Public Perception and Odor-causing Compound Analysis of Negative Odors from Ginkgo biloba Seeds

This study aims to clarify the public perception characteristics and influencing factors of the negative odor emitted by Ginkgo biloba seeds, and reveal the key odor-causing substances and their release patterns at different developmental stages and under damaged conditions. A questionnaire survey was conducted in 5 ginkgo landscape sites in Beijing (n = 454). Meanwhile, intact and damaged G. biloba seeds at four developmental stages — green fruit (S0), non-wrinkled fruit (S1), slightly wrinkled fruit (S2) and severely wrinkled fruit (S3) — were selected as test materials. The key odor-causing substances were screened via headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with relative odor activity value (ROAV) and orthogonal partial least squares discriminant analysis (OPLS-DA).

The results showed that the dominance, occurrence frequency and perceived concentration of the negative odor were all significantly negatively correlated with olfactory satisfaction, and the olfactory experience score exerted a greater influence on overall landscape satisfaction than the visual score. A total of 13 volatile compounds were identified, among which butyric acid, hexanoic acid, methyl butyrate and methyl hexanoate were the key differential compounds (variable importance in projection, VIP > 1), with their absolute contents in damaged seeds significantly higher than those in intact seeds. From the slightly wrinkled stage to the severely wrinkled stage, the absolute content of acidic compounds accounted for over 74% of the total volatiles, and butyric acid was the core odor contributor with the highest ROAV. Butyric acid and hexanoic acid are the core odor-causing components of the negative odor from G. biloba seeds, and the massive release of acidic substances after seed damage at maturity is the main cause of public olfactory discomfort.