Floating Sphere Assay: A rapid qualitative method for microvolume analysis of gelation

1AbstractA huge, unprecedented demand for gelatin coupled with its implications on global sustainability has resulted in the need to discover novel proteins with gelling attributes for applications in the food industry. Currently used gelation assays require large sample volumes and thus the screening for novel gelling proteins is a formidable technical challenge. In this paper, we report the ‘Floating Sphere Assay’ which is a simple, economical, and miniaturized assay to detect minimum gelling concentration with volumes as low as 50 μl. Results from the Floating Sphere Assay are consistent with currently used methods for gelation tests and accurately estimate the Minimum Gelling Concentrations (MGCs) of gelatin, κ-carrageenan and gellan gum. The assay was also able to differentiate the strengths of strong and weak gellan gum gels prepared at pH 3.5 and pH 7.0 respectively. The Floating Sphere Assay can be utilized in high-throughput screens for gelling proteins and can accelerate the discovery of gelatin substitutes.2HighlightsWe report the Floating Sphere Assay that can be used to assesses minimum gelling concentration of solutions with volumes as low as 50 μl.Observing whether a glass sphere placed on the surface of a test solution floats or sinks is diagnostic of gel formationFloating Sphere Assay can distinguish a strong gel from a weak gelFloating Sphere Assay is a rapid and cost-effective approach to screen for novel plant-based gelatin alternatives.