METHOD FOR DETERMINATION OF AMIDATED PECTIN WEIGHT FRACTION IN MARMALADE Russian patent published in 2014 - IPC G01N33/02 

FIELD: food industry.

SUBSTANCE: for determination of amidated pectin weight fraction in marmalade one prepares gauging solutions. For this purpose amidated pectin in an amount of 0.25 g, 0.50 g, 0.75g, 1.25 g (respectively) is placed into flasks. Then one adds distilled water in an amount of 10 cm³ in each flask. One heats the flasks in a water bath until complete dissolution of amidated pectin. Then the solution mass is diluted to 25 g with distilled water. The gauging solutions are alternatively placed into the frustrated total internal reflection pan of an IR spectrophotometer. The spectre is registered; the solution absorption is measured with frequencies equal to 1644, 1640 and 1637 cm^-1. One calculates the absorption peak height A for the wave number equal to 1640 cm^-1 (optic density units) from the formula $$A=A_0-\frac{A_1+A_2}{2}\text{ (1) }$$ (1), where A_0, A_1, A₂ - the solution absorption with the frequency equal to 1640 cm^-1, 1644 cm^-1, 1637 cm^-1, optic density units, respectively. One draws a gauging graph. Then marmalade in an amount of 12.5 g is weighed. One adds distilled water in an amount of 10 cm³ in the flask. One performs heating in a water bath. The produced solution is diluted to 25 g with distilled water. One performs placement into the pan, registration of the spectre and measurement of the absorption peak height for the wave number equal to 1640 cm^-1. From the gauging graph, one identifies the weight fraction of amidated pectin. Amidated pectin weight fraction (M) is calculated according to the formula: M=0.44·T·2 (2), where 0.44 - coefficient accounting for influence of organic acids contained in the product; T - amidated pectin weight fraction in the solution under study, %; 2 - coefficient accounting for the sample dilution.

EFFECT: invention ensures determination of amidated pectin weight fraction according to the IR-spectre of amido groups in marmalade what allows to control marmalade quality.

1 dwg, 1 ex