Time filter

Source Type

Ma X.,Shanghai Institute of Technology | Ma X.,Anhui Key Laboratory of Tobacco Chemistry China Tobacco Anhui Industrial Co. | Li L.,Shanghai Institute of Technology | Zhang M.,Shanghai Institute of Technology | Yu H.,Shanghai Institute of Technology
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering

In order to obtain non-cytotoxic hydrogel of superior water holding capacity and biocompatibility, this paper reported about the production of pH-sensitive hydrogels at different gamma poly glutamic acid (γ-glutamic acid, γ-PGA)/polyvinyl alcohol (PVA) mass radios of 3:7, 4:6, 5:5, 6:4 and 7:3 with no use of any chemical reagents. Then the properties and structure of the prepared hydrogels were characterized and the swelling kinetics of the different feed composition in different pH value (pH values of 4.0, 7.4 and 9.0)solutions were studied. The preliminary research on the drug slow-release of the prepared hydrogels were also conducted. The results showed that the γ-PGA/PVA hydrogels have the pH sensitivity and swelling-deswelling properties. With the amount of γ-PGA increasing, the swelling degree would decrease and hydrogels would show higher endurance of heat. Meanwhile, since the hydrogen bonds between γ-PGA and PVA were enhanced, the structure of the hydrogel would become more compact which would hinder the diffusion of water in the hydrogel and lead to the enhancement of its water-retention rate. The kinetic studies showed that the different pH values of solution had no effect on the initial diffusion behavior of the hydrogel which all belong to the non-Fickian diffusion model. It was also proved that different hydrogel samples in different pH values shared the same change trend of swelling rate which indicated that in the initial swelling process of γ-PGA/PVA hydrogel, the diffusion rates of water molecules and the relaxation rate of macromolecules were almost the same which also indicated that hydrogel with different components shared the same swelling kinetics process. In the same pH value environment, the water diffusion coefficient would increase along with the increase of hydrogel swelling rate, the value of characteristic constant would increase with the increasing content of PVA. The drug release study showed that 5 groups of hydrogel samples of drug embedding effect was more ideal and the embedding rates were between 70%-80%. The changes of pH value had consistent effects on the release properties of 5 groups samples. The hydrogel released rapidly in the buffer solution of pH value 7.4 with release rate of about 80%, and the release period of the buffer solution in pH value 1.2 was lengthened with final release rate of about 40%. With the increase of PGA content and the decrease of PVA content, the release rate of the drug decreased along with a lower final equilibrium release percentage and a longer release period. In addition, it was found that the drug embedding rate of the 5 groups of hydrogel samples was higher, and the performance was satisfactory. This may be due to the structure of the hydrogel containing carboxyl group, which belongs to pH sensitive hydrogel and the hydrogel in an acidic medium swelling rate and swelling degree smaller than in alkaline medium. The results provide a reference in the application of biotechnology, medical and industrial. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved. Source

Tian Z.,China Tobacco Anhui Industrial Co. | Chen C.,China Tobacco Anhui Industrial Co. | Xu Z.,China Tobacco Anhui Industrial Co. | Zhou S.,China Tobacco Anhui Industrial Co. | And 5 more authors.
Acta Tabacaria Sinica

Effects of cutting width and drying process on burning temperature, mainstream smoke (MMS) and sensory quality of slim cigarettes were investigated. Relationship between chemical components in MMS and burning temperature was discussed. Results showed that steam-heated cylinder drier (KLD) was better as for sensory quality than high expansion lamina dryer (HXD). Small cutting width resulted in a rise in burning temperature, tar and hazard index, as well as an increase in the aroma quantity and sensory satisfaction. © 2015, Acta Tabacaria Sinica Editorial Department. All right reserved. Source

He Q.,Anhui Key Laboratory of Tobacco Chemistry China Tobacco Anhui Industrial Co. | He Q.,China Tobacco Anhui Industrial Co. | Zhang Y.,China Tobacco Anhui Industrial Co. | Zhou S.,Anhui Key Laboratory of Tobacco Chemistry China Tobacco Anhui Industrial Co. | And 8 more authors.
Flavour and Fragrance Journal

Glycosidically bound aroma compounds in flue-cured tobacco were estimated by capillary gas chromatography-mass spectrometry (GC-MS). After a fast isolation of extracts obtained by HP-20 solid-phase extraction and methanol elution, glycosides were treated with enzymatic hydrolysis and trifluoroacetylation (TFA) before GC-MS analysis. A totall of 21 bound aglycones, mainly consisting of aliphatic alcohol, aromatic components, C13-norisoprenoids, sesquiterpenoids and polyphenols, were identified by enzymatic hydrolysis. In addition, with the aid of enzymatic hydrolysis, 14 glucosides, one rutinoside and three vicianosides were identified by TFA derivatization. The three vicianosides were identified for the first time in flue-cured tobacco. The norisoprenoids group made up >40% of the total level of aglycons in ripe tobacco, followed by polyphenol and aromatic derivatives (27 and 19%, respectively). Generally, levels of bound compounds increased significantly and the content of total glycosides increased by 36% with maturation. Among the glycosides detected, 3-oxo-α-ionol-glucoside was the most sensitive to maturity and increased the maximum degree. © 2015 John Wiley & Sons, Ltd. Source

Discover hidden collaborations