2015年吉林省地方特色食品辣白菜中常用添加剂和硝酸盐含量监测结果分析

目的：分析了解2015年吉林省特色食品朝鲜族辣白菜的质量状况,为今后开展风险评估、制定地方标准、跟踪评价企业标准提供数据资料。方法：分别在延边州地区、吉林市地区、长春市地区、通化市地区和白城市地区等超市、农贸市场采集100份辣白菜样品,采用分光光度法和液相色谱法测定硝酸盐、亚硝酸盐、苯甲酸、山梨酸和糖精钠的含量,并根据《食品安全国家标准 食品添加剂食用标准》(GB 2760-2014),对检测结果进行分析评价。结果：吉林省地方特色食品朝鲜族辣白菜中苯甲酸、山梨酸、糖精钠和亚硝酸盐都有不同程度的检出,检出率分别为34%、19% 、5%和82%,其中各有1份样品苯甲酸、山梨酸含量超标,有2份样品中亚硝酸盐含量超标;所有样品中均检出硝酸盐,检出含量范围为114mg/kg—3010mg/kg。结论：定型包装的辣白菜要重点监测食品添加剂的使用情况,同时由于硝酸盐和亚硝酸盐的含量和检测率都比较高,建议应避开腌渍初期食用辣白菜。     

Enhancement of bio-electrocatalytic oxygen reduction at the composite film of cobalt porphyrin immobilized within the carbon nanotube-supported peroxidase enzyme

Combination of multi-walled carbon nanotubes, cobalt porphyrin, and peroxidase (horseradish, cabbage) enzyme in the film (deposited onto glassy carbon electrode substrate) produces a bio-electrocatalytic system capable of effective reduction of oxygen in such neutral media as 0.1 mol dm⁻³ KCl and 0.1 mol dm⁻³ KCl + 0.01 citrate buffer (pH 6).Carbon nanotubes have been modified with ultra-thin layers of 4-(pyrrole-1-yl) benzoic acid, or phosphododecamolybdate, to form stable colloidal suspensions of carbon nanostructures. The resulting inks have been utilized during sequential deposition of components. Co-existence of cobalt porphyrin, peroxidase enzyme together with dispersed carbon nanotubes leads to synergistic effect that is evident from some positive shift of the oxygen reduction voltammetric potentials (more than 50 mV in citrate buffer) and significant (ca. twice) increase of voltammetric currents (relative to those of the enzyme-free system). The multi-component bio-electrocatalytic film has also exhibited relatively higher activity towards reduction of hydrogen peroxide. It is reasonable to expect that the reduction of oxygen is initiated at cobalt porphyrin redox centers, and the undesirable hydrogen peroxide intermediate is further reduced at the horseradish or cabbage peroxidase enzymatic sites. An important function of carbon nanotubes is to improve transport of electrons within the bio-electrocatalytic multi-component film.     

大白菜“3414”施肥试验初报

通过大白菜测土配方施肥"3414"试验,结果表明,以氮肥增产效果最佳,钾肥次之,氮磷钾施肥效应为N>K>P。通过三元二次肥料效应模型回归方程算出大白菜667 m2最高产量3 532.82 kg,667 m2N、P2O5、K2O最佳施用量分别为21、3、12 kg,m(N)∶m(P2O5)∶m(K2O)=1∶0.14∶0.57。     

太阳能脱水车间湿差脱水技术研究

采用太阳能资源与西北干燥空气合理结合的方式,以娃娃菜为例进行脱水干燥实验研究。研究西北地区不同季节的气候条件,对娃娃菜实际脱水速度与理论空气脱水速度的影响。得出全年干燥参数。研究表明,干燥室满载脱水时,室外干空气绝对湿度显著低于室内,不论白天和夜间都可以有效辅助太阳能进行脱水,150kg娃娃菜全年干燥时间为28～72h,干燥效率保持在80%左右。夏季将最大节能79%,秋季最小节能47%。利用spss17.0软件对实验结果进行分析表明,Cubic模型拟合效果较理想。     

Se improves indole glucosinolate hydrolysis products content, Se-methylselenocysteine content, antioxidant capacity and potential anti-inflammatory properties of sauerkraut

Selenium (Se) has a well-known role in prevention of chronic diseases associated with oxidative stress and inflammation. The objective was to produce Se-enriched sauerkraut and to study the effect of selenite addition on indole glucosinolate hydrolysis products, vitamin C, Se biotransformation and microbial quality. The antioxidant activity of sauerkraut and its ability to inhibit NO production in LPS-induced macrophages were also examined. White cabbage was naturally fermented with 0.3 mg of Na₂SeO₃/kg fresh cabbage (NFSe) or without Se addition (NF). Total Se content reached up to 1.29 μg/g d.m. (0.11 μg/g f.m.). Selenomethylselenocysteine was the major Se form found in NFSe cabbage. Se addition caused a slight reduction of ascorbigen (6%) and vitamin C (5%) contents in sauerkraut (P ? 0.05); however, lactic acid bacteria increased (3%), and the formations of indole-3-carbinol and indole-3-acetonitrile were markedly enhanced (74% and 13%, respectively). NFSe cabbage extracts showed higher (P ? 0.05) antioxidant activity (163 μmol trolox/g d.m.) and inhibition of NO production in LPS-induced macrophages (IC₅₀ = 44.0 μg/ml) than did NF cabbage extracts. Consequently, Se-enriched sauerkraut can be considered as a health-promoting food.     

脱水甘蓝护色工艺的优化

甘蓝在干燥过程中叶绿素含量降低,产品感官品质下降。采用正交试验方法优化脱水甘蓝护色工艺,以期提高脱水甘蓝的感官品质。正交试验以叶绿素残留率为指标,优化最佳护色工艺。结果显示,采用浓度为1%的Na2CO3溶液浸泡15min,100℃热烫1.5min,脱水甘蓝叶绿素保存率为52.3%,此时过氧化物酶相对酶活小于5%,可以有效保持甘蓝的原有颜色。     

紫甘蓝花色苷的分离纯化

初步研究了紫甘蓝花色苷在SephadexLH-20凝胶层析柱上最佳的分离条件,以及在最佳条件下收集合并各组分,并进行紫外可见全扫描、薄层色谱实验。结果表明:当以30%乙醇为洗脱液,流速为1mL/min时,紫甘蓝花色苷的分离效果最好,共收集合并4个组分。紫外可见全扫描确定Ⅰ组分为非花色苷,Ⅱ、Ⅲ、Ⅳ组分为花色苷,薄层色谱实验表明Ⅱ、Ⅲ组分分别分离出2组花色苷,Ⅳ组分分离出3组花色苷。     

制造执行系统在烟草企业中的应用

随着社会信息化的快速变革,烟草行业的信息化建设也在不断深入和发展,＂以信息化促进工业化＂成为烟草工业企业提高生产能力,更大满足市场需求的必要手段。结合杭州卷烟厂MES项目,分析了生产执行系统在烟草工业企业中的设计模型,设计原则,功能模块以及平台技术,呈现了生产执行系统在杭州卷烟厂生产过程中的串联和纽带功能。     

宁夏菜心不同部位发酵理化品质及挥发性风味物质的分析

为探究宁夏菜心湿态发酵的可行性,该研究通过对宁夏菜心基部茎、顶端茎、叶子以及菜心整体进行乳酸菌接种发酵,解析发酵前后微生物、有机酸、亚硝酸盐、抗氧化能力、生物胺以及挥发性风味物质的变化规律。研究表明,发酵后菜心各部位总有机酸含量升高、亚硝酸盐含量降低、抗氧化能力降低和生物胺含量降低,基部茎、叶子、整颗菜心的挥发性性风味物质种类含量均升高;菜心叶子经发酵后亚硝酸盐含量和生物胺含量分别降解了0.30和22.78 mg/kg,DPPH自由基清除率62.06%,总有机酸含量3 212.70 mg/100 g,挥发性风味物质种类丰富,检出48种化合物,相对含量为123.68 g/g。与其他发酵组相比,叶子发酵组的理化指标和挥发性风味物质含量均处于较优水平。以上研究表明宁夏菜心可作为泡菜发酵的原材料,且较优发酵部位是叶子,该研究为菜心的湿态发酵奠定基础。     

正交试验法优化卷心菜叶中绿原酸提取工艺研究

以卷心菜叶为原料,研究采用微波法辅助提取卷心菜叶中绿原酸的提取工艺。实验中以绿原酸的提取率为指标,以乙醇为提取剂,考察乙醇体积分数、料液比、微波温度、微波时间、微波强度等因素对卷心菜叶中绿原酸提取率的影响。通过L16(45)正交优化绿原酸提取工艺,结果显示,最佳工艺条件为:微波温度60℃、微波时间6 min、微波功率300 W、乙醇体积分数60%、料液比1∶20。在此最佳工艺条件下,卷心菜叶中绿原酸的提取率为1.2682%。