Studies On Quality Control Of Royal Jelly Based On Chromogenic Reaction Between Royal Jelly And HCI And Fatty Acid Compostion

Long-term research and practice showed that royal jelly (RJ) spoils easily under room temperature, which indicates that freshness is closely related to its quality. However, freshness is not involved in national standard of RJ because of lacking of simple, effective and widely accepted detection methods. The content of trans-10-hydroxy-2-decenoic acid (10-HDA) is the most important marker in RJ, which directly determines the price of RJ in commercial trade. However, the10-HDA content declines a lotcompared to several years ago, which affects the export and native consumption. As a result, researches on RJ freshness and quality control that providing theoretical support and basic data is urgently necessary.In this study, a simple, fast and effective freshness assessment method was established based on a chromogenic reaction between RJ and HC1. Elevation of10-HDA content in RJ was achieved by feeding organic acids. And also, the factors which could influence10-HDA content were analyzed based on a large amount of samples with different origins. The results were showed as follow:1. A new RJ freshness measurement method was established based on a chromogenic reaction between RJ and HC1. The a*and b*value change as the freshness, the varying patterns differ a little between RJ produced on various kinds of pollen and on rape pollen. For RJ produced on various kinds of pollen: According to Y (Y=a*-b*) value, samples stored at RT got a good separation before and after7d,9d and21d. Discrimination analysis results showed that samples stored at different temperature for different storage could be correctly classified into proper freshness intervals based on RT samples.For RJ produced on rape pollen: according to a*value, samples at RT could be divided into0-7,9,11-17,21,28and35-57d intervals; While using b*value,0-11,14-17and21-57d intervals could be set. Based on a*and b*value, discrimination analysis showed a good classification of RT samples into0-11,14-17and21-57d intervals, and samples stored at different conditions could be correctly classified into proper freshness intervals based on RT samples.2. A gas chromatography (GC) method for detection of10-hydroxydecanoic acid (10-HDAA),3-hydroxydecanoic acid (3-HDAA) and sebacic acid was developed for the first time. Using this method combined with10-HDA detection method in national RJ standard,10-HDA,10-HDAA,3-HDAA and sebacic acid content in RJ produced before and after feeding with organic acids were detected. The results indicated that,10-HDA and sebacic acid could be elevated by5.6%-6.4%and22%-46%, respectively, by feeding citric or stearic acids. The content of10-HDAA and3-HDAA arised by14.4%-20.0%and10.6%-23.4%, respectively, after feeding citric acid.3. Factors influencing10-HDA content were studied systematically based on a large number of samples. The content of10-HDA could be affected by both geography and bee breed, in China, Western Group (2.01%)> Northeastern Group (1.87%)> Eastern Group (1.75%), Apis mellifera ligustica×A. m. carnica (1.89%)> A. m. ligustica (1.79%), geography is the dominant factor. The content of10-HDA in RJ produced on rape pollen is significantly higher than that in RJ on vitex pollen. A significant negative correlation between yield and10-HDA content of RJ has been observed, the correlation coefficient of these2parameters is-0.362for RJ produced during rape flowering season and-0.432for that produced on various kinds of pollen.