2 nonanone

LDPE film with a thickness of 47.76 μm, and a density of 0.923 g/cm³ was donated by Tianjin Baihao Co., Ltd. (Tianjin, China). The chemical reagents used and their corresponding purity, and CAS numbers were as follows: D-limonene (D-LE, 99%, 5989-27-5) from Adamas (Innochem, Beijing China); myrcene (ME, 99%, 123-35-3) from Aladdin (Shanghai Aladdin Biochem. Tech., Shanghai, China); ethyl hexanoate (EH, 99%, 123-66-0) from TCI (J&K Chemical, Beijing, China); 2-nonanone (2-NO, 99%, 821-55-6), and linalool (LO, 98%, 78-70-6) from Macklin (Tianjin Sanjiang, Tianjin, China); anhydrous ethanol (99%, 64-17-5) and n-hexane (99%, 110-54-3) from Jiangtian (Tianjin Jiangtian, Tianjin, China). D-limonene, myrcene, ethyl hexanoate, 2-nonanone, and linalool were selected as volatile flavor molecules in liquid foods, such as fruit juice and liquor [30 (link),31 (link)], and 10% (V/V) aqueous ethanol solution was selected as the food simulation solution.

Headspace solid phase microextraction was used to sample volatiles of tomatoes according to a previous method [22 (link)]. Ten fruits were ground together using a mill (A11, IKA, Germany). These samples were split into three aliquots and all replicates of 5 g were processed using following methods. The samples were added with 1 g of sodium chloride, containing 10 μL of 2-nonanone (internal standard; dilute 5 × 10³ times; Macklin, China) in a 20 mL vial. Volatiles were collected using a 1cm DVB/CAR/PDMS Stable Flex fiber (50/30 μm; Supelco, PA, USA) in a 50 °C water bath for 30 min after a 50 °C equilibration for 15 min. Afterwards, the analysis was performed on a 320-MS gas chromatography-mass spectrometer (GC-MS, Bruker, Germany) with a BR-5 ms column (30 m × 0.25 mm ID × 0.25 μm). The program of GC-MS was set according to a previous method [22 (link)]. Chromatographic profiles of volatiles were identified using spectral library comparison (NIST standard library). The relative content of the compound referred to the internal standard and expressed as mg kg⁻¹ fresh weight.

D(+)-Camphor (98% purity, CAS No: 464-49-3) used as internal standard, perilla ketone (CAS No: 553-84-4), dihydroartemisinic acid (CAS No: 85031-59-0) and artemisinin (CAS No: 63968-64-9) standards were purchased from Shanghai Yuanye Biotechnology Co. LTD (Shanghai, China). The isoegoma ketone (CAS No: 34348-59-9) and raspberry ketone (CAS No: 5471-51-2) standard was purchased from Chengdu DeSiTe Biological Technology Co., Ltd (Chengdu, China). β-Caryophyllene (CAS No: 87-44-5) was purchased from Beijing Solarbio Science & Technology Co.,Ltd (Beijing, China). (+)-Pulegone (CAS No: 89-82-7) and (-)-menthone (CAS No: 14073-97-3) standards were purchased from Sigma-Aldrich (Shanghai, China). (+)-Isomenthone (CAS No: 1196-31-2), 3-nonen-2-one (CAS No: 14309-57-0), 2-nonanone (CAS No: 821-55-6) standards were purchased from Shanghai Macklin Biochemical Technology Co., Ltd (Shanghai, China). Artemisinic acid (CAS No: 80286-58-4) was purchased from Chengdu Biochem Pure Biotechnology Co., LTD (Chengdu, China). 4-hydroxybenzalacetone (CAS No: 22214-30-8) standard was purchased from Nantong Feiyu Biotechnology Co., LTD (Nantong, China).