Ellagic acid derivatives, ellagitannins, proanthocyanidins and other phenolics, vitamin C and antioxidant capacity of two powder products from camu-camu fruit (Myrciaria dubia).

ABSTRACT

The aims of this study were the evaluation of polyphenols and vitamin C content, and antioxidant capacity of dehydrated pulp powder and the dried flour obtained from the skin and seeds residue remaining after pulp preparation from camu-camu (Myrciaria dudia). Fifty-three different phenolics were characterised by HPLC-DAD-ESI-MS-MS and UPLC-HR-QTOF-MS-MS. The phenolic content of camu-camu flour was higher than that of the pulp powder (4007.95 mg/100 g vs. 48.54 mg/100 g). In both products the flavonol myricetin and conjugates, ellagic acid and conjugates and ellagitannins were detected. Cyanidin 3-glucoside, and quercetin and its glycosides were only found in the pulp powder, while proanthocyanidins were only present in the flour (3.5 g/100 g, mean degree of polymerisation 3). The vitamin C content was lower in pulp powder (3.5%) than in the flour (9.1%). The radical-scavenging capacity of both powders was determined by the DPPH, ABTS and ORAC assays, and was higher for camu-camu flour as could be expected for its higher phenolics and vitamin C content. Comparative analyses with fresh camu-camu berries indicate that some transformations occur during processing. Analysis of fresh berries showed that ellagic acid derivatives and ellagitannins were mainly present in the seeds, while proanthocyanidins were present both in the seeds and skin.