Browsing by Subject "Quality control"

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High-performance thin-layer chromatography for the detection of compositional changes in LACTEM emulsifiers during storage
(2025) Schuster, Katharina; Blankart, Max; Hinrichs, Jörg; Oellig, Claudia
Quality control of food emulsifiers, such as lactic acid esters of mono- and diacylglycerols (LACTEM), is crucial in the reproducible production of food products. The current study investigated compositional changes of LACTEM emulsifiers using high-performance thin-layer chromatography (HPTLC) during storage at 60 °C for 8 weeks. Ultraviolet (UV) and fluorescence images of the HPTLC silica gel F254s plates after primuline derivatization and densitometric data were analyzed to assess changes in the composition. Significant changes were observed for minor LACTEM components (< 10% relative intensity), specifically a decrease in higher-lactylated monoacylglycerols and an increase in triacylglycerols. Techno-functional properties, such as particle size distribution, apparent viscosity, overrun, foam firmness, drainage, and residual cream of aerosol whipping cream (0.8 g 100 g−1 LACTEM) were investigated. While emulsion stability was not affected, the foam firmness increased significantly, corresponding to a visibly more brittle foam. On the basis of these results, monitoring compositional changes in the food-manufacturing process is necessary to maintain constant food quality.
Inter-laboratory comparison of plant volatile analyses in the light of intra-specific chemodiversity
(2023) Eckert, Silvia; Eilers, Elisabeth J.; Jakobs, Ruth; Anaia, Redouan Adam; Aragam, Kruthika Sen; Bloss, Tanja; Popp, Moritz; Sasidharan, Rohit; Schnitzler, Jörg-Peter; Stein, Florian; Steppuhn, Anke; Unsicker, Sybille B.; van Dam, Nicole M.; Yepes, Sol; Ziaja, Dominik; Müller, Caroline
Introduction: Assessing intraspecific variation in plant volatile organic compounds (VOCs) involves pitfalls that may bias biological interpretation, particularly when several laboratories collaborate on joint projects. Comparative, inter-laboratory ring trials can inform on the reproducibility of such analyses. Objectives: In a ring trial involving five laboratories, we investigated the reproducibility of VOC collections with polydimethylsiloxane (PDMS) and analyses by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). As model plant we used Tanacetum vulgare , which shows a remarkable diversity in terpenoids, forming so-called chemotypes. We performed our ring-trial with two chemotypes to examine the sources of technical variation in plant VOC measurements during pre-analytical, analytical, and post-analytical steps. Methods: Monoclonal root cuttings were generated in one laboratory and distributed to five laboratories, in which plants were grown under laboratory-specific conditions. VOCs were collected on PDMS tubes from all plants before and after a jasmonic acid (JA) treatment. Thereafter, each laboratory (donors) sent a subset of tubes to four of the other laboratories (recipients), which performed TD-GC-MS with their own established procedures. Results: Chemotype-specific differences in VOC profiles were detected but with an overall high variation both across donor and recipient laboratories. JA-induced changes in VOC profiles were not reproducible. Laboratory-specific growth conditions led to phenotypic variation that affected the resulting VOC profiles. Conclusion: Our ring trial shows that despite large efforts to standardise each VOC measurement step, the outcomes differed both qualitatively and quantitatively. Our results reveal sources of variation in plant VOC research and may help to avoid systematic errors in similar experiments.