Dyed starches

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. 

Amylase Two-point rate 10 540 Dyed starch and dyed saccharides... 

Since the diameter of the dye molecule is greater than that of the amylose helix (13 A) and the distance (8 A) between adjacent spirals of the helix, the chromo-genic groups of the dyed starch are assumed to be located on the exterior of the helix. 

Nonabsorbable Natural Sutures. Cotton and silk are the only nonabsorbable sutures made from natural fibers that are stiH available ia the United States. Cotton suture is made from fibers harvested from various species of plants belonging to the genus Gossipium. The fiber is composed principally of ceUulose. The seeds are separated from the cotton boUs, which are carded, combed, and spun iato yams that are then braided or twisted to form sutures ia a range of sizes (Table 4). The suture is bleached with hydrogen peroxide and subsequendy coated (finished or glaced) with starch and wax. The suture may be white or dyed blue with D C Blue No. 9. 

In the late 1960 s a new series of methods was introduced for the determination of amylase, involving the use of a starch-dye complex. Dyes such as Renazol brilliant blue (68) Reactive Red 2B (69) (used in the substrate Dy-Amyl, General Diagnostic Division, Warner-Chilcott Laboratories), Cibachrom Blue (70)... 

Technical Tests.—To ascertain the suitability of a starch for use in the dressing of textiles, samples of fabrics dyed with sensitive colours (benzopurpurin, Turkey red, logwood black) or of bleached fabrics are treated with the starch the dry materials are examined as regards feel and change of colour, while the general appearance is compared with that of the same material dressed with a standard starch. 

Robinson, Stuart (1968). A History of Dyed Textiles Dyes, Fibres, Painted Bark, Batik, Starch-Resist, Discharge, Tie-Dye, Further Sources for Research. Cambridge, MA MIT Press. 

Inouchi ND, Glover DY Takaya T, Fuwa H. Starch/Starke. 1983 35 371. 

Inouchi N, Glover Dy Sugimoto Y, Fuwa H. Starch/Stdrke. 1984 36 8. 

Fuwa H, Glover Dy Miyaura K, Inouchi N, Konishi Y, Sugimoto Y. Starch/Stdrke. 1987 39 295. 

A. intact starch granules B, swollen starch granules b, blue d, dark g, green I, light li, lilac p, pink r, red v, violet w, white y, yellow , partly dyed —no dye accepted. 

Starches can be chemically dyed by reacting a procion dye with 2,4,6-trichloro-triazine or 2,4-dichloro-triazine, followed by reaction with alkaline starch [170,171]. A chloro group on the triazine ring of the dye derivative is replaced by a starch hydroxyl group to form a stable... 

When making very dehcate materials it may be necessary to use a yam which is so fine that it would break down under the stresses imposed on it during manufacture. The strength, however, is sufficient once the fabric is made because of the mutual support of adjacent threads. In such cases it is customary to impart temporary strength to the yam by a process known as sizing. This consists of impregnating the thread with some easily removed substance such as starch or dextrine and, in the case of the more modern man-made fibres, with a synthetic product such as polyvinyl alcohol or polyacrylic acid. The size is usually removed before the article is dyed or bleached. Yarns are frequently referred to as warp or weft yarns. In a... 

Sulphur dyes cannot be applied to protein fibres by normal methods on account of the strongly alkaline nature of the dye liquors. Wool is never dyed with these dyestuffs, but a reasonably fast black was obtained on wool and cotton unions by adding 5 per cent on the weight of the goods of a protective colloid such as glue or boiled starch. 

Obtain 1 mL of chlorine water from the reagent bench. Test its effect on blue litmus paper, starch-potassium iodide paper, and dyed cotton cloth (Laboratory Methods P), and describe your results in TABLE 39.1A1. Add 10. drops of cyclohexane to the chlorine water contained in a test tube, stopper the test tube with a cork, shake the contents, and then let the contents stand a few moments. Describe what you observe in TABLE 39.1A1. 

Place about 0.5 g of manganese dioxide, Mn02, weighed on a beam balance, in a 16 X 150-mm test tube, and add 5 mL of the HCl solution. Warm the test tube gently in a water bath. Describe the color of the evolved gas in TABLE 39.1B2. Test the effect of the evolved gas on moist starch-potassium iodide paper and moist dyed cotton cloth placed in the concave dip of a watch glass and inverted over the mouth of the test tube. Describe in TABLE 39.1B2 what you observe. 

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