Application of accelerated heteronuclear single quantum coherence experiments to the rapid quantification of monosaccharides and disaccharides in dairy products

Abstract

Monosaccharides and disaccharides are important dietary components, but if insufficiently metabolized by some population subgroups, they are also linked to disease patterns. Thus, the correct analytical identification, quantification, and labeling of these food components are crucial to inform and potentially protect consumers. Enzymatic assays and high‐performance anion‐exchange chromatography with pulsed amperometric detection are established methods for the quantification of monosaccharides and disaccharides that, however, require long measuring times (60–180 min). Accelerated methods for the identification and quantification of the nutritionally relevant monosaccharides and disaccharides d‐glucose, d‐galactose, d‐fructose, sucrose, lactose, and maltose were therefore developed. To realize this goal, the NMR experiments HSQC (heteronuclear single quantum coherence) and acceleration by sharing adjacent polarization (ASAP)‐HSQC were applied. Measurement times were reduced to 27 and 6 min, respectively, by optimizing the interscan delay and applying non‐uniform sampling. The optimized methods were used to quantify d‐glucose, d‐galactose, d‐fructose, sucrose, and lactose in various dairy products. Results of the HSQC and ASAP‐HSQC methods are equivalent to the results of the reference methods in terms of both precision and accuracy, demonstrating that these methods can be used to correctly analyze nutritionally relevant monosaccharides and disaccharides in short times.

Quantification of Isomaltulose in Food Products by Using Heteronuclear Single Quantum Coherence NMR-Experiments

“…Moreover, the determined isomaltulose content did not change when the larger interscan delay of 6.0 s was applied (product 3). The same held true for D-fructose, which was exemplarily re-analyzed here (15). Thus, shortening of the interscan delay to 1.5 s in the HSQC experiment did not negatively affect the quantification of isomaltulose.…”

“…S3. matrices has already been demonstrated in a previous study (15). Both the HSQC methods with NUS coupling and the ASAP-HSQC methods quantify isomaltulose, D-fructose, and D-glucose equivalently to the reference method HPAEC-PAD.…”

“…with additional sugars (15). Isomaltulose shows signals in the HSQC spectrum that are nicely separated from diagnostic signals of other sugars.…”

“…We demonstrated in a previous work that HSQC experiments with lower interscan delays can be used to quantify d -glucose, d -fructose, d -galactose, sucrose, lactose, and maltose in dairy products, thereby significantly reducing experiment times ( 15 ). Non-uniform sampling (NUS) was also applied to shorten the measurement time by recording only a randomly distributed portion of data points ( 15 ). The missing data points are added after the measurement by reconstruction algorithms ( 16 ).…”

“…The missing data points are added after the measurement by reconstruction algorithms ( 16 ). An additional reduction of the measurement time can be achieved by using the measurement time reduced acceleration by sharing adjacent polarization (ASAP)-HSQC method, which generates HSQC spectra that are sufficiently resolved for quantification in a few minutes ( 15 , 17 ).…”