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In order to reveal the aroma compositions of two varieties of Yunnan teas processed based on the Liu Bao tea craft and to explore the more suitable varieties of tea plants for making Liu Bao tea, headspace solid-phase micro extraction and gas chromatography mass spectrometry (HS-SPME-GC/MS) was used to analyze the aroma compositions of two varieties of Yunnan teas by combining the relative odor activity value (ROAV) method with the relative odor activity value (ROAV) method. Headspace solid-phase micro extraction and gas chromatography mass spectrometry (HS-SPME-GC/MS) was used to analyze the volatile constituents of the two varieties of tea from Yunnan by using the relative aroma activity value (ROAV) method. The results showed that a total of 152 volatile components were detected, with alcohols and esters as the main volatile components, and linalool, lauryl alcohol, nonanal, dihydrokiwifruit lactone, methyl linolenate and methyl palmitate as the main volatile components, and the results of ROAV showed that there were 19 main aroma-contributing volatile components during the processing of the two varieties, and the aroma compounds that were significantly (P

In this study, the fresh leaves of Yun kang 10 with one bud and two or three leaves in spring, summer and autumn were used as raw materials. After anaerobic treatment, white tea was processed by the same process. The quality differences of white tea made from raw materials in three seasons after anaerobic treatment were explored by sensory evaluation, physical and chemical composition determination and UHPLC-MS/MS high-throughput detection technology to detect the content of amino acid components. The results showed that there were significant differences in the quality of white tea in the three seasons. The dry tea of white tea in spring was bright green in color. The aroma was strong, lasting, high and intensive, and had a variety of aroma types such as flowery, honey, tip aroma, medicinal and the fragrance of unique process. The taste was strong, fresh, sweet and brisk. The color of tea soup was bright yellow. Infused leaf was soft and bright. The quality of sensory was the best. The contents of amino acids, soluble sugar, caffeine, water extract and flavonoids of white tea were the highest in spring, and the content of tea polyphenols white tea was the highest in summer. A total of twenty amino acids were detected, of which 18 amino acids were significantly different (P

In order to study the key aroma compounds of Zijuan white tea with different processing technologies, headspace solid-phase micro extraction and gas chromatography mass spectrometry (HS-SPME-GC-MS), combined with sensory evaluation, PCA validation, OPLS-DA analysis and relative odor activity value (rOAV), was used to analyze and screen the key aroma compounds of Zijuan white tea. The results showed that 82 major aroma components were detected, mainly alcohols, esters, heterocyclic and aromatic compounds, with relatively high contents of linalool, methyl salicylate, benzyl alcohol and β-Ionone. The results of rOAV analysis showed that 9 volatile organic compounds including 1-octen-3-ol, α-Ionone, phenylacetaldehyde and methyl salicylate contributed to the aroma formation of natural withering Zijuan white tea (TZW) with floral and fruity aroma and spicy medicinal aroma, and 9 volatile organic compounds including 1-octen-3-ol, α-Ionone, β-Ionone and benzaldehyde contributed to the aroma formation of compound withering Zijuan white tea (CZW) with floral and fruity aroma and spicy aroma. OPLS-DA analysis combined with rOAV showed that 1-octene-3-ol and methyl salicylate were the key compounds for aroma difference between TZW and CZW. In summary, the flower and fruit aroma of Zijuan white tea processed by natural wilting was more abundant, which could effectively improve the aroma quality of Zijuan white tea.

In order to increase yield,take the Bacillus subtilis Asr as the expreession strain, the fermentation process of Bacillus subtilis Asr was optimized by orthogonal test and response surface method. The results show that three main factors affecting bacterial yield are leaching yeast powder, MgSO4 and CaCl2. The best fermentation medium formulation is as following: sucrose 20 g/L, peptone 10 g/L, leaching yeast powder 8.65 g/L, K2HPO4 3.0 g/L, MgSO4 0.27 g/L and CaCl2 0.53 g/L. The optimal culture conditions are as following: 37 ℃, initial pH 7.0, inoculum of 10% and stirring speed of 250 r/min. After the optimization, the highest yield of Bacillus subtilis Asr reaches 7.30×108 cfu/mL, which is 3.95 times higher than that before optimization. The study provides a technical reference for the subsequent bacterial scale-up culture in fermentor and the optimization of fermentation medium from other Bacillus subtilis.

Collagen of type Ⅱ is the major component of hyaline cartilage in animals. Based on its biocompatibility, biodegradability and many other biological properties, for example promoting cell growth and differentiation, collagen of type Ⅱ has been widely applied in various fields, such as tissue engineering material, food, cosmetic, packaging, etc.. In recent years, using genetic engineering to produce recombinant collagen of type Ⅱ is popular. The structure, function and application of collagen of type Ⅱ are described, the latest research progress for producing recombinant collagen of type Ⅱ by genetic engineering is put forward, and the large-scale production of hydroxylated collagen in E.coli in the future is previewed, which would be helpful for the further development and study of collagen of type Ⅱ.

As a kind of green and healthy microecologics, Bacillus subtilis could balance the intestinal flora, promote the nutrient absorption and enhance immunity. Microecologics is one of the ideal antibiotics alternative, which are effective in preventing and treating animal disease and promoting the growth and development of the animal. Because of its advantages, such as no toxin side effect and no residual or drug-resistant, microecologics has been used in livestock breeding widely. Here, we concluded the characteristics and mechanism of Bacillus subtilis,elaborated application of microecologics on livestock breeding, discussed its problems and suggested its solved methods. In the end, the future of microecologics was expected in order to provide a reference for subsequent livestock breeding.

Once damaged, articular cartilage should be repaired or replaced owing to its limited self-repair capacity. But traditional methods for treating cartilage defect are not satisfying. In contrast, tissue engineering offers promising hope for cartilage disease. In the three main factors of tissue engineering, such as seed cells, scallfold materials and signal molecules, scallfold materials play a fundamental role. The paper reviews cartilage scallfold materials, introduces collagen type Ⅱ, hyaluronic acid and chondroitin sulfate which naturally exist in cartilage, and dicusses the current problems and the future directions of tissue engineering scallfold.