[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.

Antifatigue effects and antioxidant activity in polysaccharide fractions from Chinese yam bulbils.

Polysaccharides are the principal component in Chinese yam (Dioscorea opposita Thunb.) bulbils. The properties and antifatigue of polysaccharides from yam bulbils (PYB) were identified and compared. Their molecular weights (PYB-1 and PYB-2) were approximately 145 and 11 kDa, respectively, with active ß-configurations. Meanwhile, the antifatigue activities of PYBs were tested in mice via exhaustive swimming tests (EST). The EST results indicated that PYB-1 and PYB-2 significantly prolonged swimming time in mice (p < .05). Associated with this increase was a rise in hepatic glycogen content and antioxidant enzyme (superoxide dismutase (SOD), glutathione peroxidase (GSH-Px)) activity, along with a decline in blood urea nitrogen, lactic acid, and malondialdehyde levels. The results showed that molecular weight might contribute to the antifatigue effects of PYBs. Additionally, antioxidant tests showed that PYB-1 had stronger free-radical scavenging activity than PYB-2. Taken together, the findings indicated that PYBs exhibited effective antifatigue and antioxidant activities providing additional evidence supporting the use of PYBs as functional food ingredients for relieving fatigue.

Effects of sodium carboxymethyl cellulose on storage stability and qualities of different frozen dough.

Hydrocolloids as Additives have been used for improving the quality of frozen dough for a long time. In this work, the effects of sodium carboxymethyl cellulose (CMC) on quality changes of frozen dough in storage were studied. The water loss rate of the dough and water holding capacity were measured. Rheological and texture properties of the frozen dough were measured by a rheometer and a texture analyzer, respectively. Scanning electron microscopy (SEM) was used to characterize surface network structure and protein structure changes of the frozen dough. Our results reveal that the addition of CMC can inhibit the formation of ice crystals and recrystallization, thus effectively stabilizing the molecular structure of starch, and resulting in more uniform moisture distribution in the frozen dough. When 3% addition of CMC, the water holding capacity of the two kinds of dough reached the best, and the water loss rate of corn dough reached the lowest. The cohesion of the two kinds of dough reaches the maximum with 3 wt% addition of CMC, while the hardness and chewiness of wheat and corn multigrain dough reaches the maximum with 3 wt% and 4 wt% addition of CMC, respectively. The results show proper CMC addition (3 wt% and 4 wt%) finally improves the stability and qualities of the frozen dough. The research concerning the effects of CMC on quality of frozen dough provides better understanding for the frozen food industry.