Study On Quality Analysis And Isotope Fingerprint Information Of Korla Fragrant Pear

Korla fragrant pear is a famous,special and high-quality fruit in Xinjiang,and it is also a protected product of geographical indications mutually recognized by China and Europe.Exploring the fruit quality changes and isotope fingerprint information of Korla fragrant pears in different growth periods is of great significance for mining the characteristic quality of Korla fragrant pears,product quality evaluation and origin protection.In order to clarify the quality changes of Korla fragrant pears during the ripening process,determine the high-quality fragrant pear planting areas,and explore the isotope fingerprint information of fragrant pears,this study used the Korla fragrant pears from 60 to 150 days after anthesis and the mature Korla fragrant pears from different origins.A systematic experiment and analysis were carried out for the object.The main research results obtained are as follows:1.During the fruit growth period,the weight,longitudinal diameter,transverse diameter,soluble solid content,reducing sugar content,fructose content,glucose content,sucrose content,and citric acid content of Korla fragrant pears showed an overall increasing trend.After 150 d)reach the maximum value.The hardness,total acid content,malic acid content,tartaric acid content,and polysaccharide content of Korla fragrant pears all showed a downward trend,and reached the minimum when fragrant pears were ripe（150 d after flowering）.The content of sorbitol increased first and then decreased.When the fragrant pear matures（150d after flowering）,its content is similar to that at the early growth stage（60 d after flowering）,and there is no significant difference between the two（P>0.05）.2.Through the establishment of HPLC-RID method to determine the content of 8 kinds of sugars in fragrant pear fruit,including glucose,fructose,sucrose,sorbitol,xylitol,ribose,ribitol,mannan,etc.,it is found that the main sugars in fragrant pear fruit are Glucose,fructose,sucrose,sorbitol;xylitol,ribose,ribitol,mannan were not detected in the pear fruit.3.From 60d to 90d after flowering,the fruit mainly accumulates sorbitol,and from 105d to 150d after flowering,it mainly accumulates fructose.When the fruit matures,fructose is the highest sugar content;throughout the growth period,Malic acid is the organic acid with the highest content,and it is also the organic acid that contributes the most to the formation of Korla fragrant pear quality.4.The correlation analysis between the physical indicators and quality indicators of the fragrant pear fruit found that the weight of the fruit was significantly positively correlated with the glucose content,and significantly negatively correlated with the polysaccharide and tartaric acid content;As the fruit weight increases,the glucose content gradually increases,while the polysaccharide and tartaric acid content gradually decreases.The citric acid content and the tartaric acid content are extremely significantly negatively correlated,indicating that as the tartaric acid content decreases,the citric acid content gradually increases.5.Apply the principal component analysis method to comprehensively evaluate the fruit quality of Korla fragrant pears from different producing areas,and extract 3 principal components greater than 1,the cumulative contribution rate reached 79.715%,reducing sugar,sugar-acid ratio,glucose,sorbitol,Total acidity is the main index that affects the quality of Korla fragrant pear.From the perspective of comprehensive scores,the quality of Korla fragrant pears in Kuqa City,Korla City,Yuli County,and Luntai County is relatively good;the quality of fragrant pears in Aksu City,Awati County,and Xinhe County is relatively poor,which requires improvement in horticulture.Measures to improve the quality of fragrant pears.6.There are significant differences inδ¹³C,δ²H,andδ¹⁸O in pulp,peel and core（P<0.05）;δ¹³C,δ¹⁵N,andδ¹⁸O in pulp and peel are significantly correlated;δ²H andδ¹⁸O in fruit juice are significantly different from each other.Irrigation water tends to be the same,and theδ²H value in the pulp（freeze-dried powder）is close to that of irrigation water,but theδ¹⁸O value of the two is significantly different（P<0.05）.The Korla fragrant pear fruits from different producing areas have obviously differentδ²H andδ¹⁸O distributions,indicating thatδ²H andδ¹⁸O isotope fingerprints can be used as important indicators for the identification of origin.7.There is a significant correlation between the Sr content in fragrant pear peel and pulp,and the content in the skin is greater than the pulp content,so the peel is more suitable for analyzing the Sr isotope composition of fragrant pear.⁸⁷Sr/⁸⁶Sr can be used to discriminate the origin of fragrant pears in Xinjiang and Gansu,but it is not suitable for discerning the origin of fragrant pears in Xinjiang and Shanxi.In this study,the quality of Korla fragrant pears during the growth period was analyzed,and the changes in quality indicators such as sugar,acid,and soluble solids were clarified.The principal component analysis method was used to evaluate the quality of Korla fragrant pear fruits from different producing areas,and the production areas with better fruit quality such as Kuqa City,Korla City,Yuli County and Luntai County were screened out.The C,N,H,O,Sr isotopes of Korla fragrant pear fruits from different producing areas were determined.The results showed thatδ2H andδ18O isotope fingerprints can be used as important indicators for the identification of the origin;87Sr/86Sr can be used to identify the origin of Xinjiang and Gansu fragrant pears.In order to protect the Korla fragrant pear brand and promote the development of the Korla fragrant pear industry,it provides a research basis and theoretical basis.