Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Starch defined

Resistant starch Defined as the sum of starch and products of starch degradation not absorbed in the small intestine by healthy individuals. Resistant starches not digested in the small intestine reach the colon, where they are readily fermented by naturally occurring microflora. One of the main acids produced by these microorganisms is butyric acid, which is believed to play a positive role in promoting colon health. Resistant starch is classified into four categories. [Pg.697]

Oligo- and higher saccharides are produced extensively by acid-and/or enzyme-catalyzed hydrolysis of starch, generally in the form of symps of mixtures (12). These products are classified by thek dextrose equivalency (DE), which is an indication of thek molecular size and is a measure of thek reducing power with the DE value of anhydrous D-glucose defined as 100. [Pg.483]

Fermentation occurs naturally in various microorganisms such as bacteria, yeasts, fungi and in mammalian muscle. Yeasts were discovered to have connection with fermentation as observed by Louis Pasteur and originally defined as respiration without air. However, it does not have to always occur in anaerobic condition. For example, starch when fermented under... [Pg.46]

The diastase activity was traditionally determined according to the Schade method in the earlier years (Schade et al., 1958). One unit of diastase activity (or more specifically, a-amylase), DN, is defined as that amoimt of enz)nne that converts 0.01 g of starch to the prescribed endpoint in 1 h at 37 °C under the experimental conditions. In this assay, a standard solution of starch, which reacts with iodine to produce a color solution, is used as a substrate for honey enzymes under the standard conditions (Rendleman, 2003). A recently developed procedure uses an insoluble, dyed starch substrate (Persano Oddo and Pulcini, 1999). As this substrate is hydrolyzed by ot-amylase, soluble dyed starch fragments are released into solution. After reaction termination and insoluble substrate removal by centrifugation, absorbance of the supernatant solution (at 620 nm) is measured. The absorbance is proportional to the diastase activity. This procedure has been widely adopted in the honey industry due to the convenience of a commercially available substrate and the simple assay format. [Pg.106]

Growth can be defined as the production of organic matter by increase in size or volume. This process involves the uptake of water, carbon dioxide and minerals. In plants, growth is made possible by the process of photosynthesis, which produces the sugars (as primary components) from which compounds such as starch, cellulose, amino acids and proteins are derived. [Pg.57]

Dietary Fibre. An area of some contention is what should be included as dietary fibre. There are several different methods of measuring dietary fibre and all of them will give different results on the same sample. The EU favours the Association of Analytical Chemists (AOAC) method, which includes lignin and resistant starch, while the UK has preferred the Englyst method and has defined fibre as nonstarch polysaccharides from cell walls as the only substances that count as fibre. [Pg.49]

It was soon realized (J10, R5) that Hp did not consist of a single protein, but of a group of proteins with very similar properties. Conclusive evidence of the molecular heterogeneity of Hp was produced by Smithies (S5), who used electrophoresis with a defined starch gel in which the mobility of protein molecules varies with their charge and size (Fig. 1). Smithies and Walkers discovery (S9) of different types of... [Pg.151]

Amphiphile-oil-water system, temperature of, 16 424-426 Amphiphiles, 16 420 Amphiphile strength, 6 424 Amphiphilic chemicals, 17 56 Amphiphilic copolymers, 20 482 behavior of, 20 483 well-defined, 20 485-490 Amphiphilic molecules, 15 99-101 Amphiphilic plasticizers, 14 480 Amphiphilic polymer blend, 23 720 Amphiphilic polymers statistical, 20 484-490 stimuli-responsive, 20 482-483 Ampholytes, 9 746-747 Amphoteric cyclocopolymers, water-soluble, 23 721 Amphoteric starches, 4 722 Amphoteric (zwitterionic) surfactants, 24 148... [Pg.53]

Indicates additive discussed in this chapter. Other additives discussed in this chapter but not defined above are adjuvants, foam stabilizers and foaming agents. These are described in Table 11.2. For historical reasons Modified starch is an exceptional category, because all the other categories are functional uses, whereas modified starches are a group of substances. [Pg.251]

Starch annealing involves heating starches with sufficient hydration below their Tq to facilitate molecular mobility (Tester et ah, 2001). Annealing is defined as "a physical treatment that involves incubation of starch granules in excess (>60% w/w) or at intermediate (40-55% w/w) water content during a certain period of time at a temperature above the glass... [Pg.253]

Dietary fibre was defined by Hugh TroweU as the plant polysaccharides and lignin which are resistant to hydrolysis by the digestive enzymes of humans . This definition lacks chemical precision, because non-flbrous pectins and gums are also present. The term nonstarch polysaccharide (NSP) is often preferred, although the term dietary fibre still persists. Unfortunately, NSP is also not satisfactory since some starch, known as resistant or par-... [Pg.73]

CGTase Activity Assay. Aaivity was measured by the Pharmacia Phadebas Amylase Assay at pH 6.0, 60 C in O.IM sodium acetate (100 ppm Ca+ " ) for 15 minutes using B, stearothermophilus alpha-amylase as a standard. Alpha-amylase preparations were assayed under the same conditions. One Phadebas unit is defined as the amount of enzyme that will catalyze the hydrolysis of 1.0 micromole of glucosidic linkages of Lintner starch per minute at 6OOC, pH 6.0. [Pg.386]

A specialty starch is defined as one where some form of chemical modification takes place to give properties to the starch that are lacking in the native product. The remainder of this paper will discuss the chemistry of modification and the chemical and physical reasons for the use of specialty starches in treating paper. [Pg.275]

Primary axillary hyperhidrosis (Botox only) The recommended dose is 50 units per axilla. Define the hyperhidrotic area to be injected using standard staining techniques (eg. Minor s Iodine-Starch Test). Botulinum toxin type A is reconstituted with 0.9% nonpreserved sterile saline (100 units/4 mL). Using a 30-gauge needle, 50 units of botulinum toxin type A (2 mL) is injected intradermally in 0.1 to 0.2 mL aliquots to each axilla evenly distributed in multiple sites (10 to 15) approximately 1 to 2 cm apart. [Pg.1340]

Some naturally occurring polymers such as cellulose, starch, wool, and silk are classified as condensation polymers, since one can postulate their synthesis from certain hypothetical reactants by the elimination of water. Thus cellulose can he thought of as the polyether formed by the dehydration of glucose. Carothers included such polymers by defining condensation polymers as those in which the formula of the repeating unit lacks certain atoms that are present in the monomer(s) from which it is formed or to which it may be degraded. In this... [Pg.2]

To determine the amylose content of starch, the iodine reaction has been most commonly used because amylose and amylopectin have different abilities to bind iodine. The methods such as blue value (absorbance at 680 nm for starch-iodine complex using amylose and amylopectin standards), and potentiometric and amperometric titration have been used for more than 50 years. These procedures are based on the capacity of amylose to form helical inclusion complexes with iodine, which display a blue color characterized by a maximum absorption wavelength (kmax) above 620 nm. During the titration of starch with iodine solution, the amount (mg) of iodine bound to 100 mg of starch is determined. The value is defined as iodine-binding capacity or iodine affinity (lA). The amylose content is based on the iodine affinity of starch vs. purified linear fraction from the standard 100 mg pure linear amylose fraction has an iodine affinity of 19.5-21.0mg depending on amylose source. Amylopectin binds 0-1.2mg iodine per 100mg (Banks and Greenwood, 1975). The amylose content determined by potentiometric titration is considered an absolute amylose content if the sample is defatted before analysis. [Pg.230]


See other pages where Starch defined is mentioned: [Pg.624]    [Pg.180]    [Pg.302]    [Pg.294]    [Pg.407]    [Pg.483]    [Pg.527]    [Pg.1023]    [Pg.17]    [Pg.226]    [Pg.624]    [Pg.180]    [Pg.284]    [Pg.137]    [Pg.65]    [Pg.67]    [Pg.70]    [Pg.485]    [Pg.112]    [Pg.143]    [Pg.160]    [Pg.20]    [Pg.144]    [Pg.766]    [Pg.234]    [Pg.53]    [Pg.66]    [Pg.66]    [Pg.34]    [Pg.232]    [Pg.191]    [Pg.243]    [Pg.244]    [Pg.281]   
See also in sourсe #XX -- [ Pg.605 ]




SEARCH



© 2024 chempedia.info