Degradation of Phytochemical and Antioxidant Capacity of Noni (Morinda Citrifolia L.) Pulp Tea during Drying and Roasting Treatment

Abstract

Noni (Morinda citrifolia L.) fruit is highly evaluated as an important herb with a good source of natural antioxidant against various ailments as well as maintain overall good health. It’s normally disposed due to unpleasant aroma from the ripened fruit. There is limited literature mentioned to the decomposition of this valuable fruit during thermal processing. Hence this reseach aimed to evaluate the possible degradation of total phenolic (mg GAE/100 g), total flavonoid (mg QE/100 g), DPPH radical-scavenging ability (mM TE/100 g), FRAP ferric reducing antioxidant power assay (mM TE/100 g) in raw, dried and roasted noni pulp tea. The highest contents of functional constituents and antioxidant capacity were noticed in the raw sample; meanwhile decreased dramatically in the roasted one. However, degradation of noni flavonol glycosides during roasting could produce aglycone metabolites, which in turn, may lead to increased bioavailability. Owing to degradation of phytochemical and antioxidant ability by harsh thermal treatment, it’s necessary to be careful in drying and roasting to limit detrimental effect in herbal noni tea production.