Study On Extraction And Freshness-keeping Effect Of Water Soluble Protein From Royal Jelly

Royal jelly(RJ)is a super nutritious food which can be eaten directly by human beings and can be absorbed very well.Its various biological activities are closely related to its rich protein.The water-soluble protein in royal jelly accounts for about 46-89% of the total amount of royal jelly protein,which is the most important active ingredient in royal jelly.At present,royal jelly is mainly eaten fresh or processed into freeze-dried powder,but its application in other fields is very rare.Therefore,the study on the water-soluble protein of royal jelly and its fresh-keeping effect in chilled pork is of great significance,which provides the experimental basis for the development of new natural preservative for meat.1.In this paper,water extraction acid precipitation method and water extraction ammonium su lfate precipitation method were used to optimizate the extraction process of water-soluble protein fr om royal jelly through single factor experiments,plackett-burman and response surface optimization analysis.The result showed tha the best conditions of water extraction acid precipitation method to extract for royal jelly water-soluble protein was that,centrifugal speed was 10000 r/min,centrifugati on time was 25 min,material water mass ratio was 1:20,ultrasonic extraction time was 41 min a nd precipitation time was 43 min.Under the best condition,the average value of water-soluble pro tein extraction rate from royal jelly was 69.97%.The best conditions of water extraction ammonium sulfate precipitation method to extract for water-soluble protein in royal jelly was that.material w ater mass ratio was 1:20,ultrasonic extraction time was 40 minutes,ammonium sulfate saturation was 89%,pH 5 and precipitation time was 50 minutes.Under the best condition,the average value of water-soluble protein extraction rate from royal jelly was 80.22%.2.Water extraction acid precipitation method and water extraction ammonium sulfate precipitat ion method were good extraction method for water-soluble protein from royal jelly.By comparing the extraction rate of water-soluble protein from royal jelly obtained by the two methods,it could be seen that water extraction ammonium sulfate precipitation method was more suitable for the ext raction of the water-soluble protein from royal jelly than the water-extraction acid precipitation met hod.3.In this paper,Sephadex G-100 and Sephadex G-75 gel chromatography combined with SDS-PAGE gel electrophoresis were used to isolate water-soluble proteins from royal jelly.Separation r esult showed that,there were at least 10 bands in the water-soluble protein of royal jelly by the r esults of SDS-PAGE gel electrophoresis,and the main protein bands were concentrated in the rang e of 44-77 kD.The three peaks obtained by Sephadex G-100 were about 60 kD,58 kD and 49 k D,63 kD,58 kD and 52 kD,55 k D and 50 kD through SDS-PAGE gel electrophoresis.The two peaks obtained by Sephadex G-75 are about 69 kD,60 kD and 50 kD,51 kD and 44 kD through SDS-PAGE gel electrophoresis.4.For the separation of water-soluble protein of royal jelly,Sephadex G-100 was better than Sephadex G-75.5.In this paper,the water-soluble protein of royal jelly was applied to chilled pork to keep fr esh,comparied and compounded with natural preservative tea polyphenols.By comparing the pH,T VB-N,TBARS,total number of bacterial colony in each group pork Storaged 1,3,5,7,9,11 days at 4?,The results showed that pH of the chilled pork in the control group and each treatment grou p during 1-11 days of storage all showed the trend of decreasing first and then increasing,TVB-N,TBARS and total number of bacterial colony all showed varying degrees of upward trend with the extension of storage time.In the treatment group,the pH,TVB-N,TBARS and total number of bact erial colony of chilled pork treated by the water-soluble protein of royal jelly,tea polyphenols alo ne were all Significantly lower than those of the control group,the pH,TVB-N,TBARS and total n umber of bacterial colony of chilled pork through complex treatment were all Significantly lower t han thos of the treatment group handled alone.The spoilage bacteria in each group of spoiled pork were isolated and purified.The character istics of colony,morphology of bacterial cells,partial physiological and biochemical experiments,the result of DNA sequencing and construction for phylogenetic tree were used to identify the spoilag e bacteria.The results showed that four strains of spoilage bacteria isolated and purified from chill ed pork of the control group,identified as Serratia fonticola,Macrococcus sp.,Hafnia alvei and B acillus subtilis.Two spoilage bacteria isolated and purified from the chilled pork treated alone by t he water-soluble protein of royal jelly and tea polyphenols,identified as Serratia fonticola and Bac illus subtilis.One spoilage bacteria isolated and purified from the chilled pork treated by compositepreservation solution processing,identified as Serratia fonticola.6.The water-soluble protein of royal jelly and tea polyphenols could prolong the preservation period of chilled pork for 2-4 days,the complex of two fresh-keeping liquid could prolong the p reservation period of chilled pork for 3-4 days.The water-soluble protein of royal jelly,tea polyphenols and the complex fresh-keeping liquid had a good inhibitory effect on Macrococcus sp.and Hafnia alvei,the complex fresh-keeping liqui d also had a good inhibitory effect on Macrococcus sp.and Hafnia alvei and Bacillus subtilis.