Changes in Individual Date Polyphenols and Their Relation to Browning

SUMMARY The main simple polyphenols of immature dates ( Phoenix dactylifera var. Deglet Noor) are flavans, flavonol glycosides, caffeoylshikimic acids, and a cinnamic acid derivative. Tannins are both water‐soluble and ‐insoluble condensed tannins of the leucoanthocyanidin type. Of the simple polyphenols, the flavans and caffeoylshikimic acids undergo the greatest decrease during maturation and storage. Tests with date phenolase show these compounds to be the most susceptible to enzymic browning. Several new phenols form during storage. Treatment of the tannins with hot strong acid produces cyanidin chloride, suggesting the presence of leuco‐cyanidin units in the tannins.