不同窖龄黄水的差异性及其对酒质影响的研究

分别以不同窖龄的黄水为研究对象,采用常规实验室方法和色谱分析技术对不同黄水进行分析,并在模拟条件下,研究不同黄水对酒质的影响。结果表明,300年窖龄黄水的总酸、总酯含量明显高于其他黄水,淀粉、还原糖利用率较高,微生物数量也明显较多。模拟实验结果表明糟醅受300年窖龄黄水的影响,发酵结果最好。     

Detection of alkaline phosphatase by competitive indirect ELISA using immunoglobulin in yolk (IgY) specific against bovine milk alkaline phosphatase

Immunoglobulin in yolk (IgY) (with a titer of 1.3 × 10⁶) specific against bovine milk (BM) alkaline phosphatase (ALP) was obtained by intramuscularly immunizing hens on the thigh and was used as the primary antibody to conduct competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) to determine BMALP in ALPs from BM and Escherichia coli sources. A relationship between the ELISA value and the BMALP level (0.01–10 μg/mL) in whole milk (R² = 0.9019) or in skimmed milk (R² = 0.9402) was observed. The maximal inhibition (%) of BMALP on the microtiter plate by free BMALP at 10 μg/mL whole milk (3.89 mU/μg BMALP) was about 50%, while no inhibition (%) of BMALP by free E. coli ALP at concentrations between 0.01 to 10 μg/mL (60 mU/μg E. coli ALP) was determined. At BMALP levels higher than 0.1 μg/mL, CI-ELISA was proved to be effective in differentiating between BMALP and E. coli ALP and quantifying BMALP in whole milk or skimmed milk in the presence of E. coli ALP with an activity of 0.6 U/mL. Higher inhibition (about 70%) of BMALP on the microtiter plate by free BMALP in diluted (10¹–10⁴ fold) milk samples was observed. The optimal conditions for CI-ELISA in determining BMALP (0.1–10 μg/mL) from ALPs in milk samples were using 10³-fold diluted crude IgY specific against BMALP as primary antibody and 10³-fold diluted goat anti-chicken IgG–ALP conjugate as the secondary antibody.     

Study on antibacterial properties and major bioactive constituents of Chinese water chestnut (Eleocharis dulcis) peels extracts/fractions

Recently, considerable attention has been paid to the biologically active of fruit and vegetable processing wastes. In this study, antibacterial properties and major bioactive constituents of Chinese water chestnut peels (CWCP) extracts and fractions were evaluated. The data displayed that ethyl acetate fractions (EF) from CWCP showed greater antibacterial activity than n-butanol fractions, methanol extracts and water fractions against three common foodborne pathogenic bacteria (Staphylococcus aureus, Escherichia coli and Listeria monocytogenes) assessed by the inhibition zone, minimal inhibition concentration and minimal bactericidal concentration values. In accordance with disc diffusion assay, S. aureus was more susceptible to EF than the other two pathogens. Furthermore, action-mode studies indicated that EF exhibited significant bactericidal activity against S. aureus by degrading and disrupting the cell wall and cytoplasmic membrane, ultimately the leakage of cell contents led to cell death. Finally, high-performance liquid chromatography coupled with photodiode array and electrospray ionization mass spectrometry was used for characterization of bioactive constituents in EF, and ten flavonoids aglycons were identified or tentatively identified. The results suggest that the extracts and fractions from CWCP could be potentially used as a possible food supplement to improve food safety by the control or elimination of foodborne pathogenic bacteria.     

Simultaneous Detection and Differentiation of Campylobacter jejuni, C. coli, and C. lari in Chickens Using a Multiplex Real-Time PCR Assay

A multiplex real-time PCR (qPCR) assay was developed for simultaneous detection and differentiation of the three most important Campylobacter species in chickens. Three novel sets of PCR primers and TaqMan probes were designed to amplify the unique DNA sequences within the hipO, cdtA, and pepT genes which are specific to Campylobacter jejuni, Campylobacter coli, and Campylobacter lari, respectively. To avoid competition in the multiple target amplifications, the concentrations of primers and probes were optimized. By using the optimized qPCR conditions together with a minor-groove binding probe of pepT, amplification efficiency greater than 92% and detection sensitivity of 38 genome copies/reaction have been achieved for all three targets. The assay was highly specific for C. jejuni, C. coli, and C. lari with testing of 33 Campylobacter strains and 20 non-Campylobacter strains. In chicken samples spiked with known quantities of Campylobacter cells, the assay was able to detect 1 CFU/g after a 24-h enrichment. Application of the assay in food was further evaluated using 21 fresh chicken samples obtained from local supermarkets. The results revealed that, after a 24-h or 48-h enrichment, 14 samples (66.7%) were positive for C. jejuni, five samples (23.8%) were positive for C. coli, and none of the samples was contaminated by C. lari. Taken together, the multiplex qPCR assay combined with an enrichment step is a sensitive, species-specific, and non-labor-intensive method suitable for rapid detection of C. jejuni, C. coli, and C. lari in chicken samples.     

黄连花茶加工工艺及其抗氧化作用研究

以黄连的花薹为原料,研究了黄连花茶的加工工艺及其抗氧化活性。结果表明,黄连花薹经杀青、冷却后,干燥,包装制得的黄连花茶风味清香、复水性好。采用霍恩氏法,对花茶的急性毒性(LD50)进行测定,21.5g/kg·BW剂量下,实验动物未发现死亡及异常;大于15g/kg·BW剂量,属无毒。水浸出物对羟自由基(·OH)和过氧化氢(H2O2)均具有清除作用。     

Autonomously replicating plasmid transforms Sorangium cellulosum So ce90 and induces expression of green fluorescent protein

A recombinant plasmid, pRP-GFP, harboring the green fluorescent protein (GFP) gene from the broad-host-range mobilizable plasmid pRK415 of the RK2 family was constructed and transferred by conjugation from Escherichia coli S17-1 to Sorangium cellulosum So ce90. The results of Southern blot analysis showed that the plasmid replicated autonomously without being integrated into the chromosome of the bacterium. In pRP-GFP, gfp was driven by a So ce90 DNA fragment called EpoPro, which is an 890-bp DNA segment spanning from -890 to -1 relative to the start codon (GTG) of epoA, a gene that encodes EPOS A, which is presumed to be involved in the initiation of epothilone biosynthesis. The GFP in the transformed S. cellulosum So ce90 was detected by fluorescence microscopy, which suggests that the EpoPro fragment had the function of promoter. Because the green fluorescent bacilli could be directly observed by fluorescence microscopy, the stable expression of GFP was rapid and convenient for conjugation screening in addition to the antibiotic resistance genes within the constructed plasmid. This is the first report on an exogenous plasmid that can be stably maintained as an extrachromosomal element in S. cellulosum.     

葛根软糖的研制

以葛根粉为主要原料,通过对比试验对凝胶剂进行最佳选择,结果表明选择琼脂作为凝胶剂口感最佳。通过正交试验确定产品的最佳配方为:葛根粉8g,淀粉糖浆120g,白砂糖40g,琼脂2%,柠檬酸0.3g,柠檬酸钠0.1g;在40℃下干燥(24～30)h后,所得软糖具有良好的咀嚼性及口感,综合品质良好。     

含氟复鞣剂研究进展

含氟复鞣剂可以赋予皮革良好的手感、优异的透气性、抗水抗油性、抗污性等性能。阐述了合成含氟复鞣剂用含氟单体和非氟共聚单体的选择及其合成工艺 ,介绍了含氟复鞣剂的研究进展 ,指出含氟复鞣剂今后将会向着高质量、多功能化方向发展     

意大利设计师Marco Maran及其作品

通过对意大利著名家具设计师Marco Maran生平、设计理念以及最新设计作品的分析,指出设计师只有热爱生活,并将技术、艺术和生活完美结合,才能成就优秀的设计,并希望中国年轻年设计师能从中得到启示。     

羊肉烤制品软罐头的研制

羊肉烤制品的质量受到工艺条件 影响,其中腌制,上色,焙烽,杀菌等关键工艺对其影响较大,通过大量试验结果表明采用低盐腌制,趁热上色,分段焙烤,高压杀菌等工艺可以使产品外观金黄油润,肉质细嫩而富有弹性,咸淡适口,味道鲜美,风味浓厚。