Deciphering the color codes of five-color glutinous rice based on UPLC-Q-Exactive-Orbitrap MS/MS

Five-color glutinous rice, a traditional delicacy from Guangxi, owes its vibrant hues to natural plant dyes. Using UPLC-Q-Exactive-Orbitrap system, we systematically characterized the colorants for the first time. Black arises from an Fe3+-gallic acid complex formed in iron pots from Liquidambar formosana Hance leaves; red and purple is imparted by the alkaloids constituents such as peristrophine, zilanine and perisbivalvine B in Peristrophe bivalvis (L.) Merr. aerial parts; yellow and blue originate from the flavonoid constituents such as linarin in Buddleja officinalis Maxim. inflorescence and the anthocyanins constituents such as ternatin B1, D1 and D2 in Clitoria ternatea L. flower, respectively. These natural pigments are non-toxic, rich in antioxidants and offer nutritional benefits, providing a scientific basis for their extraction, functional-food development and standardized production of this heritage food.