Identification and quantitative analysis of β-cryptoxanthin and β-citraurin esters in Satsuma mandarin fruit during the ripening process

In this study, to investigate the xanthophyll accumulation in citrus fruits, the major fatty acid esters of beta-cryptoxanthin and beta-citraurin were identified, and changes in their contents were investigated in two Satsuma mandarin varieties, 'Miyagawa-wase' and 'Yamashitabeni-wase', during the ripening process. The results showed that beta-cryptoxanthin and beta-citraurin were mainly esterified with lauric acid, myristic acid, and palmitic acid in citrus fruits. During the ripening process, beta-cryptoxanthin laurate, myristate, and palmitate were accumulated gradually in the flavedos and juice sacs of the two varieties. In the flayed of 'Yamashitabeni-wase', beta-citraurin laurate, myristate, and palmitate were specifically accumulated, and their contents increased rapidly with a peak in November. In addition, functional analyses showed that CitCCD1 and CitCCD4 efficiently cleaved the free beta-cryptoxanthin, but not the beta-cryptoxanthin esters in vitro. The substrate specificity of CitCCDs towards free beta-cryptoxanthin indicated that beta-cryptoxanthin esters might be more stable than free beta-cryptoxanthin in citrus fruits. (C) 2017 Elsevier Ltd. All rights reserved.