OPTIMIZATION OF THE NON-INVASIVE AND NON-DESTRUCTIVE EXTRACTION PROCESS AND ANALYSIS OF PAPAYA VOLATILE METABOLITES USING SPME-GC-MS

The analysis of volatiles is an alternative in the routine of quality control of fruits, since the volatile metabolites can change in the presence of microorganisms. A well-established method for extracting volatiles is the solid phase microextraction (SPME). This work aims to define some parameters (fiber coating, conditioning time and fiber exposure time) for an effective extraction. Whole papaya was inserted into a hermetically closed glass bottle and the system was left in conditioning for the volatiles accumulation. Then, extraction by SPME and subsequent desorption in a gas chromatograph was performed. Two fibers were evaluated: a 100 µm polydimethylsiloxane (PDMS) and a 65 µm polydimethylsiloxane/divinylbenzene (PDMS/DVB). The PDMS/DVB fiber extracted the highest number of volatiles. Central composite design (CCD) was performed to assess the effect of papaya conditioning time and the fiber exposure time on the response: number of detectable peaks. Both variables studied and their interactions were significant for the response. ANOVA showed that the quadratic terms and the lack of fit were not significant (p <0.05). A conditioning time of 10 min and exposure time of 30 min was sufficient for the detection of more than 100 compounds.

Keywords:
central composite design; response surface methodology; metabolomics; fruit