Investigation the differences in key taste-contributing substances between Shitougan(Citrus reticulata Blanco Cv. Manau Gan) and other citrus varieties

To elucidate the characteristic taste distinctions between Shitougan and other citrus species, the primary taste-contributing substances in the juice sac, segment membrane, albedo and epicarp of 9 citrus varieties, including Shitougan citrus, were analyzed. Our findings revealed that the distribution patterns and concentrations of sugars, organic acids, flavonoids and triterpenoids in different tissues determined the taste profiles of various citrus species. The outer tissues of citrus fruits were identified as the principal sites for accumulation of sugars, organic acids, flavonoids, and triterpenes. Notably, amino acids, such as arginine (Arg), glutamate (Glu), histidine (His), alanine (Ala), aspartic acid (Asp), and proline (Pro), played a pivotal role in shaping the overall taste characteristics of these citrus species. In particular reference to Shitougan fruit - its main edible components comprising juice sacs and segment membranes exhibited relatively lower levels of sugars and organic acids; however higher contents of naringin and neohesperidin were detected in four other tissues within Shitougan fruit. Furthermore, principal component analysis (PCA) indicated that naringin and neohesperidin were primarily responsible for conferring a unique bitter taste to Shitougan fruit. These comprehensive results effectively bridge existing knowledge gaps pertaining to taste-contributing substances specific to Shitougan fruit while simultaneously providing a solid theoretical foundation for further exploration into molecular mechanisms underlying important flavor-imparting constituents within this variety.