Effect of Acid and Heat on Dextrose and Dextrose Polymers

Abstract

acid hydrolysis of starch has been used for over a century for the production of starch sirups and dextrose and as an analytical procedure for the determination of starch. This longcontinued use of the procedure would normally indicate wellestablished principles for the acid hydrolysis of starch. However, an examination of the literature on this subject indicates that the basic underlying conditions of hydrolysis are still not too well understood. The lack of clarity in published research may arise from two causes:The commercial hydrolysis of starch employs relatively high concentrations of starch and very low concentrations of acid in proportion to the starch.Published research on the reversion, polymerization, or condensation of dextrose by acid has employed high concentrations of acid in proportion to the dextrose so treated.The condensation polymerization of dextrose in more concentrated solutions under the influence of heat and small amounts of acid has received relatively little attention. This paper reports research on hydrolysis employing the usual variables of time, temperature, and acid concentration, more particularly the pH, but it is devoted chiefly to a study of the most neglected variable, carbohydrate concentration of the system, or the sugarwater ratio. This variable is shown to be more significant than any of the others on the final reducing sugar content. COMMERCIAL HYDROLYSIS OF STARCH

Kinetic modeling analysis of maleic acid‐catalyzed hemicellulose hydrolysis in corn stover

“…Moreover, when 50 g/L initial xylose concentration was applied, the firstorder treatment resulted in very poor linear correlation (R 2 -values around 0.56). The HPLC analysis of the reaction products showed a significant amount of xylose dimers formed by a second reaction, as has been noted previously (Fetzer et al, 1953). Since the dimerization reaction is a function of xylose concentration (higher than first-order kinetics), more sophisticated kinetics that include both reactions should be used to model xylose loss at higher xylose concentrations.…”

Cellulose: Biosynthesis and Structure

“…These cells are most often at the gamete or zoospore stage [9]. These cells are most often at the gamete or zoospore stage [9].…”

“…The coefficients of diffusion and sedimentation atinfinite-dilution Do and So presented in Table 11 2), NCC according to papers [83], [84] (3) Table 11.10: 1-1(1); 2-1(4); 3-2(4); 4-1(5); 5-1(6); 6-2(10); 7-1(8); 8-2(11); 9-2(13); 10-1 (9) and The equations obtained correlate with similar dependences for NCC samples with close nitrogen content [83], [84]. The high values of the exponent in Eqs.…”

“…Curve 3 in Fig. The basic reason of this seems to be polydispersity in the molecular weight which is not considered by (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) of nitrocellulose in cyclohexanone the Noda-Hearst theory. The general character of experimental dependence corresponds to curve 3, with a 20-fold increase of molecular weight, the G-value decreases by 2.7 times.…”

“…It should be stressed that the limited solubility of cellulose nitrate (it is related to cellulose itself to an even greater extent) makes it difficult to investigate the flow birefringence with a wide variation of the solvent refraction index, ns and thus set limits of application of the microconfiguration effect for quantitative estimation of the inherent anisotropy and rigidity of the molecular chain. Plots of (x/g)-values as a function of solution concentration C of various nitrocellulose fractions (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14) in cyclohexanone 11.50.…”