Melissopalynological methodologies for investigating honey samples - a critical approach

Melissopalynological techniques are used in the analysis of pollen grains. However, the adoption of methodologies considering cost-effectiveness, shorter preparation time and lesser toxic procedures for researchers is relevant. Thus, this study aimed to analyze different melissopalynological methodologies in polyfloral honey samples. Three melissopalynological protocols were applied to the samples using alcian blue dye, basic fuchsin, and the traditional acetolysis methodology without dye. After preparing the pollen samples, and analyzing them under an optical microscope, six botanical families were recorded, e.g., Amaranthaceae, Asteraceae, Bignoniaceae, Fabaceae, Malvaceae, and Myrtaceae. The methodologies investigated proved to be efficient for detecting pollen structures and identifying botanical families thereof. The alcian blue dye-based protocol allowed a greater separation and discrimination of pollen grains as compared to the basic fuchsin and acetolysis ones, where pollen conglomerates were often identified. Even though acetolysis has been the most used method in melissopalynological studies, it has been claimed to offer risks to users due to the manipulation of corrosive and toxic solvents (i.e., H2SO4), also being lesser cost-effective and more time-consuming. Thus, considering the cost-effectiveness, the alcian blue dye and basic fuchsin-based methods seem to be preferred, being as efficient as acetolysis for identifying pollen grains.