Characterizing and Analyzing Volatile Organic Compounds in Wild Strawberries Using HS-SPME-GC-MS

A recent joint study between the Jiangsu Academy of Agricultural Sciences, the Zhongshan Biological Breeding Laboratory, and Nanjing Agricultural University (all in Nanjing, China) identified 126 volatile organic compounds (VOCs), which helps to determine the aroma of the fruit, in the ripe fruit of 22 cultivars from four wild strawberry species. Headspace solid-phase microextraction-gas chromatography–mass spectrometry (HS-SPME-GC–MS) was used in the identification process. A paper based on their research was published in Food Chemistry: X (1).

Cultivated strawberry (Fragaria × ananassa) are known for their large fruit, vibrant color, and strong antioxidant properties which are beneficial to human health. However, strawberries lack an intense aroma (2,3). Aroma is based on a complex mixture of various VOCs which not only endow a unique fragrance to the strawberry but also play a crucial role in the plant's ecological adaptability, such as pollinator attraction and pathogen defense (4,5). Researchers have identified over 979 VOCs in fresh strawberry over the past few decades (6,7) and have extensively studied the diversity of VOCs between wild and cultivated strawberries (8,9).

A powerful analytical technique used to detect volatile and semi-volatile compounds in complex samples (10), HS-SPME-GC–MS combines solid-phase microextraction (SPME) for sensitive and efficient VOC extraction from the headspace of a sample with gas chromatography (GC) for separation and mass spectrometry (MS) for detailed identification and quantification. The method offers high sensitivity, requires minimal sample preparation, and avoids the use of solvents, which makes it friendly to theenvironment (11). Due to its wide use in food, environmental, and biological sample analysis, HS-SPME-GC–MS is particularly useful for studying VOCs in complex matrices, with applications in flavor and fragrance analysis, environmental monitoring, and health research (12-14).

The study revealed that VOCs can serve as reliable biomarkers for differentiating wild strawberry species, identifying 60 potential markers through the application of multivariate statistical techniques. These findings establish a critical foundation for the use of volatile compounds in the identification and genetic improvement of strawberry species and provide insights that can inform breeding programs aimed at enhancing the flavor profiles of cultivated varieties (1).

The researchers believe that a major strength of the study lies in its comprehensive analysis of strawberry volatiles, which opens potential applications for flavor improvement in strawberry breeding and the food industry.

However, there are some limitations with this study, the authors wrote. This study lacked sensory evaluations to correlate VOCs with the perceived aroma, and the relatively small sample size may limit the generalizability of the findings. Moreover, the focus on ripe fruit excludes VOC variations across growth stages, which may be a significant factor in the overall volatile profile. Although 22 wild strawberry varieties were examined, the findings may not fully represent the diversity within the broader spectrum of wild strawberry species. Additionally, the analytical methods employed are effective, they may not capture all VOCs, especially those present at low concentrations or those with high volatility.

Furthermore, the study did not account for environmental factors or post-harvest processing effects on the VOC content, and VOCs were analyzed at a single time point. Therefore, future research should investigate the variations in VOCs across different stages of strawberry development while expanding the analysis to encompass a broader range of wild strawberry species and cultivars. Additionally, it is essential to explore the biosynthetic pathways of key VOCs to gain deeper insights into the genetic and environmental factors that influence aroma profiles (1).

Red large ripe strawberries close-up. © Sham-ann - stock.adobe.com

References

1. Xu, L.; Liu, W.; Pan, Z.; Pang, F.; Zhang, Y.; Liang, J.; Wang, Q.; Wang, J.; Zhao, M.; Qiao, Y.; Yuan, H. Characterization and Comparative Analysis of Volatile Organic Compounds in Four Aromatic Wild Strawberry Species using HS-SPME-GC-MS. Food Chem. X 2024, 25, 102092. DOI: 10.1016/j.fochx.2024.102092

2. Negri, A. S.; Allegra, D.; Simoni, L.; Rusconi, F.; Tonelli, C.; Espen, L.; Galbiati, M. Comparative Analysis of Fruit Aroma Patterns in the Domesticated Wild Strawberries “Profumata di Tortona” (F. moschata) and “Regina delle Valli”(F. vesca). Front. Plant Sci. 2015, 6, 56. DOI: 10.3389/fpls.2015.00056

3. Wang, J.; Cheng, Y.; Ma, C.; Ni, Y.; Yu, J.; Gao, H.; Sheng, L. Integrate Analysis of Metabolome and Transcriptome of Three Fragaria × ananassa Cultivars to Stablish the Non-Volatile Compounds of Strawberry flavor. LWT 2024, 198, 116043. DOI: 10.1016/j.lwt.2024.116043

4. Dudareva, N.; Klempien, A.; Muhlemann, J. K.; Kaplan, I. Biosynthesis, Function and Metabolic Engineering of Plant Volatile Organic Compounds. New Phytologist 2013, 198 (1), 16-32. DOI: 10.1111/nph.12145

5. Pan, L.; Huang, R.; Lu, Z.; Duan, W.; Sun, S.; Yan, L. et al. Combined Transcriptome and Metabolome Analysis Identifies Triterpenoid-Induced Defense Responses in Myzus persicae Sülzer-Infested Peach. Journal of Experimental Botany 2024, 75 (20), 6644-6662. DOI: 10.1093/jxb/erae339

6. Schwieterman, M. L.; Colquhoun, T. A.; Jaworski, E. A.; Bartoshuk, L. M.; Gilbert, J. L.; Tieman, D. et al(2014). Strawberry Flavor: Diverse Chemical Compositions, A Seasonal Influence, and Effects on Sensory Perception. PloS one 2014, 9 (2), e88446. DOI: 10.1371/journal.pone.0088446

7. Ulrich, D.; Kecke, S.; Olbricht, K. What Do We Know About the Chemistry of Strawberry Aroma? J. Agric. Food Chem 2018, 66 (13), 3291-3301. DOI: 10.1021/acs.jafc.8b01115

8. Drawert, F.; Tressl, R.; Staudt, G.; Köppler, H. Gaschromatographisch-massenspektrometrische Differenzierung von Erdbeerarten/Gaschromatographical-Masspectrometrical Differentiation of Aroma Substances from Strawberries. Zeitschrift für Naturforschung C, 1973, 28 (9-10), 488-493. DOI: 10.1515/znc-1973-9-1002

9. Ulrich, D.; Hoberg, E.; Rapp, A.; Kecke, S.Analysis of Strawberry Flavour–Discrimination of Aroma Types by Quantification of Volatile Compounds. Zeitschrift für Lebensmitteluntersuchung und-Forschung A 1997, 205, 218-223. DOI: 10.1007/s002170050154

10. Lancioni, C.; Castells, C.; Candal, R.; Tascon, M. Headspace Solid-Phase Microextraction: Fundamentals and Recent Advances. Advances in Sample Preparation 2022, 3, 100035. DOI: 10.1016/j.sampre.2022.100035

11. Azari, A.; Kamani, H.; Sarkhosh, M.; Vatankhah, N.; Yousefi, M.; Mahmoudi-Moghaddam, H. et al. Nectarine Core-Derived Magnetite Biochar for Ultrasound-Assisted Preconcentration of Polycyclic Aromatic Hydrocarbons (PAHs) in Tomato Paste: A Cost-Effective and Sustainable Approach. Food Chem. X 2024, 24, 101810. DOI: 10.1016/j.fochx.2024.101810

12. Azzi-Achkouty, S.; Estephan, N.; Ouaini, N.; Rutledge, D. N. Headspace Solid-Phase Microextraction for Wine Volatile Analysis. Critical Reviews in Food Science and Nutrition 2017, 57 (10), 2009-2020. DOI: 10.1080/10408398.2014.957379

13. Sadighara, P.; Abedini, A. H.; Mahvi, A. H.; Esrafili, A.; Mohammadi, A. A.; Tarahomi, A.; Yousefi, M. Benzo (a) pyrene in infant foods: A Systematic Review, Meta-Analysis, and Health Risk Assessment. Reviews on Environmental Health 2024, 39 (3), 531-537.DOI: 10.1515/reveh-2022-0263

14. Zhakupbekova, A.; Baimatova, N.; Kenessov, B. A Critical Review of Vacuum-Assisted Headspace Solid-Pphase Microextraction for Environmental Analysis. Trends in Environmental Analytical Chemistry 2019, 22, e00065. DOI: 10.1016/j.teac.2019.e00065