微生物传感器是以活体微生物细胞为感应元件,感应需要测定的靶标物质浓度并按照一定规律转换为可识别信号的检测装置.早期的微生物传感器以微生物测定和微生物电极的形式出现,近年来随着分子生物学和合成生物学技术的进步,基因工程类微生物传感器迅速发展,并且由于其成本低、使用便捷、功能扩展性强等优势,使其在食品安全领域具有良好的应用潜力.本文介绍了微生物传感器的发展历程和基本原理,总结了微生物传感器在食品安全检测、食品品质分析、食品安全毒性评估、食品污染脱毒等方面的最新研究成果,分析了微生物传感器发展趋势和当前的技术瓶颈.本综述可为食品安全快速检测技术研究和应用人员提供信息和技术参考,推动微生物传感器领域的进一步发展.

Imperation analogs have the furanocoumarin skeleton, with the isopentenyl group, which displayed significant bioactivities. The biotransformation of furanocoumarins imperation, isoimperation and phellopterin (1-3) by fungi has been proved to be an efficient method for the structural modification. Ten transformed furanocoumarin analogs were obtained by fungal biotransformation, including one new highly oxygenated furanocoumarin (4c). Aspergillus niger AS 3.739 displayed selectively transformed capability toward furanocouamrins (1-3) with one or two major products. So, seven hydroxylation and hydrolysis derivatives have been prepared efficiently. Additionally, the biotransformation of phellopterin gave multiple products (4a, 4b, 4c) by Cunninghamella blakesleana AS 3.970. The biotransformation time-courses of furanocoumarins have been established, which suggested the preferred incubation time. The bioactivities of furanocoumarin analogs have been investigated in an in vitro bioassay. And, furanocoumarins 1-3, 2a, and 2c displayed moderate anti-osteoporosis activities using MCET3-E1 cell line at the concentrations of 1, 10, and 100 mu M.

探究了彩麦麸皮花色苷在外界条件下的稳定性,为彩麦麸皮花色苷的加工应用提供理论参考,并加快相关产品的研究与开发.选取河南彩色小麦中普黑麦1号和漯珍6号蓝麦为原材料,利用紫外可见分光光度法研究了pH、温度、金属离子及VC等几种添加剂对彩麦麸皮花色苷的影响作用.结果表明:彩麦麸皮花色苷在偏酸性和低温(≤65℃)条件下较稳定.离子浓度为2.0 mmol/L时,K+、Na+和Ca2+的加入增强了花色苷的稳定性;Fe3+、Cu2+、VC及一定浓度的柠檬酸(≥0.5％)和蔗糖(≥55％)的加入则使花色苷稳定性下降;2％或3％的食盐可显著提高其稳定性.故彩麦麸皮花色苷的稳定性受pH和温度的影响较大,不同的金属离子和添加剂对其稳定性影响不同.

通过静态吸附解吸试验从12种树脂中优选出聚酰胺树脂,其吸附率为38.20%、吸附量为43.93 mg/g,解吸率73.22%,综合吸附解吸效率最高。聚酰胺树脂动态吸附解吸试验结果表明,在提取液上样量50 mL、上样液浓度4.37 mg/mL、上样pH值6.0、上样流速1.0 mL/min、水洗体积5倍、80%乙醇5倍体积洗脱、洗脱流速1.0 mL/min的最佳条件下,金花葵花总黄酮纯度可达到72.6%,产品具有很大的开发潜力。

In order to study the effect of the germination wheat flour onβ–xylosidase enzyme and arabinoxylan(AX),germinate wheat flour(including B flour and M flour )as raw material, the contents of AX and theirβ–xylosidase activities were determined respectively,the effects of germinationon dough rheology properties were studied ,and the correlation with flour physicochemical was analyzed. The results showed that with extending the time of wheat germination,the activities ofβ–xylosidase increased first and then decreased;the contents of water extractable arabinoxylan (WE–AX)gradually increased with the increase of the germination period,and the water unextractable arabinoxylan(WU–AX)contents were reduced,while the total AX contents showed a slight downward trend. With the time of germination increasing,the resistance to stretching of dough decreased and B flour below the M flour.β–xylosidase activity,WE–AX content,and extensibility were positively correlated with germination time,while total AX content,WU–AX content,ash content,resistance to stretching had negative correlation(ρ<0.01);dough extensibility was positively correlated withβ–xylosidase activity,and total AX,WU–AX,flour yield,resistance to stretching were significantly negatively correlated(ρ<0.01).

A functional solid beverage is developed in this paper by using barley grass powder as the main raw material,wheat germ powder,corn flour,glutinous rice flour,sesame seeds,isomalto-oligo saccharide as accessories. The beverage produced can improve human immunity,reduce blood sugar and protect liver. Through the single factor experiment,sensory evaluation indicated the suitable addition of barley grass powder,wheat germ powder,glutinous rice flour,corn flour,sesame seeds and isomalto-oligo saccharide. By orthogonal experiment,the influence of main raw materials on the sensory quality of product was studied. The result is that when the addition of barley grass powder,wheat germ powder,corn flour,glutinous rice flour,sesame seeds and isomalto-oligo saccharide were 30%, 5%,20%,13%,6% and 26% respectively,the product was obtained with the best texture and flavor. Drinking after by hot water brewing,the product had a suitable mellow taste and grain aroma with a certain health-care function.

介绍了HACCP体系在谷物固体饮料生产中的应用,对谷物固体饮料生产过程中各个环节进行了分析,确定了谷物固体饮料生产中的3个关键控制点及其关键限值,以期达到促进谷物固体饮料的生产和提升产品品质,保证产品安全的目的.

褐藻胶作为海洋植物提取物,近年来受到开发海洋类药物的研究人员关注.有报道称褐藻胶降解物具有治愈Ⅱ型糖尿病鼠的功效.基于此,本研究通过体外α-葡萄糖苷酶体系来探讨褐藻酸降解物的降血糖机制.结果表明:聚甘露糖醛酸片段(PM)和聚古洛糖醛酸片段(PG)对α-葡萄糖苷酶的活性均产生抑制作用,且其活性差异较大.其中具有明显抑制作用的PM的抑制类型属于混合型抑制,其抑制常数Ki和抑制率的IC50值仅分别为葡萄糖的4.4倍和7.0倍.通过比较PM、葡萄糖、甘露糖、果糖的Ki值和IC50值的差异,从构效关系上探讨α-葡萄糖苷酶与α-葡萄糖苷酶抑制剂的关系.

以小麦粉为研究对象,探讨了反应温度、反应pH值和底物浓度对小麦内源性β-木糖苷酶(EC.3.2.1.37)活性的影响.在单因素实验的基础上,采用三因素三水平的正交方法,分析各个因素对β-木糖苷酶活性测定的影响,并对测定条件进行优化.所得最佳测定条件为:反应温度60℃、pH4.6、底物浓度14 mmol/L.在此条件下,β-木糖苷酶活性为124.385 U/kg.

Enzyme activities of the endogenousβ-xylosidase in wheat bran were investigated in the experiment under the followingconditions:PNP-β-Xylopyranoside (PNPX)were used as the substrate with 1 mg/ml of substrate concentration and 5for pH value of the extracts.Enzymatic characteristics of endogenousβ-xylosidase in 4 types of wheat bran were compared.Results showed that:enzyme activities varied from different varieties of wheat bran;Differences were also found in the enzymeactivity for both coarse and fine wheat bran in the same kind;the enzyme activity in fine bran was observed higher than those incoarse bran.The maximum enzyme activity ofβ-xylosidase was found both in the coarse bran of wheat variety-zhengmai 8998and the fine bran of wheat variety-huapei 8;60℃,50℃,50℃and 60℃was the optimum reaction temperature of theendogenousβ-xylosidase for wheat varieties zhengmai 8998,huapei 8,zhengmai 366 and 9023 respectively;pH 5 was also oneof the optimal reaction conditions for the 4 varieties;For coarse bran in wheat huapei 8 and zhengmai 366,a better enzymeactivity of endogenousβ-xylosidase was got within 20~50℃,while 20~60℃was for coarse bran of wheat zhengmai 8998 and9023;Impact of temperature was not significant in the enzyme activity of endogenousβ-xylosidase;Moreover,a better enzymestability was achieved for all the 4 wheat varieties when the pH value was in the range of 5~6.Ca2+,Co2+were proved to promotethe enzyme activity,while Ag+led an inhibiting role in this regard.

BACKGROUND Berries are known to be rich in anthocyanins. These compounds give berries their distinctive colors and, more importantly, have several health benefits, such as contributing to the prevention of heart disease, cancer and inflammatory disease. In this study, anthocyanin-rich extracts from 12 colored berries found in northern China were analyzed by high-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (HPLC-DAD/ESI-MS). Total polyphenol content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC) and antioxidant capacity (AOC) of the berries were assayed. The contribution of anthocyanins in the berries to their antioxidant capacity and bioactivity was also investigated. RESULTS The 12 berries analyzed had typical profiles with different anthocyanin compositions, which can be considered as an indicator for differentiating berries. Cyanidin-3-xylosyl-galactoside and cyanidin-3-xylosyl-rutinoside were identified for the first time in Acanthopanax S. and Chinese dwarf cherry respectively. All berry extracts showed potent antioxidant activity, and TPC correlated well with AOC. Blue honeysuckle, blackcurrant and blueberry had higher TAC/TPC ratio, with anthocyanins contributing more to AOC. The higher flavonoid content in yellow raspberry and sea buckthorn might increase their antioxidant activity. In addition, wild raspberry had higher antioxidant activity than cultivated raspberries, but they all had lower anthocyanin content with less contribution to AOC. CONCLUSION There is great potential to improve human health through consumption of these colored berries, especially those high in AOC.

Wheat system flour has certain difference qualities indicators in different parts. This paper studied the distribution of arabinoxylan(abbreviated AX)andβ-xylosidase in system flour,and the correlation with flour physicochemical,texture index. AX content andβ-xylosidase activity distribution in wheat endosperm is gradually increased from the inside to the outside,1B<2B<3B,1M<2M<3M. On theρ<0.01 level,AX and ash significantly correlated,AX and water,extension resistance was positively correlated;β-xylosidase and AX,ash showed correlation.

Resibufogenin (RB), a major bioactive bufadienolide, has the potential anticancer activity. In the present work, biotransformation of RB by Actinomucor elegans AS 3.2778 yielded five products, namely 3-oxo-resibufogenin (1), 3-epi-resibufogenin (2), 3-epi-12-oxo-hydroxylresibufogenin (3), 3α-acetoxy-15α-hydroxylbufalin (4), and 3-epi-12α-hydroxylresibufogenin (5), respectively. Among them, metabolites 3 and 4 are previously unreported. The chemical structures of metabolites 1-5 were fully elucidated on the basis of 2D NMR and HR-MS. The highly stereo- and regio-specific isomerization, hydroxylation, and esterification reactions were observed in the biotransformation process of RB by A. elegans. Their cytotoxicities against A549 and H1299 cells were evaluated.

以PNP-β-xylopyranoside为底物确定小麦麸皮内源性β-木糖苷酶的酶活力测定条件,并对β-木糖苷酶的酶学性质进行研究.试验确定酶活测定条件为底物浓度1 mg/mL,提取液pH 5.木糖苷酶的酶学性质:最适反应温度为60℃,在20～50℃时稳定性好,保温60 min后其活力可保持在70％以上,最适pH值为5,在pH值5～6时对木糖苷酶的破坏力相对较小,保温60 min后其活力仍可保持在80％以上.动力学参数Km和Vmax分别为4.518 mg/mL,0.392 μmol/(min·g).通过对4种小麦麸皮酶活力进行测定发现:细麸中的β-木糖苷酶活性均高于粗麸,粗麸中郑麦8998的木糖苷酶酶活最大,细麸中花培8号小麦木糖苷酶活性最大.

Ursolic acid in Cynomorium songaricum was ultrasonically extracted and detected by HPLC. According to singlefactor experiments,three levels of four factors including ethanol concentration,material -liquid ratio,ultrasonic time, and ultrasonic power were selected for the orthogonal design.The results showed that the calibration curve of ursolic acid was linear (r=0.999 8) in the range of 4.0~16.0 μg/μL.The equation was y=622.7x-85.517,r=0.999 8,and recovery was 98.08%. The optimum extraction was carried out in 85%(V / V) ethanol for 30 min with the ultrasonic power of 150 W,and the material-liquid ratio 1:25.Under the optimal conditions,the content of ursolic acid was 1.53%.The method can extract ursolic acid efficiently,and provide a reference for evaluation ursolic acid in medicinal materials.

In order to increase the yield of endogenousβ-xylosidase from wheat bran,this article optimized the extraction conditions ofβ-xylosidase by use of response surface methodology. Based on the single factor experiments,it designed the response surface experiments according to Box-Benhnken Design method by taking extraction pH,material-to-water ratio,extraction time as independent variables and the yield of endogenousβ-xylosidase as response value,carried out significance and interaction analysis to determine the optimum extraction conditions,and verified the results. The results showed that the yield of endogenousβ-xylosidase could reach 84.19 mU/g under the optimum extraction conditions of extraction pH 4.93,material-to-water ratio 1∶9.85 g/mL,extraction time 36.85 min,and the result was very close to the predicted value optimized by response surface fitting.

In this paper, the microbial transformation of resibufogenin (1) by Curvularia lunata AS 3.4381 was investigated, and four transformed products were isolated and characterized as 3-epi-resibufogenin (2), 12α-hydroxy-3-epi-resibufogenin (3), 12-oxo-16β-hydroxy-3-epi-resibufogenin (4), and 12β,15-epoxy-3-epi-bufalin-14,15-ene (5). Among them, 4 and 5 are new compounds, and isomerization, hydroxylation, and oxidation reactions in microbial transformation process were observed. Additionally, the cytotoxicities of transformed products (2–5) were also investigated.

在储藏过程中,为了提高馒头质量,降低老化速度,采用TA-XT Plus物性仪测定馒头样品硬度及NMR技术测定其水分分布变化,研究木聚糖酶对馒头样品老化速度的影响。结果表明:馒头储藏0~36h内,馒头的表皮硬度及芯部硬度均缓慢增加,相对于空白馒头样品,添加XYL馒头样品硬度较弱;达到36h时,硬度显著增加,特别是添加L-XYL的馒头样品。馒头储藏期间,质子信号A及A1持续下降。在0~36h内,所有添加木聚糖酶的馒头样品质子信号下降速度较慢;36~120h内,添加S-XYL的馒头样品质子信号下降缓慢,但添加L-XYL的馒头样品质子信号下降速度快。由此可知,相对于空白样品,在0~36h内,添加XYL的所有馒头样品老化速度较慢,保鲜度较好。在36~120h内,添加S-XYL的老化速度较慢,而添加L-XYL的老化速度较快。

In order to increase the dough mechanical processing performance and the quality of products, and select the appropriate xylanase added to the wheat flour, the effects on dough rheology properties were studied using the Kieffer test of TA-XT Plus to determine the resistance to stretching (R max ) and the dough extensibility (Ex) by adding one kind of xylanase to four kinds of wheat flour and three kinds of xylanase to one kind of wheat flour in this experiment, respectively. The results showed that the R max of dough decreased while the Ex increased with the dosage of xylanase increasing. Relative to the strong dough, soft dough R max decreased faster. The dough rheology properties were affected by ND-XYL and NOV-XYL significantly. So, xylanase softened and slacked the dough, especially the wheat flour with lower gluten. The ND-XYL and NOV-XYL were more suitable for the processing of the dough.

To analyze the epitope of Blakeslea trispora CarRA protein and prepare its polyclonal antibody. Combined with existing antigen epitope selection principle, the Blakeslea trispora CarRA full-length sequence was analyzed by using the bio-informatics software GOLDENKEY to detect the structure of amino acids and select its epitopes. The Blakeslea trispora CarRA peptides fragment was synthesized by solid-phase peptide synthesis method and purified by HPLC. The synthetic antigen was conjugated with the keyhole limpet hemoyanin (KLH), and then rabbits were immunized with this antigen and the antibody was examined. The results show that the antibody titer is as high as 1:32000. Through Dot blot analysis, it was proved that this peptide antibodies could react with Blakeslea trispora CarRA. All these prove that the antibody has wonderful reaction and speciality. A CarRA-specific antibody was succeddfully developed, which lays foundation for further studies of fermentation accelerator mechanisms, effects on Blakeslea trispora metabolic networks, CarRA quantitative research and the function of CarRA.