腐胺对盐胁迫下小麦幼苗根中活性氧代谢的影响

以小麦（T.aestivm L.）＂陇春23号＂为实验材料,测定了外源腐胺（Put）对NaCl胁迫条件下,小麦根细胞的膜透性、丙二醛（MDA）含量、活性氧（ROS）的含量、抗氧化酶活性,结果表明外源Put处理使NaCl胁迫下小麦根中细胞膜透性降低,MDA含量减少,抗氧化酶（CAT,SOD,APX,POD）的活性升高,O2.-的产生减少,但H2O2的含量升高。进一步测定二胺氧化酶（DAO）和多胺氧化酶（PAO）的活性,结果 DAO和PAO的活性升高,表明外源腐胺能通过提高抗氧化酶的活性减轻NaCl对小麦根的氧化伤害,但H2O2在此实验中不是对小麦根起伤害作用,可能作为信号分子起作用。     

Concentrations of biogenic amines in fish,squid and octopus and their changes during storage

The concentrations of seven biogenic amines (BA) were simultaneously determined in 74 samples of fish, squid and octopus, by the method of HPLC coupled with pre-column derivatisation. The relationship between the formation of BA in aquatic products and the growth of microbial flora during storage was also investigated. Results showed that putrescine, cadaverine, histamine and tyramine were the dominant BA in the studied samples, but the concentrations of histamine and tyramine were mostly less than 50 and 100 mg kg⁻¹, respectively. Freezing can effectively prevent the formation of BA, but the levels of putrescine, cadaverine, histamine and tyramine significantly increased (p < 0.05) during storage at 4 and 25 °C. The growth of mesophilic or psychrophilic bacteria in blue scad and octopus strongly and positively correlated with the formation of amines (such as putrescine, cadaverine, histamine and tyramine) during storage, except for histamine in octopus.     

Amperometric Biosensor for Total Histamine, Putrescine and Cadaverine using Diamine Oxidase

Diamine oxidase was purified from porcine kidney to homogeneity and immobilized onto a porous preactivated nylon membrane. The enzymic membrane was attached to an amperometric electrode for determination of the total concentrations of histamine, cadaverine and putrescine accumulated in fish fillets during storage. For detecting hydrogen peroxide released, the working platinum electrode was poised at +400 mV vs Ag/AgCl to prevent electrode fouling as well as minimize electroactive interferences. The biosensor was linear up to 6 mM with a lower detection limit of 25 μM for the three substrates and steady state response was achieved within 1.5 min. The enzyme membranes were stable at 5°C for 2 mo and usable for at least 60 assays.     

Monitoring of beef aging using a two-line flow injection analysis biosensor consisting of putrescine and xanthine electrodes

A two-line flow injection analysis (FIA) biosensor was developed which can simultaneously detect bacterial spoilage and the progress of aging. This FIA biosensor was composed of a putrescine oxidase immobilized electrode and a xanthine oxidase immobilized electrode as detectors. The putrescine electrode measures putrescine and cadaverine which are produced by bacteria, and the xanthine electrode measures hypoxanthine and xanthine which accumulate in meat with aging.

The analytical conditions for this system were set as follows; flow rate, 1 ml/ min; water bath temperature, 30 °C; flow buffer, 0.1 M phosphate buffer (pH 7.0); injection volume for putrescine electrode, 200 μl; injection volume for xanthine electrode, 40 μl; and measurement cycle, 2 min.

The linear relationship for standard solution was between 20 and 800 nmol/ml in the putrescine electrode and between 0.1 and 3.0 μmol/ml in the xanthine electrode. The coefficients of variation in standard solutions were 2.14% with the putrescine electrode and 2.83% with the xanthine electrode. The coefficients of variation values in the specimen solution were 3.22% and 3.76%, respectively.

This two-line FIA biosensor was applied to the vacuum-packed beef stored at 0, 5 and 10 °C. The progress of aging could be monitored at all temperatures, and the bacterial spoilage could be detected before the appearance of putrid odor at 5 and 10 °C. However, at 0 °C the putrid odor did not appear during storage, and neither putrescine nor cadaverine was detected. Thus, this FIA biosensor was confirmed to be useful for the quality control of beef aging at 5 and 10 °C, but not at 0 °C.     

Quantitative changes in bacteria, amino acids and biogenic amines in sardine (Sardina pilchardus) stored at ambient temperature (25–28°C) and in ice

Freshly caught sardines contained high levels of bacteria located mainly on the skin and the gills. These bacteria invaded and grew rapidly in sardine muscle, reaching 5x10⁸ c.f.u. g^-1 and 6x10⁸ c.f.u. g^-1 respectively after 24h at ambient temperature and 8 days in ice.
Histidine, arginine, lysine, tyrosine and methionine levels decreased during storage. The other amino acids, except proline and taurine, accumulated in the fish muscle, indicating an extensive proteolysis.
Histamine, cadaverine and putrescine accumulated to levels of 2350ppm, 1050ppm and 300ppm respectively, after 24h storage at ambient temperature. Histamine and cadaverine reached similar levels after 8 days storage in ice, whereas putrescine formation was insignificant. Spermidine and spermine levels increased slightly under ambient conditions.
Salting the fish at 8% delayed bacterial and chemical changes but only in iced sardines.
The high content of free histidine found in sardines and the susceptibility of its muscle to histamine and cadaverine formation could explain its increasing implication in incidents of histamine poisoning.     

腐乳中生物胺的存在、污染途径及控制研究进展

腐乳是我国大众喜爱的一种传统发酵豆制品,由于其发酵过程中形成的生物胺具有潜在的毒性而成为目前研究的热点问题之一。文章综述了腐乳的科研工作者对生物胺存在情况的研究现状,对腐乳中生物胺的检测方法现状及控制标准进行了分析,对腐乳中生物胺的来源及控制手段提出了建议,为腐乳安全性评价及未来标准修改完善提供参考。     

大蒜精油对熏马肠中德氏乳杆菌产腐胺的影响机制

研究不同质量浓度大蒜精油对熏马肠中德氏乳杆菌产腐胺的影响机制。利用反转录实时荧光定量聚合酶链式反应技术分析供试菌在不同大蒜精油质量浓度下的胍基丁胺脱亚胺酶相关基因表达情况,使用超高效液相色谱连续48 h监测纯菌体系中的腐胺产量;并将德氏乳杆菌接入到含不同质量浓度大蒜精油的熏马肠中发酵28 d,期间取样测其菌落总数、pH值及腐胺积累量。结果表明：无论是在纯菌培养还是在熏马肠发酵过程中,大蒜精油都能明显抑制细菌的增长,在纯菌体系中会明显抑制pH值的下降,但对熏马肠的最终pH值影响不明显;大蒜精油对调节基因aguR的转录影响不明显,但能极显著抑制操纵子aguBDAC的转录（P＜0.01）;增加纯菌体系以及熏马肠发酵过程中的大蒜精油质量浓度均能明显减少腐胺的生成。     

Formation of selected biogenic amines in carp meat

Changes in biogenic amine content in carp (Cyprinus carpio) muscle were studied. Fish halves and minced fish meat were stored at 3 and 15 °C. Both the temperature of storage and the type of meat processing had statistically important effects on the amine content. In another set of experiments, temperature and the preservative effects of Purac at various concentrations were tested. Purac can extend the shelf‐life of fish halves stored at 3 °C by about 5 days. Putrescine concentration is proposed as a chemical indicator of carp meat quality. Decomposition is apparent when the putrescine content in the meat exceeds 20 mg kg^?1. © 2002 Society of Chemical Industry     

Changes in biogenic amines of silver carp (Hypophthalmichthys molitrix) fillets stored at different temperatures and their relation to total volatile base nitrogen,microbiological and sensory score

BACKGROUND: Biogenic amines have received considerable attention owing to their undesirable effects in humans. There are few studies of changes in biogenic amine contents related to freshwater fish. Silver carp is an important freshwater fish species in China. This study aimed to investigate the changes in biogenic amines and their relation to total volatile base nitrogen (TVB‐N), microbiological and sensory score of silver carp fillets stored at 0, 3 and 15 °C. RESULTS: The total biogenic amine contents of all silver carp fillets (regardless of storage time and temperature) ranged from 13.05 to 318.10 mg kg^?1. Putrescine and histamine were the main biogenic amines in silver carp fillets during storage. Cadaverine was only detected after 12 days at 3 °C and after 2 days at 15 °C. Spermidine and spermine contents increased during the early storage period and then slightly decreased. CONCLUSION: Low temperature could control the quality of silver carp fillets by inhibiting the contents of biogenic amines. Putrescine showed significant correlation with TVB‐N, total aerobic content, sensory score, tryptamine and phenylethylamine. Putrescine was a good quality marker of silver carp fillets in the cold chain. Copyright © 2012 Society of Chemical Industry