Determination of carbohydrates in juices by capillary electrophoresis, high‐performance liquid chromatography, and matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry

Abstract

The objective of this work was to develop a sample preparation procedure for determination of the carbohydrate profiles in commercial juice samples by three principally different analytical methods: capillary electrophoresis (CE) with indirect detection, high-performance liquid chromatography (HPLC), and matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). The preparation and purification of juice samples prior to analysis is described. The method using Carrez reagents was found to be an efficient preparation tool for all three methods. The addition of Carrez reagents to the samples for mass analysis improved the quality of the mass spectra of oligosaccharides. The amounts of glucose, fructose, and sucrose as major carbohydrates in fruit juices measured by CE using a simple instrument are in good agreement with the HPLC values and the data declared by the producers of the juices. The results from both methods are critically evaluated and their impact for studies of authenticity is discussed. The decrease of sucrose amount during the storage of samples was explained by acid hydrolysis of this disaccharide.

Evaluation of microfiltration and heat treatment on the microbiological characteristics, phenolic composition and volatile compound profile of pomegranate (Punica granatum L.) juice

“…The analysis of carbohydrates was performed according to Cabálková et al . Each sample was centrifuged at 8000 × g for 10 min, then the supernatant was filtered through a 0.45 µm membrane filter and properly diluted in water/acetonitrile (25:75 v/v).…”

Synthesis of β‐Galactooligosaccharides from Lactose Using Microbial β‐Galactosidases

“…It has been suggested that the use of carrez reagents (potassium hexacyanoferrate(II) 3‐hydrate, potassium ferrocyanide, and zinc sulfate) and perchloric acid might be useful in protein clarification and precipitation from dairy‐based matrices to overcome inherent obstacles in GOS analysis from these products (Cabálková and others 2004). Carrez reagents present problems with residual proteins that would affect column operation during HPLC analysis, while perchloric acid creates a highly acidic medium that eventually requires neutralization with a strong alkali, thus complicating further the analytical process.…”

Capillary electrophoresis in food authenticity

“…Under optimized conditions 28 carbohydrates (mono-and disaccharides, sugar alcohols, amino sugars) were separated in less than 25 min. Cabµlkovµ et al developed simple CE methods at pH 12.5 (sodium phosphate + naphthol blue-black) with indirect detection at 570 nm for the separation of fructose, glucose, and sucrose in juices [52]. CE results of sugar content in commercial juices were in good agreement with those obtained by HPLC.…”