| Dark Plum(Wumei,the almost ripe and dried fruit of Prunus mume(Sieb.)Sieb.et Zucc.)is a kind of traditional Chinese medicine.It has the functions of astringing lung for relieving cough,relieving diarrhea with astringents,promoting production of fluid to prevent thirst and calming intestinal ascaris.Food is used as a drink,preserved fruit,etc.The main components are organic acids,amino acids,flavonoids,sugars,etc.Now Dark Plum mainly produced in Sichuan,Yunnan and Fujian.There are different times to collect the Plum fruits on the other hand there are different producing methods in different origins areas of Dark Plum.The result is a difference in quality.Therefore,this research established some methods for determining the content of amino acids,organic acids,5-hydroxymethylfurfural,mumefrual and flavonoids in Dark Plum,and then comprehensively evaluated the quality of Dark Plum from different producing areas.Finally the main factor processing temperature was studied in order to provide a scientific basis for the quality evaluation and processing production of Dark Plum.The content of this thesis includes the following six aspects:First,the determination of 17 amino acids in Dark Plum: the consumption of Dark Plum in food is greater than the amount of medicinal.Amino acid is the nutrient component of the human body.It is the cornerstone of proteins,peptides,neurotransmitters,nutrients,antibiotics and transporters in human body.It can be used as one of the indicators for quality evaluation of Dark Plum.To this end,by optimizing the chromatographic conditions,a method for the determination of 17 amino acids in Dark Plum by pre-column derivatization with phenyl isothiocyanate was established.The separation effect of 17 kinds of amino acids was good,and the recovery rate was over 94.73%.Using this method,42 samples of Dark Plum from different origins were determined.The total amount of 17 amino acids in the Dark Plum samples was 4.005 mg/g(n = 22,Sichuan),2.791 mg/g(n = 10,Yunnan)and 2.561 mg/ g(n = 10,Fujian).Sichuan Dark Plum samples has the highest total amino acid content,followed by Fujian and then is Yunnan.It is indicated that the method can accurately determine the content of amino acids in Wumei from different producing areas and evaluate its quality.Second,the determination of 10 kinds of organic acids in Dark Plum: The organic acid in Dark Plum is an important material basis for its medicinal properties;the reports that Dark Plum has antibacterial,anti-inflammatory,anti-fibrinolytic,anticoagulant,and liver functions have a certain relationship with organic acids.The content of eight organic acids has been determined in the references;since both α-ketoglutaric acid and fumaric acid are active ingredients,they should be the indicator components for the quality evaluation of Dark Plum.To this end,this paper established a HPLC method for the determination of 10 organic acids in Dark Plum.The chromatographic peaks of the 10 organic acids were well separated,and the recovery was above 94.02%.42 samples of Dark Plum from different producing areas were determined.The total amount of organic acids was 282.08 mg/g(n = 22,Sichuan),241.89 mg/g(n = 10,Yunnan)and 298.63 mg/g(n = 10,Fujian).Fujian Dark pulms has the highest total organic acid content,followed by Sichuan samples and then is Yunnan samples.It is indicated that the method can accurately determine the content of organic acids in Dark Plum from different producing areas and evaluate the quality of Dark Plum.Third,determination of 5-hydroxymethylfurfural and mumefural in Dark Plum: 5-hydroxymethylfurfural and mumefural have an effect of improving blood flow and fighting influenza virus.Ingredients such as sugars,amino acids,and organic acids contained in the Dark Plum are prone to Maillard reaction during processing,resulting in the active ingredient intermediate 5-hydroxymethylfurfural and the further product mumefural.To this end,a chemical reaction between fructose and citric acid to form mumefural was carried out to prepare a reference substance for separation of mumefural,and a method for simultaneously determining the content of 5-hydroxymethylfurfural and mumefural in Dark Plum was established by HPLC.The contents of two components in different processing Dark Plum samples from 42 producing areas in Sichuan,Yunnan and Fujian were determined.The results showed that the content of 5-hydroxymethylfurfural in the Dark Plum samples was 0.638 mg/g(n = 22,Sichuan),0.207 mg/g(n = 10,Yunnan)and 0.916 mg/g(n = 10,Fujian),the highest content of 5-hydroxymethylfurfural,followed by Sichuan,again Yunnan.The content of mumefural in the Dark Plum samples was 0.635 mg/g(n = 22,Sichuan)and 0.530 mg/g(n = 10,Fujian).The content of mumefural was the highest in Sichuan,followed by Fujian,and not detected in Yunnan samples.The method is applicable to different processed Dark Plum samples,and provides a method basis for the component transformation research and quality evaluation of chemical reaction in Dark Plum processing.Fourth,the determination of total flavonoids in Dark Plum: The total flavonoids in Dark Plum have antioxidant and antibacterial effects,and can be used as one of the indicators for quality evaluation of Dark Plum.To this end,using rutin as a reference,a method for the determination of total flavonoids in Dark Plum by ultraviolet-visible spectrophotometry was established.The results of the methodological investigation show that the determination results of this method are accurate.At the same time,42 samples of Dark Plum from different producing areas in Sichuan,Yunnan and Fujian were determined.The total flavonoids were 15.271 mg/g(n = 22,Sichuan),29.782 mg/g(n = 10,Yunnan)and 9.485 mg/g.(n = 10,Fujian).Yunnan Dark Plum has the highest total flavonoid content,followed by Sichuan and then is Fujian samples.It indicates that the quality of the Dark Plum samples from different methods is different.Fifth,a comprehensive comparison of the quality of Dark Plum from different producing areas: 42 samples of Dark Plum were collected from Sichuan,Yunnan and Fujian,and their color was measured first,then their amino acids,organic acids,5-hydroxymethylfurfural,mumefural and total flavonoids were determined.The content of the samples was analyzed by principal component analysis.The results showed that the comprehensive scores of 22 Sichuan Dark Plum samples had 10 positive numbers and 12 negative numbers with an average of 0.206(n = 22).One of the 10 samples of Yunnan Dark Plum was positive,with an average of-1.018(n = 10);the remaining 9 were negative.Of the 10 samples of Fujian Dark Plum,7 were positive and 3 were negative,with an average of 0.564(n = 10).It shows that the quality of the Dark Plum in the three major producing areas is different,Fujian is the best,Sichuan is the second,and Yunnan is again.Sixth,the comparison of processing temperature of Dark Plum: After harvesting,the fresh fruit of Dark Plum needs to be processed to become a medicinal material.Since the harvesting time is mostly in summer,due to the humid weather,it is often dried by heating;during the heating process,Maillard reaction occurs,etc.,and these reactions are often affected by temperature.To this end,the harvested Dark Plum fresh fruit is processed at six different temperatures,such as 30℃,45℃ 60℃,75℃,90℃,and 105℃,to determine the color,and then determine the amino acid and organic acid,respectively,5-hydroxymethylfurfural,mumefural and total flavonoids.The results showed that the content of active ingredients in different temperature processed samples was different,and the content of amino acids,organic acids and flavonoids decreased.The higher the temperature,the more the active ingredient content decreased.Further,a mumefural-like black macromolecular compound is produced to darken the color.According to the comprehensive analysis of the color and the content of the four active ingredients,the scores of the six different temperature processing Dark Plum were 2.15,1.32,0.59,-0.48,-1.15,-2.43,respectively.Although the highest score is obtained at 30℃ drying,considering the low processing temperature and the long processing time in practical applications,the temperature can be appropriately controlled at 30 ～ 60℃ to ensure the quality of Dark Plum.In addition,the processing research of Dark Plum were reviewed to provide a scientific basis for improving the quality of Dark Plum. |
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