[Study on Subcritical Fluid Extraction of Essential Oil from Cinnamomum camphora and Its Antibacterial Activity].

Objective: To determine the optimum extract condition of essential oil from dry Cinnamomum camphora leaves and to study its antibacterial activity. Methods: The essential oil was extracted by subcritical fluid, and analyzed by response surface methodology based on single factor test. The chemical compositions of essential oil were analyzed by GC-MS, and the components were quantitatively determined by normalization method. The agar disc diffusion and dilution broth method were used to determine antibacterial activity. Results: The extraction rate was highest as 3. 54%,which matched with the predictive yield of 3. 56%,and the extraction time was30 min, the extraction temperature was 40 ℃,and resolution temperature was 65 ℃. 47 chemical constituents were identified and isolated from Cinnamomum camphora, which was analyzed by GC-MS. The main chemical constituents were eucalyptol( 24. 74%),bicyclo[3. 1. 0]hexan-4-methylene-1-( 1-methylethyl) ( 7. 05%),linalool( 5. 82%),caryophyllene ( 4. 75%). The essential oil from Cinnamomum camphora had different degrees of inhibition on Escherichia coli,Staphylococcus aureus, Pseudomonas aeruginosa,Bacillus subtilis. Conclusion: Subcritical fluid is suitable for the extraction of essential oil from Cinnamomum camphora and the essential oil has a good antimicrobial activity.

[Study on rapid non-destructive detection of the freshness of paddy based on NIRS].

A prediction model of paddy storage time was established based on near infrared reflectance (NIRS) and chemometrics. A spectroradiometer was used for collecting spectra in the wavelength range from 950 to 1 650 nm. The NIR spectra were collected from 90 samples of paddy. The best pretreatment method was obtained while choosing the total spectra area combined with PLS using the UNSCRAMBLER 9.7. The best pretreatment method is first derivative combined with S. Golay, and the number of principal components is 7. The model is feasible, because the r2 is 0.9679, RMSEP is 54.51 and the result of T-test is passable while validation method is cross validation In this paper, a feasible method is established to measure the storage time of paddy based on near infrared reflectance(NIRS)and chemometrics.