The Effects of Magnetic Fields on Viscosity, Color and pH of Longan Honey

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Vinyoo Sakdatorn


The magnetic fields were introduced in substitution of high temperature and prolonged heating during honey production with a promise of improved flowability and appearance of longan honey. The honey samples were exposed to magnetic fields of the permanent magnets for six hours at room temperature. The study was divided into two sets of magnetic fields depending on the maximum fields measured at the ends of the rod magnets. The lower magnetic fields were at 1400 G and 1600 G (samples F01 and F02), and the stronger magnetic fields at 4300 G (samples N01 and N02). The magnetically treated honey samples were then determined for any change of viscosity, color, pH, moisture content and total soluble solids (TSS) content. It was found that the honey samples subjected to the strong magnetic fields of 4300 G reduced their apparent viscosities from 6.7 Pa·s (control) to 6.1 Pa·s. The viscosity flow curves of all honey samples tested at the shear rates of 0.13 to 25 s-1 presented Newtonian behavior. The color space of all honey samples subjected to the magnetic fields showed increases in L* (from 26.43 to 29.59) and a* (from 3.12 to 5.22) values but decreases in b* values (from 12.09 to 11.12). As the result, color of the treated honey became lighter, more red and slightly yellow. In addition, the positive potential of hydrogen ions (pH) analysis showed that the honey samples became more acidic with stronger magnetic fields, and their pH values decreased from 4.23 (control) to 4.14, 4.16, 3.82, and 3.84 for the samples subjected to magnetic fields of 1400 G and 1600 G (F01, F02) and 4300 G (N01, N02), respectively. Moisture and TSS contents of all samples were, however, unaffected by the magnetic fields.


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Sakdatorn, V. (2018). The Effects of Magnetic Fields on Viscosity, Color and pH of Longan Honey. Naresuan University Engineering Journal, 12(2), 15–20. Retrieved from
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