流通领域中环境因素对盐渍榨菜品质变化的影响

研究盐渍榨菜在流通过程中环境因素:流通温度、流通湿度、光照强度、流通时间作用下的品质变化规律,采用响应面法得出各因素对盐渍榨菜品质影响,并确定相应的数学模型,从而得出影响因素与榨菜品质变化的关系.     

Inhibition of Listeria monocytogenes and Salmonella by Combinations of Oriental Mustard,Malic Acid,and EDTA

The antimicrobial activities of oriental mustard extract alone or combined with malic acid and EDTA were investigated against Salmonella spp. or Listeria monocytogenes at different temperatures. Five strain Salmonella or L. monocytogenes cocktails were separately inoculated in Brain Heart Infusion broth containing 0.5% (w/v) aqueous oriental mustard extract and incubated at 4 °C to 21 °C for 21 d. For inhibitor combination tests, Salmonella Typhimurium 02:8423 and L. monocytogenes 2–243 were individually inoculated in Mueller Hinton broth containing the mustard extract with either or both 0.2% (w/v) malic acid and 0.2% (w/v) EDTA and incubated at 10 °C or 21 °C for 10 to 14 d. Mustard extract inhibited growth of the L. monocytogenes cocktail at 4 °C up to 21 d (2.3 log₁₀ CFU/mL inhibition) or at 10 °C for 7 d (2.4 log₁₀ CFU/mL inhibition). Salmonella spp. viability was slightly, but significantly reduced by mustard extract at 4 °C by 21 d. Although hydrolysis of sinigrin in mustard extract by both pathogens was 2 to 6 times higher at 21 °C than at 4 °C to 10 °C, mustard was not inhibitory at 21 °C, perhaps because of the instability of its hydrolysis product (allyl isothiocyanate). At 21 °C, additive inhibitory effects of mustard extract with EDTA or malic acid led to undetectable levels of S. Typhimurium and L. monocytogenes by 7 d and 10 d, respectively. At 10 °C, S. Typhimurium was similarly susceptible, but combinations of antimicrobials were not more inhibitory to L. monocytogenes than the individual agents.     

我国煤矿安全事故统计分析及预测

为分析我国煤矿死亡事故发生的规律和准确判断未来我国煤矿的整体安全生产形势,根据2009—2018年我国煤矿死亡事故统计数据,从煤矿事故发生级别、事故类型2个维度对我国的煤矿生产安全事故进行了研究。通过SPSS 25.0软件建立Brown线性趋势模型,并对我国2009—2018年煤矿百万吨死亡率进行验证,最后预测2019—2021年我国煤矿百万吨死亡率。结果表明2009—2018年煤矿事故起数和死亡人数处于持续下降趋势,我国煤矿安全形势持续稳定向好;在事故发生级别上,一般事故发生的事故起数最多,累计造成的人员死亡也是最高,其次是较大事故和重大事故,特别重大事故发生起数在2016年出现了回升,造成了大量人员伤亡,但是2017年出现回落,没有发生特大事故;在事故类型中,顶板事故发生频率最高,瓦斯事故是一次伤害造成死亡人数最多的;Brown线性趋势模型对2009—2018年煤矿百万吨死亡率验证表明,相对误差基本上都在30%以内,R^2=0.931,接近于1,均方根误差(RMSE)和正态化的BIC均较小,表明Brown线性趋势模型模型的拟合效果比较好,预测精度较高。对我国煤矿事故发生规律的研究和煤矿百万吨死亡率的预测验证分析,使煤矿企业制定完备的安全管理措施和避免煤矿事故的发生具有重要意义。     

赤砂糖中二氧化硫含量测定的不确定度分析

采用GB 5009.34-2016《食品安全国家标准食品中二氧化硫的测定》中蒸馏法对赤砂糖中二氧化硫进行测定,分析该方法不确定度来源,对不确定度各个分量进行评估.结果表明,测定赤砂糖中二氧化硫含量不确定度的主要来源为标准滴定溶液消耗的体积和重复性测量,当二氧化硫含量为0.053 g/kg时,扩展不确定度为0.0034 ...     

Relative expression and regulation by short-term fasting of lysophosphatidic acid receptors and autotaxin in white and brown adipose tissue depots

Lysophosphatidic acid (lysoPtdOH) levels have previously been reported to decrease in rodents with short-term fasting. We investigated whether a 16 h fast would change expression of autotaxin, the predominant phospholipase D responsible for adipose-derived lysoPtdOH synthesis, or any of the lysophosphatidic acid receptors (1–6) in four white adipose tissue (WAT) depots and interscapular brown adipose tissue (BAT) in male C57Bl/6J mice fed ad libitum, or fasted for 16 h. Aside from small inductions of Lpar1 in epididymal WAT and Lpar2 in epididymal and inguinal WAT, no significant changes were observed in expression of the Lpar family members, or autotaxin in perirenal, retroperitoneal, epididymal, or inguinal WAT or BAT with fasting. Comparison of the relative expression of Lpar1-6 in various depots showed that Lpar6 was the predominant Lpar in both WAT and BAT, and suggests that further work on the adipose-specific role of Lpar6 is warranted.     

非病原细菌对烟草赤星病菌的生物抑制作用研究

从烟草根际土壤和烟草、黄瓜、番茄、桑树的茎、叶部位分离了５０株非病原芽孢杆菌和假单孢杆菌,在培养条件下对烟草赤星病菌进行了生物拮抗性测定。结果表明,非病原细菌对烟草赤星病菌有效强的拮抗作用。在不同来源的非病原细菌中,以来自烟草根际的非病原细菌对烟草赤星病菌的拮抗作用最强。在拮抗菌对目标菌烟草赤星病菌生长发育影响中发展,受拮抗菌作用,目标菌菌丝形态产生变异,生长发育受到影响。选取拮抗性较强的拮抗菌,在温室条件下处理（喷洒）烟苗,结果对烟草赤星病具有明显的抑制作用。     

云南新平腌菜发酵过程中品质变化规律

目的:获得云南传统新平腌菜最佳发酵时间。方法:对不同发酵时间下新平腌菜进行感官评价和质构测定,并按国标法测定pH值和亚硝酸盐含量。结果:随着发酵进行,感官方面,新平腌菜色泽和质地得分逐渐上升,6 d后趋于平稳,香气和滋味得分先升高,7 d后开始下降;质构方面,菜柄的咀嚼性从发酵第7天开始趋于稳定;发酵7 d时pH值为4.67,之后下降并稳定在4.3左右;发酵20 h时出现亚硝峰,2 d后亚硝酸盐含量下降到1~3 mg/kg。结论:综合考虑感官、质构、pH值及亚硝酸盐含量变化,发酵7 d左右的新平腌菜品质最佳。     

雪里蕻腌菜特征风味物质的分离和鉴定

运用色-质(GC/MS)联用技术对雪里蕻腌菜的风味物质进行了研究,以期发现能显著影响其风味特性的关键性成分.首先,对雪里蕻腌菜卤汁的乙醚萃取浓缩液组分进行了鉴定,结果发现有机酸组分8个,醇类组分4个,腈类组分2个,酯类组分1个,芳香烃2个.经动态顶空吸附雪里蕻腌菜挥发性组分并进行组分离,在GC-MS图谱上进行组分的分离鉴定,其特征风味在碱性组分中嗅感强烈.雪里蕻腌菜挥发性成分经GC-MS检测解析为烃类、醇类、酯类、腈及杂环化合物,其中丁烯腈及苯并噻唑与雪里蕻腌菜特征风味形成密切相关.     

茎瘤芥瘤茎质构分析

质构是榨菜重要的品质特征,与榨菜原料（茎瘤芥瘤茎）的质构和加工工艺密切相关。 采用质构分析（TPA）仪对茎瘤芥瘤茎及 榨菜进行质构分析,结果表明,茎瘤芥瘤茎头部与中部的弹性、咀嚼性和粘结性,头部与尾部的硬度和脆度无显著性差异（P＞0.05）, 其他质构指标均有不同程度的显著性差异（P＜0.05）;各个部位质构指标分析数据离散程度小;茎瘤芥瘤茎各个部位的咀嚼性-粘结 性、咀嚼性-弹性相关性较高;茎瘤芥瘤茎质构各个指标的相关性的规律性与取样方式有关,芯部硬度与脆度的相关性较高,而皮层 硬度与脆度的相关性较低。 榨菜的脆度值较茎瘤芥瘤茎减小,而榨菜的硬度值、弹性值、内聚性值、咀嚼性值和粘结性值较茎瘤芥瘤 茎增大。