Quantification of crocin, picrocrocin and safranal in saffron stigmas obtained from sounded corms with acoustic waves.

Introduction: Plant acoustic frequency technology (PAFT) is the effect or treatment of a plant with a specific frequency sound wave. Objective: The sound waves with different frequencies and a sound pressure level 77 dB were emitted on the saffron corms in a controlled environment using aeroponic cultivation and the contents of crocin, picrocrocin and safranal in their produced stigmas were analysed by high‐performance liquid chromatography. For this purpose, the corms were divided into two groups. In group 1, sound waves with the frequencies of 0.5, 1 and 2 kHz were emitted on saffron corms in different stages of sprouting, flowering and the whole stage of sprouting and flowering. In group 2, sonication was performed on the corms during the flowering stage at 4, 8, 12 and 16 kHz frequencies. Results: The changes in the contents of crocin, picrocrocin and safranal were not significantly compared to the control at 0.5, 1 and 2 kHz frequencies in the stages of sprouting and flowering of corms. While the higher frequencies (4, 8, 12 and 16 kHz) in flowering stage were affected significantly, the crocin and picrocrocin content increased 8.5% and 30%, applying the frequency of 12 and 8 kHz, respectively. Also, the effect of sound exposure time per day with the frequency of 16 kHz at 15, 30 and 60 min were investigated. Conclusion: The findings showed that the corms could be affected by sounding in the different stages of growth of the corm and also in the content of secondary metabolites. Sound waves with different frequencies were emitted on the saffron corms in a controlled environment using aeroponic cultivation. The findings showed the sound wave affected on the secondary metabolites content of their stigmas. The frequencies less than 2 kHz did not affect the content of secondary metabolites significantly. While, at the frequencies of 4‐16 kHz, the contents of secondary metabolites changed significantly. Moreover, the longer sounding time caused the more increase in the content of secondary metabolites happened. [ABSTRACT FROM AUTHOR]