# Solid-Phase Microextraction Techniques and Application in Food and Horticultural Crops
## 3 Flavors and Aromas (Volatile Organic Compounds) in Foods Using HS-SPME
### Volatile Organic Compounds in Fruit/Fruit Juice  
[PERSON] et al. investigated the changes in the profile of volatile compounds as a function of aging in fresh pineapple juice under conditions of accelerated aging over a 16 week period at 25 \({}^{\circ}\)C [32]. For GC-MS analysis, samples were prepared using a 65 \(\upmu\)m PDMS/DVB SPME fiber, with an extraction time of 60 min at 40 \({}^{\circ}\)C. They proposed that Maillard reaction products, 4-hydroxy-2,5-dimethyl-3(2H) furanone and 4-methoxy-2,5-dimethyl-3(2H)-furanone could be used as marker compounds to monitor the aging profile of pineapple juice.  
[PERSON] et al. used headspace solid-phase microextraction (HS-SMPE) to extract aroma compounds from whole bananas and banana pulp [33]. A 50/30 \(\upmu\)m DVB/CAR/PDMS SMPE fiber was used together with a response surface methodology to optimize the extraction of these compounds. They found that the extraction temperature did not significantly affect extraction so it was set at 25 \({}^{\circ}\)C for the optimization process. Fiber exposure and headspace equilibrium times were modeled to determine optimum extraction conditions (whole bananas: 140 min equilibrium and 120 min exposure; banana pulp: 15 min equilibrium and 60 min exposure). Whole bananas and banana pulp had similar volatile profiles mainly consisting of esters. Aromas from green fruit pulp mainly contained acids and aldehydes while in those from whole fruit, terpen were mainly observed.  
Recently, [PERSON] et al. reported on the use of HS-SPME and GC-MS to profile mango cultivars using principle component analysis and the volatile organic profile data from each cultivar [34]. Here, 17 different mango cultivars were analyzed with 59 volatile organic compounds detected. These mainly consisted of monoterpenes (e.g., \(\alpha\)-pinene, \(\alpha\)-limonene, camphene, \(\gamma\)-terpinene, etc.) and sesquiterpenes (e.g., germacrene-D, \(\alpha\)-copaene, valencene, allaromadendrene, etc.), together with a smaller number of other types of compounds. Extraction was performed using 50/30 \(\upmu\)m of DVB/CAR/PDMS SPME fiber at 50 \({}^{\circ}\)C for 60 s, stirring at a rate of 60 rpm. A desorption time of 60 s and a desorption temperature of 230 \({}^{\circ}\)C were used. Principle component analysis using the volatile compound analysis data divided the cultivars into four distinct groups.  
[PERSON] et al. developed a HS-SMPE GC-MS method to detect volatile compounds in jabuticaba fruit (_Mycriaria jabuticaba_), a small grape-like fruit native to Brazil [35]. In total, 71 compound were extracted and identified. Both a 85 \(\upmu\)m CAR/PDMS and a 50/30 \(\upmu\)m DVB/CAR/PDMS SMPE fiber were used for the extraction of volatile organic compounds. The 85 \(\upmu\)m CAR/PDMS SMPE fiber provided better extraction, with a greater number of volatile organic compounds being detected. A response surface methodology was used to optimize extraction conditions. The most effective extraction occurred using an extraction time of 30 min at 42 \({}^{\circ}\)C, with 5% NaCl. The main compounds extracted were 1,3-dichlorobenzene 9.7%, esters ethyl (E)-2-butenoate 2.5% and ethyl acetate 10.7%, and terpenoids cyanophyllene 5%, eucalypt 5.8%, \(\beta\)-guaieene 2.9%, limonene 17.7%, colimene 3.6%, \(\alpha\)-pinene 2.2%, and \(\beta\)-pinene 3.0% (Figure 5).  
The two volatile compounds with the highest concentrations were limonene 17.7% and ethyl acetate 10.7%.