The First Anthocyanins appearing during the Ripening of Blueberries

Abstract

ALTHOUGH a great deal is known of the anthocyanins of berries and other fruit, this knowledge is still quite superficial and fragmentary¹. How and in what order the anthocyanins develop in the maturing berries has only been clarified in one case : the first anthocyanin compound to appear in Californian ‘Cabernet’ grapes was found to be the malvidin-3,5-diglucoside ; with advanced ripening of the grapes, malvidin-3-glucoside and delphinidin-3,5-diglucoside develop at almost the same time, while petunidin-3,5-diglucoside is the last to be formed². Free malvidin was not observed in the grape skins until one week after the berries had developed the purple-red colour of complete maturity. These observations are noteworthy because they show that anthocyanins and not anthocyanidins are the first to appear during maturation. Furthermore, the first anthocyanin formed, malvidin-3,5-diglucoside, has quite a complicated structure. This anthocyanin is considered to be the dominant pigment in these grapes.