Identification and Quantitation of the Volatile Compounds Responsible for the Aroma of Pawpaw (Asimina triloba)

Abstract

The aim of this study was to perform an exhaustive analysis of the aroma active compounds in pawpaw fruit using gas chromatography-olfactometry (GC-O) on capillary GC columns with a variety of extraction techniques such as solid phase microextraction (SPME) and solvent extraction. The volatile extracts were obtained using headspace solid phase micro-extraction (HS-SPME) for 30 min at two temperatures (23°C and 50°C), and by solvent extraction with dichloromethane. The extracts were analyzed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). The SPME extraction at 50°C caused an increase in the levels of Strecker aldehydes (3-methyl butanal, methional, and phenylacetaldehyde). To eliminate potential artifacts, the study focused on SPME at 23°C and solvent extraction as the methods for characterization of the odor-active compounds in pawpaw. Forty-four odor active compounds were detected in the pawpaw fruit, including fifteen compounds that were identified in pawpaw for the first time. Some of the newly reported compounds, with high flavor dilution values include homofuraneol, eugenol, vanillin, acetaldehyde, diacetyl, gamma-octalactone and delta-octalactone. These high intensity odor active compounds, in combination with the many esters, contribute to give the sweet, creamy, mango, pineapple and banana-like character used to describe the flavor of pawpaw fruit. In addition, quantitation of these compounds was achieved in this study. These results provide new understanding into the volatile compounds responsible for the aroma of pawpaw fruit.