Analysis of rose orange fruit quality during different growth periods

【Objective】The physical and chemical properties and the changes of organic acids,total flavonoids,total phenolics contents and other active components of rose oranges at different growth stages were studied for analyzing the active components in different fruit issues to provide scientific basis for rose oranges quality identification and the utilization of their by-products.【Method】The total sugar content in fruit juice at different growth periods(2020.9.20-2021.1.20) was determined by the anthrone-sulfuric acid method,and the total acid content was determined by the sodium hydroxide neutralization titration method. The contents of main flavonoid compounds in fruit peel,pomace,juice and organic acids and soluble sugars in juice during different growth periods were analyzed by HPLC. The contents of total phenolics contents in fruit peel,pomace and juice was determined by Folin-Ciocalten method. The antioxidant capacity was determined by DPPH,FRAP and ABTS methods.【Result】From September,2020 to January,2021,as the fruits grew and developed, the weight of single fruit,pH,sugar acid ratio and soluble solids of rose oranges increased gradually. The content of citric acid and acetic acid decreased significantly(P<0.05,the same below),while the content of malic acid increased. The content of fructose and glucose decreased gradually,while the content of sucrose increased by 4.03 times. The content of total flavonoids and total phenolics contents and antioxidant capacity in peel,pomace and juice decreased gradually. The total phenolic content of rose orange fruits was in the order of peel>pomace>juice. The content of total phenolics contents in peel decreased from 1.84 mg GAE/g to 0.89 mg GAE/g. The content of tangeretin,didymin,hesperidin,sinensetin and nobiletin significantly decreased. No tangeretin,sinensetin and nobiletin were detected in fruit juice and pomace,and the contents of hesperidin and didymin were in the order of pomace>peel>juice. The total antioxidant capacity of peel was 1.34 times that of pomace and 2.16 times that of juice.【Conclusion】With the ripening of rose orange fruits,sucrose content increases significantly,while the contents of fructose,glucose,total phenolics contents,total flavonoids and antioxidant activity significantly decrease. The changes of physical and chemical properties,main nutrients and active components of rose orange fruits in different growth periods can provide a reference for the quality control of rose orange fruits and the comprehensive development and utilization of different parts.