Comparative analysis of the effects of different storage conditions on major royal jelly proteins

An experiment was carried out to analyse changes in the protein components of royal jelly (RJ) under different storage conditions, based on two dimensional electrophoresis (2-DE). The proteins identified were compared to those proteins already identified in the proteome complement of the RJ. The results showed that the total detected protein spots were 75,45,63 and 69, with molecular weight in the range of 7.64-72.33 kDa, isoelectric point 4.95-8.70, in the 2-DE image of RJ protein components stored at -20 degrees C for 80 days, 4 degrees C for 80 days, room temperature for 30 days, room temperature for 80 days, respectively. The spot of major royal jelly protein, apalbumin 1, was saturated in all images in this experiment, indicating that temperature has no significant effects on it. The spots number and the quantity of apalbumin 2 and apalbumin 3 did not increase or decrease following the temperature trend, suggesting they are also sensitive to temperature. However, spots of apalbumin 4 and glucose oxidase were observed only in the image of -20 degrees C for 80 days, and spots of apalbumin 5 were detected in the images of -20 degrees C and 4 degrees C for 80 days, indicating they are the proteins most sensitive to storage temperature and thus may be potential freshness markers for RJ, and that the best way to maintain quality of RJ is under freezing conditions.