols, esters, ketones, and iodine/iodide. The absorbed molecule occupies the cavity of the amylose helix, which has the capacity to expand somewhat to accommodate larger molecules. The starch—Hpid complex is important in food systems. Whether similar inclusion complexes can form with any of the dietary fiber components is not known. 

Dietary fiber and fiber-rich food fractions bind bile acids and bile salts in vitro. This interaction is more pronounced for the lignin component. 

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