METHOD FOR DETERMINATION OF WEIGHT PERCENTAGE OF PECTIN SUBSTANCES FRACTION IN VEGETAL OBJECTS BY WAY OF CONDUCTOMETRIC TITRATION Russian patent published in 2013 - IPC A23L1/524 C08B37/06 G01N27/06 

FIELD: food industry.

SUBSTANCE: invention relates to technical biochemistry, in particular - to determination of pectin substances quantity in vegetal raw material. "Standardised" solutions of pectin substances fractions are prepared. The fractions solutions are sampled. Saponification of pectin substances fractions in the samples of the solutions being analysed is performed with 2.5 ml of 40% NaOH solution. The pectin substances fractions are sedimented with 2.5 ml of concentrated HCl. The solutions being analysed are centrifuged in 50 ml test tubes, rotation frequency being no less than 500 rpm, during 5-7 minutes. The sediments of pectin substances fractions are suspended in distilled water in a titration cup on a magnetic stirrer for at least 30 minutes. One performs conductometric titration of the suspension of pectin substances fractions sediment, stirring. Following the conductometric titration results, graphs are drawn, relying whereon one identifies the volume of the titrant spent on pectin acid titration. Pectin substances fractions weight percentage is calculated from the formula: $$\omega =\frac{176\times \mathrm{0,2}\times V}{10\times 200}\times \mathrm{100,}$$ where 176 - pectin acid equivalent; 0.2 - titrant normality; V - titrant volume spent on pectin acid titration, ml; 200 - volume of the solution of the corresponding pectin substances fraction taken for analysis, ml; 10 - conversion to acid milliequivalents (1 ml of 0.1n NaOH corresponding to 0.1 acid milliequivalent); 100 - percentage conversion factor.

EFFECT: invention enables obtainment of accurate data with high coincidence of parallel analyses and ensures labour and time expenditures saving at all the process stages.

6 dwg, 1 ex