Contribution of glycosidically bound compounds to aroma potential of jackfruit (Artocarpus heterophyllus lam)

Abstract

Volatile compounds are present in fruits in two forms, free and glycosidically bound. The latest has been studied in several fruits and are considered important aroma precursors because their release by acid or enzymatic hydrolysis has been reported higher than the free fraction. Recently, volatiles released by acid hydrolysis in jackfruit were reported, however, enzymatic hydrolysis of glycosidically bound fraction has not been studied yet. Thus, in this study, the free and glycosidically bound volatile compounds from jackfruit were isolated by absorption onto a column of Amberlite XAD-2. Enzymatic hydrolysis with β-glucosidase was carried out to release the glycosidically bound compounds and identified by GC–MS. Fifty-four volatiles encompassed both fractions with 14 compounds in common. 2,4-dimethylbenzaldehyde, 4-methylpentan-2-ol, 2,6-dimethylheptan-4-one, neral, butan-1-ol, and hexadecanoic acid were prominent in the free fraction. Meanwhile, 3-hydroxy-β-ionol, 2-phenylethanol, benzyl alcohol, lavandulol, 3-oxo-α-ionol, and hexadecanoic acid were predominant in the bound form. Odor activity values (OAV) and relative odor contribution (ROC) of free and glycosidically bound compounds were calculated. Thus, ethyl 3-methylbutanoate, methyl 2-methylbutanoate, methyl butanoate, 3-methyl-3-buten-1-ol, octan-1-ol, 3-methylbutanal, hexanal, 2-nonanone, 2-phenylethanol, and limonene showed OAV >1 after hydrolysis, contributing to the overall aroma. Results revealed that the bound fraction of jackfruit volatiles is eight times fold that their free counterpart. Information about the first research of glycosidically bound compounds in jackfruit released by enzymatic hydrolysis is provided. The results reinforce the importance of aroma precursors to suggest the raw material according to the applied pretreatment and thus take advantage of the aromatic potential that they can develop.