Physico-chemical quality characteristics of royal jelly from three regions of Bulgaria
2012
Balkanska, R., Institute of Animal Science, Kostinbrod (Bulgaria) | Zhelyazkova, I., Thracian University, Stara Zagora (Bulgaria) | Ignatova, M., Institute of Animal Science, Kostinbrod (Bulgaria)
The objective of the present study is to investigate the composition and physico-chemical properties of fresh royal jelly- RJ, samples from Sofia n=5, Lovech n=5 and Varna n=3, produced from May to August 2011. The samples were kept frozen at -20° C before analysis. The parameters of royal jelly samples obtained from Sofia region varied within the following ranges: water content 61.7 – 65.2%, proteins 15.07 – 16.85%, fructose 3.73 – 5.05%, glucose 2.01 – 3.70%, sucrose 1.50 – 2.27%, total sugars 8.05 – 10.37%, pH 3.94 – 4.06, total acidity 3.86 – 4.51 ml 0.1 N NaOH/g and electrical conductivity 180 – 206 μS/cm. The samples from Lovech region gave the following results: water content 59.10 – 62.70%, proteins 16.84 – 19.63%, fructose 4.07 – 5.47%, glucose 3.69 – 5.28%, sucrose 0.36 – 3.59%, total sugars 8.12 – 13.48%, pH - 3.86 – 3.97, total acidity - 3.68 – 4.42 ml 0.1 N NaOH/g and electrical conductivity - 196 – 216 μS/cm. Fructose, glucose, sucrose and total sugars contents are in the range 3.64–4.27%, 2.69 – 5.87%, 2.28 – 3.44%, 9.15 – 12.87%, respectively for the samples from Varna region. The minimum and maximum values for other parameters are: water content - 63.30 – 65.80%, proteins - 12.23 – 13.08%, pH - 3.60 – 3.70, total acidity 2.48 – 4.23 ml 0.1 N NaOH/g, electrical conductivity - 173 – 181 μS/cm. Because of the small number of samples and absence of information about additional feeding of bees with sugar solution, it should be insufficient to draw conclusion about the prevalence of glucose or fructose in fresh royal jelly. This work indicated slight differences between the obtained results of royal jelly samples from three regions of Bulgaria.
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