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ARS Home » Research » Publications at this Location » Publication #156534


item Jones, Gretchen

Submitted to: Grana
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2003
Publication Date: 1/1/2004
Citation: Jones, G.D., Bryant, V.M. 2004. The use of ETOH for the dilution of honey. Grana. 43:174-182.

Interpretive Summary: Pollen found in honey is used to determine a honey's type, pollen and nectar sources for honeybees, and the habitats and vegetation visited by honeybees. Water is generally used to dilute honey and remove pollen, but other techniques are needed because some pollen grains float on water and are lost during the pollen recovery process. Ethyl alcohol was used to dilute honey and compared to two techniques that used water for diluting honey. Alcohol-diluted samples had 526% greater pollen concentration values than short water-diluted samples, and 326% greater than long water-diluted samples. Ethyl alcohol-diluted samples produced 16% more pollen taxa than the short water-diluted technique, and 10% more pollen taxa than the long water-diluted technique. Because using ethyl alcohol to dilute honey increased the pollen sedimentation from honey, a more accurate determination of the honey's type, floral sources, and habitats utilized by honeybees can be made. In addition, the ethyl alcohol dilution will help to detect any changes in honeybee nectar and pollen sources that may occur as genetically modified plants are introduced into cropping systems.

Technical Abstract: Since the beginning of honey production, certain honey types are preferred because they taste better, are better for cooking, or do not rapidly crystallize. Pollen found in honey is used to determine the honey's type. Techniques used to extract pollen from honey vary in the amount of honey examined, the amount of water used to dilute the honey, and the time and speed of centrifugation. These variations address the disparity in pollen recovery that are due to the specific gravity and sinking rates of the different pollen types. Ethyl alcohol (ETOH) was used as a dilution liquid for honey and compared to two water-dilution techniques, one with a short centrifugation time (1 min) and the other using a long centrifugation time (10 min). The ETOH samples were centrifuged for 3 min. All samples were centrifuged at 4000 r.p.m. Significantly higher pollen concentration values were found in the ETOH-diluted samples. Pollen concentration values of the ETOH-diluted samples were 5.26 times greater than water-diluted, short centrifugation samples, and 3.26 times greater than water-diluted, long centrifugation samples. ETOH-diluted samples produced 16% more taxa than the water-diluted short centrifugation technique, and 10% more taxa than the water-diluted long centrifugation technique. The pollen spectra were not consistent across the three techniques. Additional research is needed to determine the efficiency of other ETOH concentrations in recovering pollen from honey. We recommend that the ETOH-dilution technique become the standard technique for the extraction of pollen from honey for pollen analyses because of the improved pollen recovery.