Starch Acetate Research Articles

Chronic (89-week) feeding study with hydroxypropyl distarch phosphate, starch acetate, lactose and sodium alginate in mice

A chronic feeding study was carried out in mice with two chemically modified potato starches, hydroxypropyl distarch phosphate (HP-starch) and starch acetate (AC-starch), and with lactose and sodium alginate. Each of the materials was fed to a group of 75 male and 75 female mice for 89 wk. The dietary level of the test products was gradually increased until the diets contained (by weight) 55% HP-starch, 55% AC-starch, 55% lactose or 25% alginate. The control diet contained 55% pregelatinized potato starch. Each of the four test materials caused increased water consumption, distinct caecal and colonic enlargement, a slightly increased incidence of intratubular nephrosis and, with the exception of AC-starch, also slightly lower body weights. An increased incidence of gastric trichobezoars was observed in mice fed either the modified starches or lactose. The occurrence of concrements in the renal pelvis along with slight urinary changes, such as increased amounts of amorphous material in the urine and increased urinary Ca content, in mice fed HP-starch, AC-starch or lactose was regarded as an effect of little, if any, toxicological significance. Alginate fed at 25% (w/w) of the diet was nephrotoxic to mice, as shown by extremely high water consumption, high urine production, urinary incontinence, high pH and low specific gravity of the urine, increased level of blood urea nitrogen, increased kidney weights, distension of the renal calyx and the high incidence of dilated distal tubules. Caecal and colonic enlargement and changes in urinalysis were found to be reversible and had completely or largely disappeared within 2–5 wk of the cessation of the treatment in wk 87. The incidence of intratubular calcinosis or of concrements in the pelvic space was not reduced during the recovery period. The study did not provide any evidence of carcinogenicity of the products tested.

Shear Stress Relaxation of Native and Modified Potato Starch Gels

AbstractShear stress relaxation measurements were used to characterize native potato starch gels, and modified gels, such as starch acetate, distarch phosphate, dihydroxypropyl distarch phosphate and lipid coated starch. It was found that cross‐linking and lipid coating greatly increased the stiffness of the gels, which was observed as increased relaxation modulus (G). These gels behaved like viscoelastic solids, which was observed as increased relaxation times (T½) and increased apparent residual moduls (G∞). During ageing, an increase in G and T½ as well as in G∞ was observed for the native starch, the starch acetate and the distarch phosphate. The hydroxypropoyl distarch phosphate and the lipid coated starch were very stable during ageing. To interpret the results in terms of the structure of the starch gel, the gel was described as a composite material, and the stress relaxation results were discussed according to a cooperative theory of flow.

Xylanase activity of an endo-cellulase of carboxymethyl-cellulase type from Irpex lacteus (Polyporus tulipiferae).

An endo-cellulase [EC 3.2.1.4.] of carboxymethyl-cellulase type (F-1) which was fractionated from culture filtrate of Irpex lacetus and purified to electrophoretic and ultracentrifugal homogeneity, was found to show xylanase [EC 3.2.1.8.] activity. The activity was not removed from any of the intermediate fractions during the purification of the initial F-I peak, and the radio of xylanase to cellulase activity remained almost unchanged through the purification processes. The xylanase activity of F-I showed not only the same optiomal pH, heat stability, and pH stability as its cellulase activity, but also the same mobility as the cellulase activity upon cellulose acetate film and starch zone electrophoreses. The overall rates of hydrolysis of mixtures of variouis concentrations of CM-cellulose and xylan by F-1 coincided well with those calculated from the Michaelis-Menten treatment of two substances competing for the same active site of the enzyme. These results indicate that the xylanase activity of F-1 is intrinsic to the cellulase itself.

Two-year feeding and multigeneration studies in rats on five chemically modified starches

Five chemically modified starches, acetylated distarch phosphate, acetylated diamylopectin phosphate, starch acetate, hydroxypropyl distarch glycerol and phosphated distarch phosphate, were fed to rats at dietary levels of 0 (control), 5, 10 and 30% for 2 yr and at one level, 10%, over three generations. In the 2-yr study, no adverse effects were observed on mortality, food intake, haematology, blood biochemistry or urine composition. Each of the modified starches examined, except the phosphated distarch phosphate, slightly reduced body weights at the 30% level and caused distinct caecal enlargement at 10 and 30%, but the microscopic structure of the caecal wall was normal. In comparison with the controls, the males fed the 30% level of any of the modified starches showed a slightly increased degree and incidence of focal hyperplasia of the renal papillary and pelvic epithelium, accompanied by calcified patches in the underlying tissue. The studies did not provide any indication of carcinogenicity. The multigeneration study showed no effect on fertility, on lactation performance or on embryonic or pre-weaning mortality. Extensive microscopic examination of the F3b-generation rats failed to reveal any changes attributable to treatment. It was concluded that the feeding of each of the modified starches at dietary levels up to 30% for 2 yr and at a level of 10% over three generations did not result in any distinct effect of toxicological significance.

Beobachtungen über die Viskositätseigenschaften niedrig substituierter Stärkeacetate

AbstractObservations on Viscosity Properties of Low‐Substituted Starch Acetates. It was shown that with low‐substituted starches dispersibility in water increases with increasing content of acetyl groups and increasing temperature. This fact becomes evident in lower temperatures at the beginning of pasting and at maximum of „viscosity”︁‐graph. This has confirmed and extended earlier observations. Viscosity of starch acetate pastes is lower in cold as well as in hot state as that of native starch paste. Viscosity decreases down to an acetyl content of 2.36% and it changes only unnoticeably above that point. The decreasing gel forming ability can be expressed by the ratio of paste viscosities in cold and hot state.The rotation viscosimeter Rheotest proved well applicable for studies of viscosity and rheological properties of starch and of low‐substituted acetates.

Polysaccharide-gelatin complexes in acidified ethanol solutions

Numerous polysaccharides of diverse monomeric constituents and modes of linkage (such as galactan, isolichenan, laminaran, levans, lichenan, pullulan, and yeast mannan) combine with gelatin to form macromolecular complexes soluble in 0.83% trichloroacetic acid −83% ethanol. In contrast, inulin, nigeran, and yeast d-glucan do not complex with gelatin. Dextrans having various contents of α- d-(1→6), α- d-(1→4), and α- d-(1→3) linkages appear to bind gelatin more effectively than either glycogen or soluble starch. Decreased stoichiometric binding has been correlated with increased branching of the dextran polymers; conversely, the branched-chain levans bind gelatin, whereas inulin, a linear polymer, does not. With the exception of starch acetate, esterification of neutral glycans with formic, acetic, or phosphoric acid either enhances, or has no effect on, formation of complex.

THE LOCATION OF XANTHATE GROUPS IN PARTIALLY SUBSTITUTED STARCH XANTHATES

The rate of xanthation of starch with carbon disulphide in 17.8% potassium hydroxide at 23° was followed by converting the potassium salts to the S-methyl xanthate esters, and analyzing the latter for sulphur. These esters were tritylated without changing the xanthate D.S., and unity minus the trityl D.S. was assumed to represent xanthate D.S. in the primary alcohol positions of the starch. About 62% of the xanthate groups occupied secondary positions after 100 minutes of xanthation, but after 3350 minutes about 58% of the surviving xanthate groups were primary.A sodium chlorite–pyridine–lactic acid mixture reduced the sulphur content of a fully acetylated starch S-methyl xanthate by about nine-tenths with little loss of acetyl groups, but the residual sulphur could not be eliminated and the resulting starch acetate could not be completely reacetylated or tosylated. The location of the hydroxyl groups in this acetate thus could not be studied by the tosylation–iodination method.

Enteric Coatings III : An Improved Enteric Coating and Its In Vitro Evaluation

A new, improved enteric coating, prepared from styrene-maleic acid copolymer, dibutyl phthalate, and talc (I) was compared with previously reported coatings containing starch acetate phthalate, dibutyl phthalate, and talc (II), and cellulose acetate phthalate, propylene glycol, talc, and sorbitan monooleate (III). Increasing the amount of talc applied per tablet increases the disintegration time of the coated tablets in artificial intestinal fluid. This effect is least for I, intermediate for II, and greatest for III. A minimum amount of talc is essential to obtain satisfactory acid resistance with I but an increase in the amount of talc does not confer increased acid resistance. The ratio of gastric resistance time : disintegration time in artificial intestinal fluid is greater for I than for II. The ratio of disintegration time in artificial intestinal fluid : weight of enteric coating is much less for I than for either II or III. These observations clearly indicate advantages of I over II and III as enteric coatings. The types of plots presented are useful for comparing one type of coating with another and predicting the properties of the different coatings.

Enteric Coatings II : Starch (and Amylose) Acetate Phthalates

Eight new whole starch (and amylose) acetate phthalates differing in acetyl and phthalyl contents were prepared by acetylation of a reactive form of starch or amylose with acetic anhydride in the presence of formamide followed by phthalylation of the partial acetates with phthalic anhydride in the presence of pyridine. Solubilities of the compounds indicated they would be useful substances for enteric coating. Tablets were enteric coated with one of the starch acetate phthalates and a commercial cellulose acetate phthalate. In vitro , at pH 6.9, ox bile extract but not pancreatin increased the rate of disintegration of the enteric coated tablets; hence, under these conditions, ionization of free carboxyl groups and not the action of enzymes in pancreatin is mainly responsible for the disintegration of these enteric coated tablets.

Preparation and Properties of Starch Acetate

SCHUETZENBERGER ( 15 ) in 1865 reported the preparation of starch acetates by the action of glacial acetic acid, acetic anhydride, or acetyl chloride on starch. The first commercial process for making starch acetates, patented by Cross and Traquair ( 7 ) in 1904, consisted in heating dry starch with less than its weight of glacial acetic acid to produce a water-soluble ester. This product has been marketed under the name of feculose and used in tub-sizing of paper ( 18, 19, 20 ). Recently renewed interest in starch acetate has been evidenced by its manufacture by an American company and by publication of recent research ( 4, 5, 11, 12, 13, 16 ). Water-soluble starch acetates of low acetyl content may be used as filmforming agents in certain flotation processes ( 8 ), in the sizing and coating of textiles and paper, in calico printing, for confectionery fillings and coatings ( 13 ), and as addition agents in baking doughs ( 2 ). Highly acetylated starch has been suggested for ...