Zheng Fuping

Identification of volatile components in Chinese Sinkiang fermented camel milk using SAFE, SDE, and HS-SPME-GC/MS.

The volatile components of Chinese Sinkiang fermented camel milk were isolated by solvent assisted flavour evaporation (SAFE), simultaneous distillation extraction (SDE, dichloromethane and diethyl ether as solvent, respectively) and headspace solid-phase microextraction (HS-SPME, CAR/PDMS, PDMS/DVB and DVB/CAR/PDMS fibre extraction, respectively) and analysed by GC/MS. A total of 133 volatile components were identified under 6 different conditions, including 30 esters, 20 acids, 18 saturated alcohols, 15 unsaturated aliphatic alcohols, 8 saturated ketones, 9 saturated aldehydes, 8 unsaturated aliphatic aldehydes, 6 furans, 5 sulphur-containing compounds, 5 ethers, 5 lactones, 3 other compounds, and 1 unsaturated aliphatic ketone. Three pretreatment methods were compared, assisted by principal component analysis (PCA). The results indicated that the volatile components obtained using different methods varied greatly both in categories and in content, and therefore, a multi-pretreatment method should be adopted together with GC/MS. A total of 71 aroma-active compounds were detected by gas chromatography-olfactometry (GC-O), among which 66 aroma-active compounds were found by SDE (60, dichloromethane as solvent; 24, diethyl ether as solvent), 26 by SAFE.

Epoxidation of β-pinene to 2,10-epoxypinane by Oxone

This paper describes a highly effective catalytic method for epoxidation of β-pinene to 2,10-epoxypinane using potassium peroxomonosulfate (Oxone) as oxidant and acetone as catalyst. Structure of 2,10-epoxypinane was characterized by data of infrared spectrum, GC-MS spectrum and 1H NMR spectrum. The procedure consists simply in stirring the substrate, NaHCO3 and acetone, at 0°C, with dropwise addition of an aqueous solution of Oxone. Optimization of the conditions identified (1) the mole ratio of Oxone to β-pinene 0.8:1, (2) reaction temperature 40°C, (3) pH 7.0–7.5, and (4) reaction time 2.5h. The yield of 2,10-epoxypinane can reach 85.4% and the system exhibits good chemical selectivity and few byproducts.