Applications

For a variety of reasons, the water content of chocolate is of crucial importance and has to be accurately determined. This poster compares an automated version of the Karl Fischer titration (KFT) using the sequential addition of various solvents with the widespread manual titration at elevated temperatures using a chloroform/methanol mixture. The water contents determined by the two procedures show excellent agreement. However, manual titration requires laborintensive sample preparation, the side reactions are difficult to quantify and hazardous halogenated solvents have to be used. In contrast, automated KFT is straightforward, uses non-hazardous solvents, allows to quantify the side reactions and is easily applicable to water determinations in sugar- and fat-containing matrices.

The photometric determination of nitrate is limited by the fact that the respective methods (salicylic acid, brucine, 2,6-dimethyl phenol, Nesslers reagent after reduction of nitrate to ammonium) are subject to interferences. The direct potentiometric determination using an ion-selective nitrate electrode causes problems in the presence of fairly large amounts of chloride or organic compounds with carboxyl groups. The polarographic method, on the other hand, is not only more rapid, but also practically insensitive to chemical interference, thus ensuring more accurate results. The limit of quantification depends on the matrix of the sample and is approximately 1 mg/L.

This Bulletin describes analysis methods for determining the following parameters: pH value, total titratable acid, ash alkalinity, formol number, total sulfurous acid, chloride, sulfate, calcium, and magnesium. These methods are suitable for the analysis of jams, fruit and vegetable juices, and their concentrates.

The water content of sweet liquorice is determined according to Karl Fischer. To dissolve the sample, a mixture of methanol and formamide is used as solvent and a high-frequency homogenizer as stirring device.

Determination of chloride, nitrate, and sulphate in sugar-containing solutions without matrix elimination using anion chromatography with direct conductometric detection.

Near-infrared spectroscopy (NIRS) is a fast, chemical-free analysis method for various quality parameters of chocolate bars without sample preparation. The NIRS solution is easy to use and can be used atline or in a quality control lab.

Near-infrared spectroscopy (NIRS) allows the simultaneous determination of sweeteners such as Stevia and sucralose in blends in less than one minute without any chemicals or sample preparation.

Determination of sucrose, glucose, and sucralose in a low-calorie sweetener using ion-exclusion chromatography with pulsed amperometric detection after post-column addition of sodium hydroxide.

Inulin is a mixture of many fructose molecules. Inulin is increasingly being used in food production in recent times. This Application Note describes the determination of the inulin content in cakes. Correct analysis requires knowing which type of inulin is present, because the total number of fructose units varies. In this task, for example, the F8 peak (eight fructose units) was quantified.

Polydextrose is a low-calorie, synthetic polymer made of glucose. It is a recognized additive for foodstuffs. Hot water is used to extract the polydextrose from the foodstuff, after which it is centrifuged. Subsequent fermentation removes maltooligomers and fructans. Afterwards, the polydextrose is quantified using anion-exchange chromatography with pulsed amperometric detection.